Weight gain and loss is much more about biology that "just eating less". There are significant genetic and metabolic factors that contribute to each individuals' appetite and ability to control that appetite.
The stigma around weight gain has been reliant on this argument of overeating for so long, while the research has indicated that there's a lot going on behind the scenes that has to be considered.
"obesity is innate, that weight regulation is not governed by a uniform tally of “calories in–calories out,” and to quote Jules Hirsch, that “there is a biochemical or basic biological element in what it is that we call `willpower.'”5 The views of many Americans notwithstanding, weight is clearly far from being entirely within an individual's control. Genetic predispositions, in tandem with the development of food environments that facilitate overeating and built environments requiring minimal energy expenditure, may help explain why so many Americans are obese today."
I don't doubt that there are genetic and biochemical factors which rule how much we desire food and how often we'd like to eat. I'd go as far as to say nearly every impulse we have can be traced back to a genetic predisposition, one of our greatest gifts as humans is our ability to fight our genetic impulses.
I really love recreational drugs, cannabis and cocaine especially, and I'd hazard to say that part of the reason I enjoy them so much is due to a genetic predisposition. It takes a tremendous amount of willpower for me to control when I use and how much I use, while other people I know can smoke or party once a year and never feel an inclination to otherwise.
I don't think coddling overweight people and telling them that they're only overweight because of genetic and metabolic factors is anymore beneficial than telling an alcoholic they're only addicted for the same reason. Everyone has a cross to bear, and while some are heavier than others, I think it's defeatist to tell people that their obesity (or their addiction) is an innate part of who they are, not a challenge they can overcome.
Obviously I'm no expert, these are just my individual thoughts.
The major difference between your vices and overeating is that you don't need to have some cocaine every day to live. Total abstinence is not an available option for food.
That's a good point, they're definitely not equivalent. If it was societally expected of me to have three small bumps of cocaine every day, I'd have an incredibly hard time not overdoing it.
The stigma around weight gain has been reliant on this argument of overeating for so long, while the research has indicated that there's a lot going on behind the scenes that has to be considered.
"obesity is innate, that weight regulation is not governed by a uniform tally of “calories in–calories out,” and to quote Jules Hirsch, that “there is a biochemical or basic biological element in what it is that we call `willpower.'”5 The views of many Americans notwithstanding, weight is clearly far from being entirely within an individual's control. Genetic predispositions, in tandem with the development of food environments that facilitate overeating and built environments requiring minimal energy expenditure, may help explain why so many Americans are obese today."
https://www.nejm.org/doi/full/10.1056/nejmp1400613