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There's no doubt that biology strongly influences the risk of becoming obese. Evidence for reduced energy expenditure being involved is much weaker than for variation in control of appetite. Not sure that the results of the fasting studies cited below support the latter / https://twitter.com/AbdTahrani/status/1360711433739243521
e.g. Take an obese person with 60Kg lean and 40kg fat and a lean person with 60kg lean and 10 kg fat and deprive them of all calories. Glycogen will disappear rapidly and they will both burn fat (9 kCal/G) at rate determined by the largely by their lean mass /
So if they both burn off 5g of their stored fat the obese person will have lost 5% of their body weight and the lean person will have lost 7%, with no difference in their rate of fat mobilisation. (would be good to have @JohnSpeakman4) thoughts on this thread /
with prolonged starvation a real difference will emerge as the lean person will deplete their fat stores earlier and start to burn stored protein which only provides 4kCal/g, so will start to lose body mass more quickly than the obese person who still has some fat to burn
Its a bit of a distraction to be looking for the causes of obesity in different rates of energy "burn". The genetically programmed differences between ppl that predispose some to obesity largely exert their effect in the brain.
This means that susceptible people tend to eat slightly more calories on a day to day basis than they expend through processes that are largely subconscious. There is no evidence they have a general "lack of willpower" as workers, citizens, partners, friends etc.
Semagluide (works only through appetite) is a great example of how beneficial it can be to help obese people reverse caloric imbalance through long term reduction of daily food intake through means that do not require obsessive conscious attention to every morsel they eat
