The gist of the video is that the brain is a really powerful regulator of how much energy you use. Do a ton of exercise and it’ll find energy savings elsewhere.
But as you build up muscles you constantly need more, even when not doing anything
Each human has an amount of calories they burn even when they do nothing (the amount of calories you burn obviously goes up when doing things)
This basic calory burning or whatever it’s called in English is influenced by a few factors, one of them is how much muscle mass you have, those muscles need energy to simply exist, even when not exercising.
So people who regularly do sports indeed can eat more - they not only can eat more, they have to eat more (even when they do the exact same things as someone with less muscles)