Sure, but some might be genetically predisposed to make more efficient use of calories (burn easier rather than store as fat). Which could make a massive difference.
It is a huge difference. But, it doesn't matter. Some people can eat more than others and not get fat. There is no justice in the universe ;-). Whether it is some gene, your body size, your age or something else, it doesn't matter. Eat too much and you will get fat. Don't eat too much and you won't get fat.
That last bit is super important. There is no illness that causes people to starve to death even when obese. Your body is a factor, not an excuse (Ha ha! Here I am quoting Arnold!)
Just invent flying cars, that will solve some problems. Easy, right? The "HOW" is a problem, not "what is needed". When obese people don't eat too much, their body thinks "I don't have enough, time to enter energy saving mode and increase hunger".
Of course it'd be better I'd you could just read it off neurons, too hard though.
Hormonal imbalance caused by overeating was in my case worst than the hormonal imbalance caused by lessening the amount of food i ingested, so it wasn't this hard to stop. Also my life improved a lot around that time (credit, job, appartment, relations), this might have helped too.
But correct that it might be genes was observed in the dutch population generations after early nineteen hundredth's famine crisis: [ https://www.nytimes.com/2018/01/31/science/dutch-famine-gene... ]. This eventualley led to a new area of study called epigenetics (of which one of the pioneers actually earnes a Nobel's Prize I think). Epigenetic research has shown that genes are not final. In the case of the dutch famine, the famine-victims which survived had undergone epifenetic changes (their genes changed) in response to the famine, their body would become extremely energy efficient and their energy partitioning would lean towards buildup of adipose tissue (fat). However (!!) research later shown that these gene alteration which their offspring inherited and which were observed throughout the dutch poulation generations later, was reversible by environmental factors and exercise.
Only if they eat as much as someone who uses calories less efficiently. Which is not a given.
I would think that it is highly dependent on what you're burning the energy for... Surely if you eat more to maintain a fit body/lifestyle, it is likely to have a more positive effect on lifespan compared to eating less and living a more sedentary life?
Of course, an optimal balance needs to be struck between the two, but I am very curious on what the research says about this balance.