Sleep deprivation can signficantly slow down weight loss. If you are not getting enough sleep, you body can go into emergency mode and slow down your metabolic rate. It is as if you are a caveman on high alert, under seige, and you cannot leave the cave. Under stress and sleep deprivation, your body can slow down, so you don’t need as many calories to survive. Make sure you are getting enough sleep each night, if you want to lose weight. You already know how many hours of sleep you need to feel at your best. The average adult requires 6-8 hours.