How do you lose weight while in a foot cast?

Eat less . Being in a cast in an indication that your doctor doesn't want you working out. The doctor is trying to protect your surgical sight. My recommendation is to eat fewer carbohydrates and if you work out, work out your upper body. Remember if you get to sweating, that cast is going to absorb the odor and that can be an irritant given enough time. Your weight gain is also only temporary.