I'm not on GLP1 agonists or TRT. I eat primarily legumes, grain, and dairy. I don't go to the gym. I lift using $30 resistance bands and get my cardio from running and a rowing machine that I used my annual discretionary budget on. And I don't need the rowing machine. He's right.

Humans do homeostasis very well. If you stop exercising at all ("rest days"), your brain normalizes that and creates inertia against resuming exercise. Like all good habits, the point is to make it automatic and the default rather than a choice.

Once you start exercising and make it a non-negotiable daily habit, it becomes progressively harder to stop exercising than to start. Most people that fall out of exercise habits do so primarily because of injuries rather than the failure of the habit itself. You just have to prioritize it ahead of or even alongside other habits (e.g. exercise while watching TV, take the stairs) until it becomes automatic.