That assumes you would be eating more to compensate for the activity. Many people, because they spend so much time in their car or just being sedentary otherwise, actually need to go out of their way to exercise (e.g. in a treadmill in a gym). And for people who don’t already exercise, the marginal increase in CO2 is probably worth it for society.
Practical example: I primarily walk and cycle, used to have a car but no longer do. I need to get 1-1.5 hours of walking in a day for my health. I chose walking because it is specifically calorie inefficient and unlikely to make me hungry like running or cycling.
If I can walk for all my business, I no longer need to take a separate walk in the evening to get my exercise. If I drive a car or ride the e-bike (the e part robs you off fitness benefit) I now need to take a separate dedicated walk.
If you consider that the CDC wants every American exercising several hours a week, I think your friend’s analysis would come out differently.
Also the analysis should factor in the reality that walking 6 miles will likely not trigger the same level of calorie intake increase as running or biking 6 miles; it is very easy to e.g. run and actually consume far more than you burned due to appetite response.
If you’re trying to lose weight (I am), or not gain weight in a western culture that encourages a high level of consumption, you want something that is inefficient.
I can get from point A to point B faster and with less energy expenditure (I think) on a bike.
Theoretically running is even more inefficient (depending on speed apparently) but I hate doing it and it spikes my appetite in a way that makes dieting unsustainable. Maybe it’s genetic, I remember my dad going through a phase where he ran enough to the point where he could do a half marathon while obese; he easily consumed more than he burned despite a very heavy training schedule.
I can walk for 30 minutes, an hour, two hours, or almost literally all day and still eat less than I use which is extremely efficient for my goals but extremely inefficient at making me fat.
Practical example: I primarily walk and cycle, used to have a car but no longer do. I need to get 1-1.5 hours of walking in a day for my health. I chose walking because it is specifically calorie inefficient and unlikely to make me hungry like running or cycling.
If I can walk for all my business, I no longer need to take a separate walk in the evening to get my exercise. If I drive a car or ride the e-bike (the e part robs you off fitness benefit) I now need to take a separate dedicated walk.
If you consider that the CDC wants every American exercising several hours a week, I think your friend’s analysis would come out differently.
Also the analysis should factor in the reality that walking 6 miles will likely not trigger the same level of calorie intake increase as running or biking 6 miles; it is very easy to e.g. run and actually consume far more than you burned due to appetite response.