1. Your sleep affects your “hunger hormones”
Feeling hungry or full has a lot to do with two hormones: ghrelin and leptin, both of which are affected by sleep. Ghrelin is “snacky” – it makes you feel hungry. When you are sleep-deprived you produce more ghrelin. Leptin is the opposite: it’s sends that “I’m full” signal that makes you want to stop eating. And when you’re lacking sleep you produce less leptin. More ghrelin (“snacky”) and less leptin (“I’m full”) means, you guessed it, you gain weight.
2. When you’re sleep deprived, you burn fewer calories
You know that energized, vigorous feeling you get after a really good sleep? It’s real: when you’re getting enough good quality rest, your metabolism is higher (meaning you burn more calories, even while resting). A 2010 study by the American Journal of Clinical Nutrition found that people who got enough sleep (7.5 to 9 hours per night) burned about 5% more calories per day than their tired counterparts. The same study showed chronic sleep deprivation lowers your metabolism, impairs how your body processes glucose, and even increases your risk of developing type 2 diabetes.
3. You crave junk foods more when you’re tired
When you’re not getting enough sleep your tired brain is swimming in cortisol, the stress hormone which increases your appetite and may be the cause of the sugar and salt cravings you experience when you’re tired. Researchers at UC Berkeley found that after a sleepless night, the decision-making frontal lobe portion of our brains is impaired, while the reward centre is stimulated, causing you to crave calorie rich foods like doughnuts, pizza, chips and burgers. Sleep deprivation also changes the way you metabolize glucose, making your body store those calories as fat rather than burning them for energy.
So, not enough sleep equals possible weight gain. But how to get enough sleep? Click here for part two of this post: 5 tips to help fight insomnia.