There's one paradoxical-seeming fact that adult humans generally use the same amount of calories each day regardless of their physical activity level. There are exceptions, but they are extreme cases, like professional athletes pushing their limits.

It makes sense if you think about it. Processes that give us access to energy aren't exactly fast, so our bodies will just be producing that energy regardless so it's there if we need it. But when we don't, any cells can grab them up to do their cell things, which includes cancer cells (which we all have but are mostly benign), giving them more chances to make more mistakes copying DNA, which rolls the dice more often on picking up some of those mutations that make them dangerous or deadly.

It's also why you lose weight in the kitchen rather than the gym. Your body isn't doing anything differently with the food you eat whether you take a nap or go for a run.