Every time I went to the field, living on MREs and getting garbage sleep, I’d come back feeling like I’d lost all my muscle. Nothing will make you feel more skinny fat than an extended trip to the field. But it always came back fast, and there’s a reason for that. Short trips to the field or a week of being sick aren’t long enough to erase the muscle you’ve built. What’s really happening is mostly glycogen and fluid loss. You’re not training the same, you’re under-eating carbs, your muscles burn