system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do some medications cause weight gain?

In the case if you are eating normal amounts of healty food as you were before the medication? Isn't your body starved of energy if all is stored in fat tissue?
gpt
Some medications greatly increase hunger. Others make you feel more lethargic, making you less likely to exercise, or making your exercising less effective. And some can actually affect the process of how your body burns calories, or how they store and absorb sugars and other nutrients.