Saying "Calories In Calories Out" is what makes you fat is as interesting as saying "Money In Money Out" is what makes you poor. It's tautologically true but doesn't help anybody.
But it's the fundamental, most basic truth. If there is anything that people who want to lose weight should do, it's eat less . Skip the snack. Smaller portions. That's incredibly hard to do, of course, and easier said than done, but ultimately it is behind virtually all successful weight loss. What is behind an enormous number of failed weight loss attempts are waving that away and believing some specific macronutri…
And what about non-humans? Animals are getting fatter, too [2]. Some of this can be explained by humans eating more, hence making more food available to those animals that eat human leftovers or steal human food. But this weight gain has also been noted in laboratory animals which are on controlled diets.
[1] https://www.theatlantic.com/health/archive/2015/09/why-it-wa...