system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5:How does vyvanse boost your metabolism if it causes you to eat less throughout the day which would slow down your metabolism?
gpt
It doesn't boost your metabolism *by* making you eat less, it boosts your metabolism *and* makes you eat less. 

Amphetamines kick your body into high gear and make you move around, increase your heart rate, boost muscle movement, etc. This is what "boosts" your metabolism. (think of running a car in a lower gear while maintaining the same speed. There are more RPMs doing the same amount of work) The loss of appetite is simply a side effect.