It isn’t surprising to most people that getting a good night of sleep is important for weight loss and maintenance but I think it’s important to understand just how important it is and why this is the case. Sleep is one of my favourite topics to discuss with patients because almost everyone could use some improvement in this area. A lot of people want help with weight loss but before turning to extreme diets I prefer to take smaller sustainable steps and optimize diet and lifestyle. In this blog I would like to address some eye opening facts about how a lack of sleep can set us back:
A study was performed at the University of Chicago looking at how sleep affects weight loss. All participants were put on the same calorie restricted diet – This means that in theory everyone in the study should lose a similar amount of weight. One group was allowed to sleep 5.5 hours and the other group was allowed to sleep 8.5 hours. It turns out that the group who slept 8.5 hours lost 55% more weight than the other group. In addition, the sleep deprived group reported feeling hungrier than the full night of sleep group.
But why does this happen?
Hormones! When sleep is limited there is a decrease in weight loss promoting hormones and an increase in hormones which promote weight gain.
Weight gain hormones: When we are deprived of sleep the hormones cortisol and ghrelin increase. Cortisol is a stress hormone which has many effects on the body but the most relevant here is increased storage of fat. The other concerning hormones is ghrelin which is considered our hunger hormone. It stimulates hunger and promotes fat storage.
Weight loss hormones: During sleep deprivation we see lower levels of the hormone leptin. It works opposite to ghrelin meaning that it tells us we are full and decreases hunger signals. Finally, with less sleep there is less melatonin produced. We don’t normally associated melatonin with anything besides sleep but it turns out it has important actions on brown fat. Brown fat is different because it is activated when we are cold and promotes fat burning rather than white fat which is for fat storage. It appears that melatonin can help increase these levels of brown fat which is important for weight loss.
Stay tuned for my upcoming blog discussing lifestyle tricks to improve sleep quality.
Dr. Kelsey Murray, ND