As someone deeply involved in the weight loss space (CEO of Alfie, men's health starting with weight loss), I would not recommend biology "hacks" to lose additional weight. Hacks often result in a series of other physical and sometimes mental harm. The best ways to lose weight are dietary changes and exercise, in some cases combined with medication for individuals who have struggled to lose weight via lifestyle changes alone.
Additionally, weight is lost mainly as CO2 because of the metabolic processes that convert fat into energy and this process' byproducts ~(84% CO2 and 16% H2O). Additional O2 intake would not cause your body to burn more calories, and it's unlikely this strategy would result in passive weight loss.
Additionally, weight is lost mainly as CO2 because of the metabolic processes that convert fat into energy and this process' byproducts ~(84% CO2 and 16% H2O). Additional O2 intake would not cause your body to burn more calories, and it's unlikely this strategy would result in passive weight loss.