See my more extensive answer below—I’d propose the reason for the obesity epidemic is constant effortless access to highly processed high calorie, low satiety foods, with zero need to move. With human genetic make-up, the automatic response to that is overeating calories and hence obesity unless one intervenes to resist the impulse (indeed hard to sustain, albeit not impossible—anorexia is a thing), or changes one’s immediate environment (e.g. the food one keeps in one’s home and one’s movement routines.)
See my more extensive answer below—I’d propose the reason for the obesity epidemic is constant effortless access to highly processed high calorie, low satiety foods, with zero need to move. With human genetic make-up, the automatic response to that is overeating calories and hence obesity unless one intervenes to resist the impulse (indeed hard to sustain, albeit not impossible—anorexia is a thing), or changes one’s immediate environment (e.g. the food one keeps in one’s home and one’s movement routines.)