Do you have some days when you feel hungry all day, no matter what you eat? That might be because you didn't get enough sleep the night before.
What does the amount of sleep have to do with your weight? According to Harvard Medical School, lack of sleep is now being identified, along with lack of exercise and overeating, as the most common risk factors for obesity.
Not sleeping enough can hinder your weight loss efforts. Several studies have linked insufficient sleep to weight gain. People who normally sleep fewer than six hours per night were much more likely to be overweight. A lot of this has to do with how much of certain hormones your body makes, as I’ll explain below.
Inadequate sleep can undermine your weight loss efforts in these five ways:
- You’re hungrier. Not getting enough sleep or sleeping poorly affects the hormones that regulate your hunger levels. If you don't get enough sleep, your body makes more of the hormone ghrelin, which stimulates hunger, so you’re hungrier. The hormone leptin, which is the one that tells you you're full, decreases, so you eat more. The combination of too much ghrelin and cortisol, the stress hormone discussed in #3 below, shuts down the areas of your brain that make you feel satisfied after a meal, so you may feel hungry all the time. If you have those "hungry all day" days, notice whether they’re related to the amount of sleep you’ve been getting.
- Your metabolism suffers, and your body is more inclined to store fat. When you’re sleep deprived, your body suffers from “metabolic grogginess,” according to researchers at the University of Chicago. That means that your body can’t use the hormone insulin properly. When insulin functions well, your fat cells remove lipids and fatty acids from your blood and prevent them from being stored in your liver and on your body. But when you become more insulin resistant, those fat cells circulate in your blood and your body makes even more insulin. That’s not a good thing because to lose weight, your body must burn stored fat for energy, but when there is all that insulin in your blood, your body doesn’t use that fat.
- You crave junk food. Poor sleep leads to an increase in the hormone cortisol, which is your stress hormone. This affects both your appetite and your mood. To counter the extra cortisol, your body produces more serotonin, which is a feel-good hormone. This may be what makes you crave fat and carbs in the first place, because they lead to the release of serotonin. When you eat because you’re upset and feel better briefly afterwards, it is partly due to that serotonin spike.
- It’s harder to make healthy food choices. Sleep deprivation causes changes to the parts of your brain that govern eating. In one study, after a single night of sleep deprivation, participants wanted more unhealthy foods than when they got enough sleep. Also, sleep-deprived people were less able to make intelligent, reasoned decisions to overcome their urge to eat junk food or overeat. Sleep deprivation also makes you choose bigger portions. I’m sure you can figure out what happens when you eat more and bigger portions of unhealthy food!
- Your workouts are undermined. Not enough sleep interferes with your body’s ability to make muscle, which causes muscle loss and maybe even injuries. It also makes it harder for your muscles to recover after exercising by slowing down the production of growth hormone, which is produced during deep sleep. Plus, you may be too tired to get to the gym in the first place.
I know I’ve been talking about a lot of studies, but here’s one more, published in the American Journal of Epidemiology. This one concluded that women who are sleep deprived are a third more likely to gain 33 pounds over the next 16 years than women who get seven hours of sleep per night. Thirty-three more pounds! And that’s based on amount of sleep alone.
Some people don’t get enough sleep for reasons within their control, like going out and staying up too late when they have to get up early in the morning. Getting enough sleep is good self care, and if you’re in this category, I encourage you to plan so that you give your body the sleep it needs.
For many of us, though, insomnia is the problem. We want to sleep but have trouble doing that. There are many resources on the Internet on how to sleep better, like this one.
But here’s one tip: Don’t eat after dinner. There are two good reasons for this. First, you’ll sleep more soundly when your body isn’t busy digesting food. Second, eating will cause your body to produce more insulin, which will prevent you from burning fat during your natural fast between dinner and breakfast. So it goes without saying that midnight snacks are a really bad idea.
If you make getting enough sleep a health priority, you will likely find that managing your weight will become a little easier.