Sleep is a bit like food for the brain. Feed it well, and it functions at its best. When it’s deprived, however, it can affect the body’s fat-burning power, which is why getting your beauty sleep is so important.
A study in the American Journal of Clinical Nutrition found that when people were starved of sleep, kilojoule intake from snacking increased, and they were more likely to choose high-carb snacks.
Another study published in the Journal of Clinical Sleep Medicine found that those who reported being short on sleep (less than seven hours) increased their risk of obesity, compared to those who reported sleeping around the recommended 7 to 8 hours a night. And in another study, researchers found that short sleepers had a higher BMI and waist circumference than long sleepers.
Why the link between lack of sleep and added weight? One reason may be because insufficient sleep has been shown to impact your hunger hormone, ghrelin, which stimulates appetite, and your fullness hormone, leptin, which signals that you’re full.
A few studies have examined these hormones and found lower leptin and higher ghrelin levels in short sleepers than normal sleepers – which means you’re more likely to grab an extra cup of coffee or a doughnut to compensate the lack of energy that comes from sleep deprivation.
Another contributing factor might be that lack of sleep leads to fatigue and results in less physical activity.
What about people who are trying to lose weight? Being short on sleep doesn’t appear to do any favours for those on a weight loss diet, either. One study showed that sleep restriction to 5.5 hours of sleep compared to 8.5 hours of sleep undermined the effectiveness of being on a weight loss diet. The combination of energy and sleep restriction in overweight adults resulted in less loss of fat and more loss of fat-free body mass, suggesting that sleep plays a role in the preservation of fat-free body mass during periods of reduced kilojoule intake.
In short, failure to consistently get a full night's sleep can lead to weight gain or compromise your body's ability to burn fat. But by getting around 7 to 9 hours of sleep every night, you can better control your appetite, feel more energised and reduce your risk of weight gain.
How to form good sleeping habits: