For anyone coming straight to the comments looking for an answer to the question: it turns into CO2 (and a bit of water) and you breathe it out.
When you realize that you have to breathe out all the weight you lose, I think it gives you a bigger appreciation for how difficult weight loss can be.
I've lost 16kg this year, which I attribute to 3 things:
1. being fairly strict with calorie intake - though I have gone over my limit a whole bunch of times
2. upping my running game - 80km+ most months
3. being diagnosed asthmatic (after 40 years of merely "you've got shitty lungs, sorry") and prescribed a morning+night inhaler
Dieting isn't new to me, I've been a fat bastard all my adult life. Previous attempts at losing weight have involved doing (1)+(2) and each time I lost weight and got faster. But with the diagnosis at the start of this year, and despite a higher calorie allowance, I've smashed my PBs at various distances - multiple times - and lost more weight (NB. because I started higher; I'm not at a record low, yet). So it seems pretty intuitive to me that "I'm better at breathing" has played a hell of a part.
I highly recommend a meal tracker app for anyone who's looking to lose. I avoided it for ages. I didn't want to be "one of those people". I felt like I ate fairly well and was working hard enough, I shouldn't have to stoop to that level.
I started bike commuting over 3 months ago now, but my weight was only increasing, and I was pretty sure my diet was the same as ever -- healthy breakfast, fairly healthy lunch, healthy dinner -- mostly homemade, rarely eat out, etc. My only real "sin" was drinking, but it didn't seem to matter if I drank every night or cut back to weekends only (which I had when I started biking, working out more, and again seeing no real benefit).
So I finally broke down and started using one a few weeks ago and it's made all the difference in the world. The biggest advantage is the immediate metrics. I HATED the idea that I could work my ass off for a week or three and see my weight go up, or down, and really have no idea what was happening on a day to day basis. By tracking my meals (plus workouts and commuting between Strava and Apple Health sync), I can immediately see if I'm ahead or behind. It's the feedback I had been craving for years. Where I thought the point of one of these apps was to try to learn what's healthy to eat and to be calorically restrictive (which was unappealing.. again, I don't want to be "that guy"), it's really the realtime data that's useful.
In my particular case, I've learned I actually eat amazingly well for the most part, and it's very easy to run huge caloric deficits during the week. Without even trying I was seeing a deficit of perhaps 1500kcal/day (during the week). What was killing me was beer (on weekends, but then again, 3/7 days is almost half the days of the week) and the occasional big consumption day. You know, have a big breakfast on the weekend, a big lunch, some drinks, and pretty soon 1 day could almost kill a whole week's progress. The tracking has given me the ability to say actually, yeah, one more beer really WILL push me over the edge from a deficit to a gain. I don't really need that 3rd bagel. And so on. And given that I tend to consume more on weekends, and typically I only got a single short run in one weekend day, those weekends were just killing my progress.
On the other hand, it's made me mind snacking a bit less -- the deficits I run during the week are so big that a couple fun size bag of Skittles (we just ran out of halloween candy at work) make almost no difference in my daily progress.
I'm just starting out with it, but again, the realtime feedback has made me realize how much EASIER it's going to be than I ever expected. When I felt I had nothing left to easily cut or change, I actually found the solutions were far easier than I realized, and it's helped me to quantify things that I knew were bad but didn't really appreciate the magnitude of.
And because I no longer have to just "do my best" or a month and hope it shows up on the scale, there's no more disappointment/discouragement.
For me, the slight added friction of tracking what I eat makes it a lot easier to avoid random snacking and excessive eating. It's silly, but "I'll have to put this in the app" is often a bigger disincentive than "I'll get fatter" in the moment.
Couldn't agree more. Also didn't want to be that person tracking calories ... but now that I do and can look back, my perspective is more of "let's face it, losing weight is not easy" and those people tracking were doing hard work.
But you realize, finding your macro deficit combined with an app like my fitness pal makes it SIGNIFICANTLY easier. Losing weight becomes simple arithmetic.
Alcohol is rough. So many people have no idea what a drink actually contains calorie wise. Even the new and popular alcoholic seltzers will list something like "100 calories", and then the nutrition facts will list something like "5 carbs". With 4 calories per carb ... 4 * 5 does not equal 100. It is more accurate to just take the calorie count of 100 and divide by 4. Now you have a 25g of carbs drink, which is fine, but you need to factor that into your daily tracking.
Alcohol has calories per gram, but it isn't required to be listed. This makes craft beers very interesting. Take a 16oz can of some double IPA at 8% and boom, you have around 320 calories in that one drink ... or 80 carbs if you look at it that way.
I've tried to simplify it a bit with this calculator that actually factors calories/g of alcohol.
I need to do more reading on this calories per carb thing. I don't get it at first glance.
I also hated the "if it fits your macros" type thing. I'm not a body builder, what do I care? But when you see the real impact of what you're about to eat it actually frees you quite a bit (assuming you generally eat well). I'm actually happy to grab that extra piece of cheese because I can easily take the calorie hit, I gotta eat something, and some protein and fat seems better than carbs.
I did the math on craft beer last winter, and cut back on beer for a bit, but it never stuck. 2.5cal per ounce per % abv. It would not be unheard of to drink half a POUND of calories in an afternoon, say, watching football. As I've switched to wine, even when I have more than I should and input the numbers, I simply cannot believe my eyes in terms of how FEW calories it has. I overestimate my consumption to be "conservative" and yet it still barely makes a dent in my diet. It's amazing.
I've done dry january a few times, and never saw a bit of benefit. But a month is a short time to see a trend, and it's not a time when I'm training for a race or doing much cycling; most of us are indoors a lot, maybe you have a dessert once or twice a week when normally you'd have none, and bam, you get discouraged and it feels like cutting out alcohol entirely makes no difference at all. Again, when you can see the data on a day-to-day (or even minute by minute) basis, it's so freeing.
Looking at myfitnesspal right now, my 'goal' is 2220kcal (which I think is a 500kcal deficit since I set it to lose 1lb/week). goal 2220, -470 food, +1141 excercise and I've got 2934 left to 'spend' for the rest of the day. It's amazing to get to work and have more than your entire BMR left to eat.
I am embarking on my third attempt at major weight loss -this time medically supported.
The first two times were a success as I was doing Weight Watchers and they stress always 'tracking' - meal logging and accounting for your meals before eating - and planning your meals ahead. All of my failures came after stopping Weight Watchers for one reason or another (inconvenience of weekly meetings, wanting to save some money instead of paying for the subscription, etc).
Moving into medically supported weight loss has changed my view toward some of the pseudo-science of Weight Watchers, but one thing both approaches have in common is keeping a food diary or accounting of what you are going to eat and holding yourself accountable to that. I'm down ten pounds over the last two months and well on my way thanks to getting back into using a food diary (in my case, MyFitnessPal).
I highly recommend it to anybody who wants to lose a lot of weight over the long term, but it's also good for generally accountability. After I lose the amount of weight I'm trying to I will continue to keep a food diary.
This is great advice but just be aware that calorie calculations in Strava are often way off: too high for walking / running and too low for cycling. So you can't reliably use their numbers to see if you're ahead or behind.
Good information. I'm pretty happy with the consistency of the calorie counts on Strava (Apple Watch has HRM built in) vs Peloton bike (with chest HRM strap), so I'm assuming you're referring to Strava's estimates without HRM (not sure if they even take into account gender/age/weight).
I had brochitis as a child, which by adolescence and several years of treatment with inhaled steroids seemingly just settled into an adulthood of "I wheeze and my lungs just don't work well". Never saw anyone about it, just figured it was my lot.
In 2012 I had a really bad lung infection that resulted in an asthma-like attack and ambulance taking me to hospital in the middle of the night. Months of tests resulted in them diagnosing me with Small Airways Disease, which my layman brain recalls as meaning "your big pipes are fine, but your thousands of small pipes are terrible". Not much to be done medically, but they were astonished that I had at that point run a couple of half marathons and essentially prescribed "keep running!". My readings when keeping a peak flow diary were "lungs of an 80-85yo female", rather than the 35-40yo male I was. That's pretty bad: https://patient.azureedge.net/media/Default/_Profiles/4e4362...
At the end of 2016 I had reason to visit my surgery's nurse about another matter and she said "can I hear a wheeze?". A few tests later, and (apparently) some kind of threshold for one of the measurements has changed in the last few years, and hey presto: I'm officially asthmatic.
That is a lot of information to dig through. The reason it got me asking was because I thought with asthma couldn't run a marathon.
Even in my earlier year of youth when I was fit I could never run a marathon. Or even 10km. But i was never diagnosed as one with Asthma. I had always felt the air was lacking "oxygen", I am now guessing may be again my big pipes is good, but small pipes are bad.
From the paper "Replacing one hour of rest with exercise that raises the metabolic rate to seven times that of resting by, for example, jogging, removes an additional 39 g of carbon from the body, raising the total by about 20% to 240 g. For comparison, a single 100 g muffin represents about 20% of an average person’s total daily energy requirement. Physical activity as a weight loss strategy is, therefore, easily foiled by relatively small quantities of excess food."
I can't help but groan at some of the "obvious" health and weight loss platitudes that get smugly thrown around.
"Calories in, calories out!"
"You can't outrun a bad diet!"
"Weight is lost in the kitchen!"
Sure, things ultimately boil down to intake-vs-expenditure. However, it IS more complicated than that in practice. As software developers, we complain when management makes decisions based on inadequate or poor metrics. But likewise there so many more benefits to physical exercise that aren't captured by a diet and exercise tracking app.
During times when I've been 100% sedentary for long periods, I experience overwhelming cravings for sugar and crappy foods. When I force myself to take up any consistent exercise, even just a 30 min walk in the morning or lunchtime... then the cravings subside and regular meals are sufficient. This is fairly common.
Exercise has so many physical and mental health benefits. But even just looking at weight management alone, exercise tends to ramp up your metabolism for hours after each exercise session. Something that doesn't get captured by your tracker app or wearable gadget.
So often, when I hear somebody smugly minimizing the importance of exercise to health and weight management, it's a person who is too-clever-by-half. They're constantly dabbling with soylent shakes or paleo/keto fad diets... because the truth is they're just lazy and don't want to get off their ass, and look to rationalize that.
EDIT: At least half of these replies are completely missing my point altogether. I'm not saying that there is a binary choice to be made between "good diet" OR "exercise", and that you should make the latter choice rather than the former. I'm saying that treating this as a binary choice in the first place is ridiculous.
Exercise correlates with proper eating, it's not incidental or ancillary. It's ineffective to tell someone to "go the gym" without changing their eating habits? Well sure, but telling them to "go keto" without worrying about physical activity will be no more successful a year out. It's the pretense that most people can consistently stick with one of these things, and not both together, that is absurd.
I think you're misreading the function of those slogans. First off, they're hardly "obvious" when you account for the overwhelming FUD around nutrition anybody who's tried to lose weight. And you get it from everybody: your Mom, magazines, movies, the news, pop sci articles, the government, etc.
But more importantly, those things are TRUE. Anybody with significant weight to lose will not be able to out-exercise a bad diet. What fat people hear a lot more often is, "oh, you gotta hit the gym". Hitting the gym is great if you're 15 lb overweight, but at 50 or 100 it's all but useless.
> exercise tends to ramp up your metabolism for hours after each exercise session.
Yep. If you spin hard for 45 minutes you get an extra 170kcal through the rest of the day. That is... 2 fun sized Snicker bars, 19 grams of butter, or 17 Pringles chips.
Caloric intake is the absolute key to weight loss. Everything else is complementary. Telling people who are more than a few pounds overweight to hit the gym as the base of their weight loss strategy is complete un-based in science and almost always self defeating.
The worst thing you can do is to focus on calories only. That is the worst advice out there and you get it from everywhere.
YoYo effect guaranteed, cravings guaranteed, lesser ability to focus at work guaranteed and so on and so forth. And you will be miserable and won't keep it long term.
You don't just loose fat when you exercise, you build muscles, your cardio system is getting better etc etc. The way people here talk about it all sounds as if they would be putting on makeup - there is more to health and performance (including mental) then just how quick you lost few kilo.
Running at a moderate pace for 45 minutes is an easy 90-110kcal / mile depending on your weight.
Running is a double edged sword on appetite. It tends to shut down your gut for a while, making you less hungry for a period after the workout. But, people tend to misjudge how much they burn on shorter workouts or runs.
Often people only need 2 or 3 habit changes to create a long term deficit. Example: run a few times a week (30 mins, 3 miles each time, -900 kcal). Cut out sugar drinks (2 per day? -1400 kcal / day easy). One per day? (-700kcal) / week). Exercise is likely to simply make you feel better and in my experience causes me to at least think about healthy eating choices. Many people who don't exercise and drink sugary drinks can do just those two and end up with an easy 1600-2500 kcal deficit without thinking much about diet change etc. Even doing that is a huge change, and to sustain that over the course of years is a huge undertaking for anyone.
These are some simple things, yet even then most people will completely fail at a diet. A sobering statistics: http://ajcn.nutrition.org/content/82/1/222S.long -- only approximately 20% of individuals are successful at sustaining weight loss.
Personal anecdote time: I dropped about 45 lbs through calorie counting and a lot of running. Eventually the running allowed me to eat more food than I was eating before I started running. This greatly contributed to satiety and addressing the psychological and mental battles anyone faces undergoing an effort to cut fat. I have maintained the weight loss for 10+ years. It is very hard to separate where the exercise stopped and the nutritional plan started in terms of addressing all of the facets of sustained weight loss. One thing that is clear to me now is that my approach was extreme and probably only a very small fraction of people can or ever will be able to adopt such an approach. I ran at least 20 miles per week, typically 30-40, and at my weight that was for sure 2500-5000 calories per week burned from exercise alone. It put me in a position of actually having to eat more than was comfortable some days just to not push things to a relatively unhealthy range of calorie deficit. My take away is this: you can't out run a diet [^1]. I like to think of myself as "not exceptional"... I am not a fast runner and I have no real gift for it. I just like doing it. (side note: it turned out to have been very effective self medication for ADHD, so it was probably much more rewarding for me than the average person, who would probably not have the same elevated positive feelings surrounding their exercise activity as I probably get).
1: Unless you turn your body into a machine capable of obliterating calories at a rate that outstrips your ability to eat yourself fat.
Also, the whole "ups your metabolism for hours after the activity" that is factored into almost any calorie calculation and the actual burn from that is almost trivial. Its a few calories, but it is mostly your heart rate recovering down to a normal resting range. It doesn't change the basic calculations (100kcal / mile of running, etc.). You nailed that one, but people tout it as an exercise benefit when... it is just calories out and not many at all.
My point about all of this is that many slogans are correct or correct enough to be a reasonable model (calories in, calories out, can't outrun a bad diet, etc.). But the shocking lack of success in sustained weight loss is something you need to look down the barrel of the moment you decide "I will lose some weight" because if you want to keep that weight off what you are really saying is "I will lose some weight; I am going to need to make moderate to significant changes to my lifestyle... forever." It really is that meaty of a decision. Many people don't succeed their first attempt, but learn enough to succeed eventually. Most people never succeed to the degree they desire. It is because completely changing your lifestyle and mentality as an adult is very hard.
So we know all of these true things about weight loss, but I think it is a mistake to narrow it too much down to any one rule aphorism. It must be tackled on all fronts simultaneously (mental, exercise, diet). Most people will try just one and fail. Some people adopt two, but lose the habits because they weren't real change. The mental approach is the hardest to "prescribe" because each individual will have different issues and triggers for their eating. Mileage will vary, but these are some things I have observed.
You can walk. If you are at 50 + lbs of weight and haven't run at all fast walking will put you in the same cardio zone as running for a lighter weight runner. The math of calorie loss as it goes with running is the simple equation of how much weight are you moving and what cardio zone is your body operating in to move that weight. If you can hit low aerobic fast walking (most non runners can do that easily), just do that.
Beyond that I am not sure about how running impacts the joints of heavily overweight people. I would advise a very slow and conservative ramp of up mileage. I think as long as the body is given time to adjust it can do so with minimal risk of serious injury (even if you are running). The problem with running is your aerobic capacity will likely outstrip the rest of your bodies ability to absorb punishment. This is why so many "I am going to run a Marthon, but have no prior running experience" people end up injured and then wander about telling people how bad running is for your joints, etc.
I didn't even go into some of those "soft" benefits of regular exercise, such as the mental boost it gives (which seems like it would support weight loss), along with the obligatory lymph system circulation which is likely to improve immune health and help with waste cycling. As long as someone isn't overtraining, that is :)
>During times when I've been 100% sedentary for long periods, I experience overwhelming cravings for sugar and crappy foods.
This is very much a YMMV deal. I am like you in that when I train a lot my appetites for food become healthier leading me to crave more fiber and protein.
My wife, however, is the exact opposite. When she's sedentary she's fine eating whatever. When she's active and training she starts craving junk food and snacks which she has learned to use as a coping mechanism for stress.
I suspect this depends a lot about how you're socialized around eating. She grew up on processed food and her family used sweets and junk food as a rewards when she did well at things. In contrast, my mother regularly cooked from scratch and we only ever ate those "dopamine-hit" foods and snacks on special occasions so in my mind, those are more tied to times of year and social context rather than personal reward or fulfillment.
For someone who is very badly overweight, cutting calories is still a very good step. My first 100 lbs lost were from doing exactly that. After you get down to merely overweight from terribly obese is when you really need to start caring more about being active and attempting to work exercise into the routine as well. At least from my experience, cutting calories is something that beginners can fairly easily wrap their heads around that actually shows results (provided they are actually counting properly).
A couple years after deciding that it's time to get serious about taking care of my body and I'm very close to reaching a healthy weight, and additionally have become reasonably strong due to a weight training regimen. But I wouldn't be here if I hadn't seen the results of calorie counting and taken the next step after the benefits of that started slowing down.
> For someone who is very badly overweight, cutting calories is still a very good step.
It's more or less the only possible step: unless you have an absolutely freaky metabolism, exercise will not be able to mitigate an unhealthy diet until long-term (through increasing basal metabolism by building up muscle mass), and when significantly overweight it's easy to exercise "wrong" and hurt yourself.
Indeed, which is why I dislike seeing people who pooh-pooh on the idea that "calories in < calories out" is not a good first step. It's absolutely the correct first step, IMO. There's obviously more in play beyond that, but for a lot of people it's the most basic first step they need to grasp to move further down the scale. After getting eating habits under control, then people can worry more about how the body burns different calorie sources differently and balancing exercise with healthy eating.
People don't like being uncomfortable and we all actively avoid pain. Exercising at a level that significantly impacts weight loss is hard. It can be extremely uncomfortable and even painful at times. We are soft and we have a universe of terrible pre-processed foods at our disposal. It is just a fact of life that people actively avoid uncomfortable situations and so much of modern life is all about YOU being the star of your own universe and your comfort.
I think exercise and doing physically uncomfortable things consistently and at a high volume (with appropriate and healthy ramp up, of course) can shock a system into being able to cope with discomfort, the kind of discomfort required to break through previous weight loss barriers and habits. Along with understanding the problem and displacing unhealthy eating habits (and those habitual triggers) I think a lot more people would be successful at sustaining weight loss. A very small percentage of people will sustain weight loss (studies put it at 5-20%).
The sayings and weight loss facts are all missing a very large component and that is focusing on how to make weight loss sustainable per individual. No one wants to hear "You are about to embark on one of the most difficult tasks human beings in western society regularly undertake. Your chances of a failure are very high. In order to succeed you will have to learn to be uncomfortable. You will have to dedicate time and real effort to this over a course of years." That said, there are plenty of diet only programs that can sustain weight loss as exercise heavy programs.
http://ajcn.nutrition.org/content/82/1/222S.long -- This is a great look at what things are more or less successful over a longer period. One of the most interesting things is that triggers (medical events) are very good at starting and sustaining weight loss. To me this is one of those system shocks that can tilt the balance in favor of "okay, I have to tolerate this lesser discomfort now because I now I will face a much greater and debilitating discomfort in the future". Only, unhealthy eating for most people is almost always a major medical event 10-20 years down the adult road. It takes it being shoved into the forefront of the mind before people take it seriously. Anyway the summary is gold:
"Findings from the registry suggest six key strategies for long-term success at weight loss: 1) engaging in high levels of physical activity; 2) eating a diet that is low in calories and fat; 3) eating breakfast; 4) self-monitoring weight on a regular basis; 5) maintaining a consistent eating pattern; and 6) catching “slips” before they turn into larger regains. Initiating weight loss after a medical event may also help facilitate long-term weight control."
That is it. I think you need to have a plan in mind that incorporates all of these and I think from the outset they should all be a part of your weight loss habits for the most success. My own experience bears this out, having beaten the odds by (unknowingly) doing almost all of these things save for having a medical trigger (I did have a "looking in the mirror" type trigger somewhere after my first son was born and I realized I was an out of shape lazy ass that could never keep up with my kids at the rate I was going). I am pretty passionate about this topic because so much of my family got stuck in the Jenny Craight / Weight Watchers / Atkins -- just do this one thing and lose weight habit and it has never worked. I think folks on hacker news that have high enough emotional intelligence can probably work it out with just food management, but I think long term that is just as hard as trying to exercise out your bad habits. These strategies all go together to address all the areas people are likely to fail creating a safety net to prevent habit relapse.
> They're constantly dabbling with soylent shakes or paleo/keto fad diets... because the truth is they're just lazy and don't want to get off their ass, and look to rationalize that.
This is a stretch to me. Doesn't matter how much I exercise: aggressive keto diets are the only way I've ever lost weight (though not necessarily maintained it, I can maintain on a normal diet) in my life. Playing two games of full-court basketball a day or sitting around playing video games, I'm just not as hungry and the food I eat when I'm going that route just doesn't stick the way it can otherwise.
I certainly feel better, you're not wrong about that, when I exercise even moderately. But the diet matters plenty, too--it's yet another one of those more complicated in practice things that you're claiming exist in the first place.
"I can't help but groan at some of the "obvious" health and weight loss platitudes that get smugly thrown around."
On the flip side, the people that are told this are the ones that are annoyingly attempting to maintain their bad eating habits while just adding exercise, or adding fab foods, or anything really to delude themselves into thinking they can continue to eat the same way.
I have never in my life met someone who has the physical and mental discipline to exercise regularly, yet also still sits around eating candy and pizza the other 23-hours of the day.
MAYBE if you're still in school, or a new grad in your 20's, you might know people who are physically active but also like to drink heavy / party. But by the time you're 30 or so, exercise and decent eating habits tend to correlate one way or the other.
Whenever someone strikes up a conversation with me about exercise being of minimal importance compared to diet... it's usually when I'm heading downstairs for a workout in the company gym, and some brogrammer with an energy drink in his hand takes it upon himself to justify why he isn't.
I have had periods where my diet totally relapsed but my exercise never did. That is why I think (most) people need mental, exercise, and diet based strategies to lose weight. If you only use diet and that gets sketchy for a while (life stress, whatever the reason...) then your chance of relapse and weight gain are much higher. When just one piece of your strategy falls away if you still have a few other legs holding it all up it will probably stay standing.
Plus I have met distance runners with ridiculous diets. Some of them run 50 miles a week just so they can eat a pint of ice cream every week and pizza multiple times per week. It happens, but those are always at the extremes. A balanced approach is needed for most mortals.
People will justify their beliefs in a whole bunch of different ways. Until someone has actually lived it and dropped 40+ lbs and kept it off for years I immediately down grade whatever advice they are giving as they are simply less credible (unless they are well versed on the actual science and literature of the topic, in which case they likely never gained excess weight to begin with or fall into that category of someone who has lost weight and kept it off).
The number of people I have met or know personally who diet it all off with no exercise and are convinced how right they are "I lost 100 lbs!" only to balloon back to their start weight or close to it is ... a lot.
I have had periods where my diet totally relapsed but my exercise never did.
When I was going through a divorce over 10 years ago in my early 30s, I was still active (like I said in a previous post, I was a part time fitness instructor) but I ate with abandon and my weight shot up. It was easier back then - eat like a normal
person and the weight dropped.
I could do that then when I was working out 10-12 hours a week. But that wouldn't happen now.
FWIW, basic habits like you're describing will get you pretty far. Then something changes. For me, it was kids. Because of kids I couldn't get outside for the 5-10 hours I used to, and I started putting on weight. That forced me to rework how I approach eating and nutrition from the ground up.
Exercise has so many physical and mental health benefits. But even just looking at weight management alone, exercise tends to ramp up your metabolism for hours after each exercise session. Something that doesn't get captured by your tracker app or wearable gadget.
I was a part time fitness instructor for over a decade, but when people asked about losing weight, I would minimize the importance of exercise for weight loss - to the surprise of many.
Sure I ate like crap and maintained my weight, but between teaching 10 hours a week, training for runs and occasional weight lifting, I was easily burning an extra 1000+ calories a day. Most people aren't in the type of shape to burn that much in a reasonable amount of time.
Since I was being paid to workout, I was very consistent. How many people will consistently work out an average of two hours a day no matter what?
When I stopped teaching and started doing the minimum amount of exercise, I had to be much more careful about what I ate and I'm still 10-15 pounds heavier than I was at my prime.
I'm not trying to dismiss the other benefits of exercise, but weight loss isn't high on the list of benefits for most people - especially not walking or low impact exercise.
Those platitudes are also, well... Wrong. My favorite example:
> "Calories in, calories out!"
Well, sure, but those calories on the label are calculated by burning the components in a machine and measuring the heat output. The human body isn't going to convert the input food at 100%. That percent is going to depend on a lot of factors!
So? Are we assuming these things are 100% off consistently? If what you care claiming is true, there should be wide swaths of people on bodybuilding forums raising hell about how inaccurate nutrition labels are. But for anyone counting calories, it seems to work just fine.
Your point absolutely has merit. I know some, but not many, badly overweight people who exercise regularly. I know some, but not many, skinny people who never lift a finger.
I was mostly trying to address the direct cause-and-effect conclusion the parent comment was making with breathing hard == losing weight
The most important role of exercise in weightloss is hormone regulation, not the calories burned. (As you correctly point out.)
Being less stressed and routinely expending large amounts of energy simply causes your body to run differently (because of the hormones produced and burned off), which in turn changes how it processes food and fat stores, what it craves, etc.
I think proper hormone regulation is far more sustainable than the calorie restrictions necessary to offset out-of-whack hormones.
> I think proper hormone regulation is far more sustainable than the calorie restrictions necessary to offset out-of-whack hormones.
Sure. As long as you have time to work out. Or you don't get hurt. Or you can afford to go to a place to work out (much of the US isn't even walkable).
You could hit the level of physical exercise I'm speaking about in 30-60 per day at home with bodyweight exercises, with a very minimal chance of injury. (To the point my 90 year old grandmother can do the exercises -- she's just slower and does lighter versions.)
That's not a priority for some people, but that's a choice they're making.
It's absolutely not about access or time -- it's about choosing to do it or not. Frankly, given how much more efficient it makes everything else, I think it's harder not to.
The question is whether the body spends any energy outside of that hour after exercising (e.g. by growing muscle, etc.) than it would otherwise. That would make exercise more effective when considering longer periods of time.
It helps in other non-measurable ways too.
If you know you're going to go for a run in 2-3 hours, you're going to not eat an entire pizza for lunch, for example.
That quote is deceptive. An hour's jogging will burn at least 500 calories even for quite small people going quite slow, perhaps 700-800 for larger or faster ones. That would be a massive muffin and significantly more than 20% of an average calorie consumption.
A remarkable fraction of your energy consumption is spent on basic maintenance, and of the rest, far more than you'd think is spent on the brain. Your body is extremely efficient, by engineering standards, but that includes locomotion.
Exercise is still a good way to drop in weight, but not simply due to burning up the fat; that could happen anyway. What seems to be happening is that the exercise improves the body's budgeting logic, probably by putting you back in a regime evolution already dealt with.
The way to drop in weight isn't to exercise (as such), and it isn't to eat less. All the logic that says those count, is valid, but you have to account for the body fighting back. The goal is to eat less because you don't feel hungry, not despite feeling hungry. Very few have the willpower to literally starve themselves.
> The goal is to eat less because you don't feel hungry, not despite feeling hungry. Very few have the willpower to literally starve themselves.
I'm not sure if I understand this correctly, but isn't this a bad practice? I mean, I can agree with the sentiment of eating too many times per day. E.g. if you tend to eat snacks and then soon after a real meal, then you should definitely use your willpower to just skip the snacks before your upcoming meal.
But as far as I know, if you don't exercise and instead just starve yourself, the body first burns through your muscles before it gets to fat. If that's so, then some exercise is crucial to upkeep your muscles even while on a calory deficiency.
The key point is the first part of that statement, "eat less because you don't feel hungry". It's not the best worded though, but the alternative "only eat until you don't feel hungry" isn't much better since someone can feel like they're hungry when they aren't really. Also your body burns through the muscles to maintain the composition of the other muscles/hormones of your body, because muscles and fat aren't made of the same components.
> Very few have the willpower to literally starve themselves.
Yep, tried this recently with closed loop weight control. After about 8-10kg (from 116kg) lost it's almost impossible to keep on going, you can't control yourself enough to not eat.
I have lost the same amount from about the same weight in the past eight weeks or so, and will have no trouble continuing. The key (for me at least) is to eat a big lunch (around 1000 calories) of whatever you like (today I had burger and fries) and then have a couple of small snacks to a total of 200-300 calories in the evening (I'm eating a Muller corner yoghurt right now). The problem with most diets is that they starve you throughout the day, when the actual problem is habitual snacking. With this method, the most you have to wait is until the next day, when you can eat whatever you like again for lunch. Originally I intended to have a cheat day every 10 days, but I've barely needed them.
200g is what a typical sedentary person breathes out in a day.
You can definitely increase your burn rate by way more than 20% with heavy exercise. A Tour de France bicyclist will burn several thousand calories (4,000-7,000 depending on the stage and rider) in only about six hours. For comparison, a typical sedentary person will burn 2,000-2,500 calories per day. It can be physically difficult to eat enough at that rate, and riders lose a substantial amount of weight over the race. (A friend once told me about an endurance cyclist he knew who would eat a big bowl of cereal each morning, except instead of milk he'd use olive oil. Disgusting, but an effective way to get enough calories in.)
It's pretty tough for most of us to achieve anything like that much exercise, of course. Even Tour de France riders only do it for a few weeks at a time.
Not worth it. If you excercise hard for an hour daily you can triple your rate of breathing during that hour. So you get 26 instead of 24 hours of usual fat burning.
Not much of a difference. Skipping some food can do much more.
I would venture to guess that it's not necessarily just that you are breathing in out out more often, but that the composition of the air you are breathing out changes.
> composition of the air you are breathing out changes.
Apparently experiments show it pretty much stays the same. To remove more CO2 from your blood your body just breaths faster. Maybe the process of exhaling can't achieve higher concentration.
How easy it is probably depends on your circumstances.
There are infographics and whatnot out there detailing the caloric density of different kinds of food, that make it clear that, depending on the diet you already eat, you can reduce your calorie intake by vast amounts just by switching up what kinds of food you eat. But it's potentially a more expensive way to eat, and probably a more time-consuming one if you don't already enjoy cooking.
I used to believe that too. Just eat low caloric density foods, right? It makes a lot of sense. So, I calculated the precise caloric density of Everything and ate nothing but <0.8 calories/gram foods with increased emphesis on 0.2 I had to eat truely vast amounts of food to get anywhere near full. We're talking many many pounds of spinach and 8 zero calorie jellos, pound after pound of vegetables and high fiber fruits: like berries.
It does NOT work well at all. Don't get me wrong, it helps a little, but your stomach is extremely smart and it knows alot more about calorie counting than we do. Like it or not, it keeps it's own account of your calorie intake and adjusts your hunger and appetite accordingly.
If you're like me and you're already eating a very healthy diet and you exercise regularly and your still gaining weight, you only have one option: go hungry. Very hungry. Right now, it's the only way. You could exercise a lot more, but either way, you're going to suffer.
That’s also my experience. I do a lot of Thai boxing and I need to control my weight to maintain my weight class. I switched from a balanced diet to a keto diet hoping for change but at the end both averaged the same. The only difference was that with the balanced diet I had to eat twice as much food to actually feel full and work out without being dizzy. Now I am walking down the path of strict calorie intake control, trying to better understand my metabolism tipping point. Working out more has no effect if it does not come with some form of caloric restriction.
Personal experience: I've lost 4lb per months for the last 6 months with no cooking. I'm lazy so I just use microwavable food: 3mn to prepare, I know the number of calories so I can easily stay under my target.
Even with not microwaved but easily made, pre-made soups or veggies are easy to heat and more filing.
Even eating only snacks I can stay under 1.5k per day by just not eating anything on the side.
The trick for most people starting is to not drink your calories: switch to 0% calorie sodas and replace sugar in coffee and tea with aspartame. No fruit juice and check calories as "0% added sugar" usually mean there are a lot of calories.
The insight that I found to be more helpful is that if you want to count calorie losses from exercise as weight loss, you at least need to make sure that you aren't consuming more extra calories than what you burned from exercise.
It can be hard to do this if you don't have awareness over what you typically eat.
It's easier to eat less caloric dense foods than both.
I love stuffing myself full of food, and I suspect others enjoy this too.
Knock yourself out with as many carrots as you can have.
Eat a full pound or two of cauliflower.
Have you tried it? I did, it's easier only for some time. After you lose about 6-7% of your body weight it's very hard to eat less, your whole behaviour changes.
Dropped 25kg (45ish lb) 3 years ago. Gained 12kg back the next 2 years which I removed during the last 6 months. Still more weight to shed but I know what works for me and what kind of effort it requires: going hungry by eating less.
Like lot of fat-logic people I used to think that exercising was required and even the only thing needed to get fit. "I'll just start exercising and be back to an healthy weight" is just a fantasy. There is no miracle way of doing it.
I tried it - I lost nearly 25% my weight (down from 132 kg to 101 kg) over this year by eating less and walking on foot a lot more. Eating less is certainly having a lesser effect than it did at first, but I'm still losing weight bit by bit.
Walking is very underrated as exercise. People think they have to go to the gym or run a marathon for it to count.
In fact, if you're overweight, running could shoot your HR way up (+190). Try walking.
I did similar a few years ago. Dropped from 172lbs (78kg) to 139lbs (63kg) in 5 1/2 months. Near 21% weight reduction in body weight, just by counting calories and walking (granted, quite a bit). There definitely isn't a "wall" you encounter when losing weight. I tracked everything I ate (often to the gram) and it felt like little more than basic arithmetic.
Had a friend take notice, so he took it up himself. Dropped the best part of 60lbs (27kg) over the course of the year. Very different diet, but again tracked everything he ate (again, often to the gram) and lifted weights instead of walking. He was baffled with how simple it ended up being, but was pleased with himself nonetheless.
Is there statistics for this? I recently dropped 20% of my bodyweight, but didn't find that my behaviour changed at all. If anything as the routines set in it became easier.
Generally a sustained weight loss of 10% is considered to be a good target. It's the around the balance point of "real, tangible benefits" and "can actually be accomplished and maintained".
There are absolutely people who are successful at losing (and maintaining) more than that, but they are a pretty small minority.
I don't have sources in front of me, but this is based on many conversations with my sister-in-law, who is just wrapping up her dietetics internship (after completing her undergrad in nutrition). I'm sure I can get some sources from her later in the day if you would be interested.
I would be interested in reading on this phenomena. I've heard this 10% before, but didn't find there to be much of a bump myself. The diet at no point was particularly difficult to stick to once I'd developed the initial discipline. I did find my strength performance to decrease after about 3 or 4 months, but I don't know if that's due to a particular hormonal shift, or being on a caloric deficit for an extended length of time, and a general decrease in mass making lifts harder.
Trees (and other plants) are almost entirely air and water. Very little soil gets incorporated, and almost all of that is trace minerals dissolved in the water.
Curious. I've heard this about trees. What about tomatoes? Cucumbers? etc? Or is this comment only referring to the "substance" of a plant and not its fruit(or similar)?
It applies to fruit and similar. All the sugar and other carbohydrates are air+water primarily. There's a bit of nitrogen from the soil, and everything else is extremely small trace elements. Carbon, Hydrogen, Oxygen, Nitrogen (CHON) are the four most common elements in all Earth life. Plants get the hydrogen and oxygen from water, and carbon (and more oxygen) from CO2 in the air. Cellulose is CHO only. Same for glucose, fructose, etc. Nitrogen is mostly found in the proteins, with a bit in DNA, RNA, and ATP. Humans are about 3% nitrogen by mass, plants are a bit less (lower protein concentration).
I was under the impression (admittedly I don't know from where) that the process of burning fat actually dehydrates you and that you need to drink extra water if you want to facilitate it.
But here you remind me that the process of burning hydrocarbons nets some water, making me question myself. Of course metabolizing body fat is more complex than that, so this doesn't disprove it, but now I'm wondering if anyone else has more concrete information.
Dont forget that you need to cool your body, so you sweat when you work out. Also, as you breathe harder, you'll loose more moisture through your lungs (the water activity of your whatever parts in the lungs being higher than that of dry air.)
If you were to exercise outdoors during a cold rain, you'll probably not loose any water at all.
But what do I know? I've never exercised in my life.
I respectfully disagree. The only reason I didn't use the word "clickbait" is because it's apparently the actual title of a scholarly paper. A lot of the titles that turn up in your search are what I'd call clickbait.
I've been posting here for years and this is the first I've heard of it. It doesn't seem like a very important part of the site's culture. Or maybe I'm just oblivious, it's possible.
The difference between answering the title and writing a tl;dr is that the former doesn't use the character sequence "tl;dr." Apparently this is important. From your first link:
> PeterWhittaker's comment is fine without the "tl;dr". The concern is the symbol—symbols matter.
I'm a bit confused as to what happened in the second link. Going up the comment chain, apparently the original title spelled out what happened but was editorialized, so it got changed, and "There's a downside to spelling things out completely" was part of the explanation of why it was OK to switch to a less editorialized title with much less information in it. Yet the title of the post is the one they said they changed. Did they change it back later?
It seems worthwhile to preserve the bookishness of HN. One of the best ways to do this is to make HN seem boring. Reading, writing, and good conversation take time and effort.
"For anyone coming straight to the comments looking for an answer to the question:" seems like a macroexpansion of "tl;dr:".
Of those four results, the first one is explaining why they don't want author names in titles, the second one explains why they like minimal design, the third one was a false positive on "attention-grabbing Unicode glyphs," and finally the fourth one actually talks about the topic at hand. Why not just link to that one?
The fourth one places a lot of emphasis on the specific implications of "tl;dr" as opposed to other terms like "summary." Given such precision, I'd say the macroexpansion of "tl;dr" would be "too long; didn't read" since that's what it actually stands for.
I'm persuaded that "tl;dr" is best avoided. I'm not persuaded that my comment would or should fall under this guideline.
I sometimes ask the deep philosophical question, why does a tree not sink into the ground it grows out of? It blows people's minds when I explain that the reason is because the tree is mostly water and CO2, a gas and a liquid coming from the sky.
Trees don't sink into the ground because (a) a tree's root system is as large in the ground as it stands out of the ground and (b) the pressure of the weight of the tree is distributed across the (large) surface area of that root system.
Trees aren't light, by any stretch of the imagination. That solid mass is mostly water. Try lifting up a 1' or 2' section of a tree trunk that's 1-2' in diameter sometime.
The water is the vast majority of the overnight weight loss. pCO2 of 40 mmHg is normal. Resting tidal volume is 500-600 mL, and a breathing rate of 12-14 (officially 10-20, but really, more like 12-14). I'll let someone calculate the mass of CO2 exhaled in 8 hours.
The article claims that 200 grams/day lost as carbon in CO2 is typical. (The oxygen comes from breathing in, so doesn't count for anything.) That implies that the amount lost in eight hours of sleep is somewhat less than 67 grams.
According to the article, a typical person will breathe out about 200 grams of carbon per day. (The oxygen in the CO2 comes from oxygen you breathe in, so doesn't contribute to any net weight change.)
A pound of fat is about 3500 calories, and typical sedentary metabolic rate is about 2000 calories per day, so you'd expect to lose about 0.57lbs ~= 260 grams per day if you didn't eat. The article says that CO2 makes up 84% of weight lost (the rest is water), so that fits fairly closely to the 200 grams/day of CO2 breathed out.
Thunderf00t had a great take on this showing why excercise is pretty much useless for weight loss.
You exhale same percentage of CO2 no matter how active you are so to burn more fat you have to make yourself breathe faster. You can do that with excercise which, if it's intense, can triple your rate of breathing. But if you do intensly excercise for an hour each day you just burn 26 hours of fat instead 24.
Not much of a difference. You can do much more with skipping some snacks or soda you ingest daily.
The food you eat will turn to CO2 one way or another. If you let your food become fat rather than CO2, that fat will eventually turn into CO2 after you die.
Merely breathing faster won't help. Each breath will just remove less CO2. What you need to do is produce CO2 faster, which means increasing your metabolic rate somehow. That generally means exercise.
That is a form of exercise, so in that sense yes. It isn't significant, even on the scale of a year, but it is something we can calculate.
For practical purposes no. When you breath faster your body just gets rid of less CO2 per breath. The amount of CO2 your body creates for a given exercise level can be considered a constant.
That's a matter of liver health, right? So you could theoretically go higher (by combining antidiabetic drugs with beta-adrenergic agonists, and then sitting in a hospital in a cold water bath hooked up to a liver dialysis machine.)
Not a viable alternative to dieting and exercise, of course, but maybe an alternative to liposuction or gastric-bypass surgery.
I'd suspect the more exercise you do the more that number moves up, you'd be breathing harder. I'd hesitate to try and put a 'hard limit' on anything like this.
A colleague who was into serious mountain climbing said that at 5km it was not enough to eat like 5000 calories per day to maintain weight. He even on purpose gained weight before his trips, and still returned leaner despite eating a lot.
Like the previous commenter mentioned, that's mostly water. I've seen various numbers between 100 and 150 calories burned per mile for runners, which at the high end is just a bit over one pound's worth of calories for a marathon.
I’ve read about people who do things like swim the channel, and bulk up (10’s of lbs) before doing so. Given that they lose this weight in the process, how does that happen?
I think that's mostly independent. A swimmer bulking up for a channel swim is probably putting on a mix of water, fat, and muscle in the slow lead up to the swim (and maybe extra water in the days before) and then losing water during the swim. Here's [0] a discussion of swimmers strategizing about weight gain, and you can see that it's largely about issues like insulation from cold, buoyancy, and strength, and not because they're worried about losing the weight during the swim itself.
"Strong likelihood" only in cases of extreme dehydration. Many wrestlers/ boxers will drop >5 lbs in one day with no longer term impact. The majority of that being water weight they gain right back again.
Well, but you also breath in the O2 first, I think the C just binds to that. C and O weigh similar amounts so it is just 1/3 of the 2 pounds. But you have to count the water loss as well, it is part of fat cells.
How many calories can you max burn per day, around 8000? That would be ~1.1kg of fat loss at 7 kcal per g fat. At a normal day of not eating it is ~300g afaik (2100 kcal at 7kcal/g).
To have such enormous deficit you would have to exercise a lot. And of course you breathe faster during the workout so I think it is entirely possible to breathe out more than 2 pounds of CO2 per day. 2 pounds if probably average for a typical person.
Because it's not that simple. Every moment of a person's life adds to their sum total of knowledge but it's very limited. Simply being a living human isn't going to give you a good understanding of quantum mechanics or general relativity, but it will give you some basic idea of things falling towards the ground. Something being unintuitive doesn't mean just that the individual lacks knowledge but that there is very little chance that this knowledge would be encountered in ones life time at all without making an effort to gather a deeper understanding.
I once saw a documentary about "big animals" in the past.
Like, why did we have giant spiders and insects while they have a rather simple respiratory system that doesn't scale very well.
Because: trees!
Somehow plants managed to create wood, which bound the C from CO2, but the rest of the biosphere didn't know what to make of the wood. So there were more and more trees and more and more C got removed from the atmosphere. A much bigger part of the atmosphere was O2 and so the insects could grow bigger.
But in the end the fungi figured out how to make short work of wood and in turn released much of the C again into the atmosphere as CO2, so the animals shrunk again.
okay - thanks. Years ago someone told me a story of the ants saving us from a wood death, and I never checked it out, but recounted it just the other day. Fungi seems more reasonable on reflection.
> That is very interesting. Is it related to coal? Will the trees today nor form coal because they will be processed by fungi?
No, coal has formed after fungi found how to break down lignin (lignite is usually "young" coal, having generally formed between the disparition and the dinosaurs and modern day, generally speaking the better the coal the older it is as coal is a metamorphic process, so given similar conditions time is the factor for the rock going through the grades), lignin isn't the only organic component even in carboniferous coals, and these coals have lignin-rich and lignin-poor epochs and locations. And peat lands exist today which perform the first "step" of coal formation.
The trees today are unlikely to form coal because that first requires quickly putting the trees in anoxic conditions (e.g. acidic waters or low-permeability soils) over a sufficiently long time that good-sized layers can build up, then shifting those layers way down so they can be converted by heat and pressure over millions of years.
Carboniferous had lots of low-lying forested wetlands and swamps which provided the vegetable matter in anoxic conditions, and the subduction zones of the forming pangea proceeded to shove much of it under (when both happened in the same place), that is why it's the source of so much coal.
But few of our peatlands are in subduction zones, and even if they were it's unlikely we'd give them the time to accumulate and slide down for processing.
> Physical activity as a weight loss strategy is, therefore, easily foiled by relatively small quantities of excess food.
> Our calculations show that the lungs are the primary excretory organ for fat. Losing weight requires unlocking the carbon stored in fat cells, thus reinforcing that often heard refrain of “eat less, move more.”
"Eat less, move more." If anyone isn't aware of that by now, I don't know what to say.
the eating less part is more important (for weight loss) than the moving more part, especially because people doing exercise for weight loss often overestimate how many calories the exercise is burning, and underestimate how many calories are in food.
Plus, the difference between "not losing weight" and "losing weight" can be a lot of calories.
If you were gaining weight regularly and start exercising to lose it, you'd have to do a ton of exercise to compensate.
But if you're on the verge of losing weight and start exercising, it would be possible to tip the scales, so to speak. So long as you don't start eating more because of it.
I'm 205 lbs, and the charts say I need to eat between 1500 and 1800 calories per day to lose weight. I can eat 2600 and maintain my weight.
So if I'm just barely maintaining my weight at 2600 calories and I want to lose weight, I'd need 800 calories worth of exercise.
Moderate-pace walking burns 300 calories per hour for me. I'd need almost 3 hours of deliberate walking at a good pace to lose that extra weight, every single day. And I couldn't reward myself with a treat afterwards.
I got the exercise numbers from MyFitnessPal. The food calories I got from a site I found the other day, but I don't remember which.
Yeah, it's more like body composition than 'weight loss', most people want more muscle / less fat, and then eat a diet that produces more fat and less muscle.
People act as if Arnold got his body by once accidentally picking up a barbell, then eat a bunch of food that immediately gets converted into fat and wonder why running on a treadmill to destroy their muscle & eating sugar to produce fat isn't giving them the results they want.
TFA does say "energy/heat + CO2 + H2O", but most of the output in terms of mass -- which is what one is interested in when it comes to losing weight -- is carbon dioxide.
The fat molecules burned usually have about twice as many hydrogen atoms as carbon atoms so you end up with about as many CO2 molecules as H2O molecules. Carbon weighs about 14 times as much as hydrogen and most of the oxygen in both comes from the atmosphere. So when you lose weight, 7 parts go to CO2 and 1 part goes to water. A very very tiny proportion goes to energy with mass-energy equivalence.
Chemical reactions undergo the same mass loss as nuclear reactions. A fat molecule weighs very slightly more than the sum of it's parts. The resulting water and carbon dioxide products will weigh less than the reactants by exactly the amount of energy released. It's just much more difficult to notice because the amount of energy released is as much less.
I've heard of this as well. However, I assume this means that mass turns into kinetic energy specifically, right? And potential energy actually increases with mass? (This isn't something I've heard, it's just the only way I can make sense of things.)
Is this true? I was under the impression that the excess energy is due to the different bond energies of the input and output molecules and not due to mass to energy conversion.
The mass that's converted to energy in both chemical and nuclear reactions comes from differences in bond energies. Nuclear chemistry is about the bonds between subatomic particles, ordinary chemistry is about the bonds between atoms.
Mass-energy conversion isn't a special thing, it's universal. All energy has mass. When energy moves, mass moves, always.
I'm reasonably certain that this is not correct; this was a viewpoint held fairly briefly in the post-Einsteinian physics community, but abandoned because of a lack of evidence.
For the purposes of general relativity, stress-energy is the mass/energy hybrid quantity, but the equivalence is not literal in the sense that in a given inertial reference frame momentum does not attach to energy, but only to mass.
Converting mass to energy does not violate conservation of mass. But if anybody on the planet managed to convert a pound of mass into energy, we'd hear about it pretty quickly - it's roughly as much energy as a Castle Bravo thermonuclear weapon released. But chemical reactions of course do not involve any significant change of mass, too low energy levels.
It's pretty obvious when you do long fasts.
Every time I fast for more than I week, I lose several kilos doing nothing, not going to the bathroom even once except to pee.
Their point, which I agree is fairly unclear, is that the fat is not converted to energy, it's converted to CO₂ and water. That conversion releases energy, which you then use to move, but the total mass of the process is constant (conserved).
Just to add a bit of clarification, the excess energy part of the equation is coming from the energy stored in the chemical bonds of the original molecules.
The chemical energy of the original molecules is more than the chemical energy of the resulting molecules leaving some energy to do work and to generate heat.
That release of energy does result in mass loss. e=mc^2 as everybody knows, without understanding. However the energy is fairly small, and c is already extremely large before you square it. Over an entire lifetime the mass loss is still insignificant.
> Most people believed that fat is converted to energy or heat, which violates the law of conservation of mass. We suspect this misconception is caused by the “energy in/energy out” mantra...
I would not call it a misconception but simplification. Otherwise it is a very surprising article.
Observations from Figure 1, "Responses of a sample of doctors, dieticians, and personal trainers to the question “When somebody loses weight, where does it go?”"
Overstating the case about “0 dietitians ... only dietitians.” It looks as though about 2 people thought sweat was involved, and only 1 dietician answered co2. Pretty much everyone answered “heat.”
The question itself is shit, too, which is what happens when you dont have survey epidemiologists eyeball your questions. In “losing weight,” you’re doing a number of things - chucking the actual carbons (mass), and removing the potential energy stored as carbon-carbon bonds (heat). Given the widespread colloquialism of “losing weight,” people failing to interpret it as regarding the removal of carbons specifically isn’t unreasonable.
Sweat and urine are also correct answers, for that matter. Some of the carbon is used to create bicarbon and carbonic acids, via co2, which are lost in urine and sweat. Whether you want to count that as co2 or not is an argument about semantics - it goes through co2, but isn’t lost -as- co2. Of course, from the perspective of “it’s all breathed out as the result of perfect oxidation,” it’s wrong... but why let biology get in the way of undergraduate chemistry, right?
This isn’t a reflection on docs, PTs, or dietitians. This is GIGO.
At the risk of crossing the streams here... “wait! HN must be listening to the Microphone on my phone because I talked with my son about this exact topic 36 hours ago and now it’s in my HN feed!”
Yes, that’s a joke, but it’s also a completely factual statement (except for the Microphone thing) and a good reminder that with enough page views even extremely low probability events will happen with great frequency and predictability to someone in your audience (you just can’t predict to whom they will happen)
You ask an ill-specified question and get an ill-specified answer. Of course that fat "goes into" energy/heat, it says so right in the oxidation process.
It's an interesting reiteration of HS chemics, but of no practical concern.
When you realize that you have to breathe out all the weight you lose, I think it gives you a bigger appreciation for how difficult weight loss can be.