system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How does the body become heavier when you exercise for the first time in a while when you should be losing weight?
gpt
It's pretty much a collection of some water weight that then gets shed. You still will lose weight as you lose fat content, but for the process of muscle usage to occur, water is needed for those chemical processes. Glycogen fuels the body during exercise, and needs water to bind with and generate energy for muscle use.