When it comes to weight loss, it’s usually diet and exercise that we think of first to achieve a healthy weight. But what if the solution was as simple as getting an extra hour of sleep a night? Did you know that in 1910 people slept on average nine hours a night? Fast forward to today and a third of all adults’ report getting less than six hours of sleep a night! What many people may not realize is that sleep, or the lack of, can influence the likelihood we will gain weight, particularly weight around our middle.
A recent study of sleep deprived adults has provided the first real evidence linking lack of sleep to abdominal obesity and harmful visceral, or ‘belly fat’. This is the unhealthy fat that accumulates around your organs. In the study, healthy individuals were randomly assigned to the control group (nine hours in bed) or to the restricted group (four hours in bed). Both groups ate the same number of calories and performed the same level of exercise over the fortnight.
At the end of the two weeks, those participants who slept fewer hours had gained weight – around half a kilo. Now, this might not sound like a lot, but an extra pound of fat in the belly area is significant. Remember, these weren’t sick people, but young healthy people who were sending fat to the wrong place. The trouble with belly fat is that it’s not limited to the extra layer of padding located just below the skin (subcutaneous fat). It also includes visceral fat — which lies deep inside your abdomen, surrounding your internal organs including your liver and your intestines. This is of particular concern because it is a key player in a variety of health problems including cardiovascular disease and type 2 diabetes.
Why does sleep deprivation cause us to gain weight? There are a few reasons…
- You eat more. According to research, a bad night’s sleep can mean we eat an extra 200-450 calories the following day. When we’re sleep deprived, we have less willpower and poor decision making skills, meaning we’re more likely to choose foods that will stall weight loss. Plus, when you’re awake longer, you have more time to eat! There is certainly something to be said for shutting down your kitchen at a designated time and making a conscious effort to spend that time winding down and easing yourself into sleep.
- You don’t feel full. When we are tired the hormone leptin is affected, meaning we are less likely to feel full and satiated from our meals. Leptin is a hormone that decreases appetite, so when leptin levels are high, we usually feel fuller. On the other hand, ghrelin is a hormone that can stimulate appetite, and is often referred to as the “hunger hormone” because it’s thought to be responsible for the feeling of hunger. Several studies show that less sleep increases levels of ghrelin and decreases leptin, therefore increasing hunger.
- You crave sugar. Along with changes in appetite hormones, reduced sleep has also been shown to impact on what we choose to eat and the way the brain perceives food. When we’re tired, healthy food seems less appealing and more of a hassle to prepare. We’re much more likely to turn to fast food and quick energy fixes. Cravings can increase by a whopping 30% after a poor night’s sleep!
- Your stress hormone, cortisol rises. A single night of sleep deprivation increases cortisol levels by more than 100%. By the next evening, cortisol can still be up to 45% Cortisol drives up blood sugar which can result in both high insulin and insulin resistance.
- Your cells are less sensitive to insulin. Even a single night of little sleep can impair our sensitivity to insulin by up to 40%! When food is eaten, our bodies release insulin, a hormone that helps to process the glucose in our blood. However, sleep loss can impair our bodies’ response to insulin, reducing its ability to uptake glucose. Given that sleep deprived people already tend to choose foods high in sugar due to an increased appetite, this effect on insulin sensitivity means more of it is likely to be stored as fat.
- You slow down. Exercise and movement go out the window when we are tired. We naturally slow down to conserve energy. Fatigue is one of the biggest appetite saboteurs.
Plenty of movement, good nutrition and reducing stress are all important factors in reducing belly fat and improving general health, but you can’t ignore the role of sleep. It’s clear that sleep is important for losing weight, especially around our waist, and a lack of it will undermine any effort to reach a healthy weight.
As naturopaths we use specific nutritional supplements like magnesium, zinc and chromium to address insulin sensitivity, specific herbal medicines to facilitate cortisol management, as well as particular herbal and nutritional medicines to help overcome poor sleep habits. If you have been struggling with weight gain and would like some support to achieve your health and body goals, our naturopaths would love to be part of your team!