California pens have had no weights since 1993- other than a few plates and dumbells in Fire Camp. The free meals offer marginal nutrition but you can supplement with powders and tuna from the commissary, along with extra eggs/beef from friends in the kitchen.
With a little effort and $75 a month, you can have a solid bodybuilding diet in the joint.
Actual prison diet:
Meal 1- large bowl oatmeal or grits w/butter, two pints low fat milk, cheap wheat toast 3-4 slices, handfull of amino's
Meal 2- 2 cans tuna, 4 slices of cheap wheat bread, piece of fruit
Meal 3- protein shake (medium sized) 30-40 grams (Champion Nutrition powder or something else decent from the commissary)
Meal 4- 1 or 2 medium sized, poor piece(s) of beef or chicken, rice or pasta, large salad, piece of fruit
Meal 5- 6-8 egg whites with 4-5 yokes, as a drink
This was an actual working diet. How do I know? I know.