>>11576854The more calories expended on lifting heavy stuff, the less calories available for studying. Your internal calorie calculator will do literally everything in its power to ensure this, that the least calorie-expensive path is always the one you're taking. You've evolved for this and every single on of your ancestors who devolved a tiny bit of it got filtered. Just look at any math phd, the handful of people who're both fit and have a phd have most likely lived a stoic life and will crash hardcore in their 30s as the debt cycle of their calorie expenditure hits the peak. All the others are dyels.
Now is exercise good? Of course it is. Is it better than expending calories on something else? That's the question you should be asking.
