eli5: How are many male prisoners very muscular whilst in prison despite prison food often being very poor and small?

Question

Doesn’t make sense to me as many prisoners have said that meals are “about as big enough for a 5-year-old” and often are lacking in healthy elements

In: 24

Answer 1

Prisoner opinion on nutrition isn’t valid data. Also, you can get more calories than the meals being served by various means – swapping portions, favors, commissary, brown-nosing, etc.

The main reason is that prison is BORING and working out fills the time. So many inmates work out a lot.