A large and ever-growing percentage of the population is overweight. Lack of exercise, labor-saving devices, easy access to high-calorie food, and mechanized transport are all contributing to this problem. Studies also suggest that lack of sleep is a factor too.
Life can be hectic, and that means a lot of us get less than the recommended eight hours of sleep per night. Unfortunately, long-term sleep deprivation significantly increases the likelihood of weight gain. Too little sleep leads to weight gain, and weight gain can cause a decrease in sleep quality; it’s a vicious cycle.
If you are struggling to lose weight or are experiencing weight gain, lack of sleep could be the reason. Here are six ways that sleep and weight gain are linked.
1. Lack of sleep increases hunger
Sleep helps to restore your energy levels. After a good night’s sleep, you should wake up feeling refreshed and ready to face the day. If you don’t get enough sleep, your body will demand energy from alternative sources, namely food.
Because your body wants rapidly-available sources of energy, you are more likely to crave and eat high carb and high sugar foods. These are the very foods most likely to lead to weight gain. If you often find yourself craving (and eating!) fast-acting carbs, sleep deprivation could be the cause.
2. Lack of sleep robs you of your willpower to eat healthily
You know that a banana is healthier than a muffin and that a homemade dinner of vegetables and fish is better for you than a takeout pizza. When your willpower levels are high, making healthy choices is easy. But, when you are tired, willpower takes a backseat, and you are more likely to make unhealthy choices. Sticking to a healthy eating diet is much harder when you are chronically tired, as you are much more likely to give in to hunger and cravings.
3. Lack of sleep can derail your workouts
In the same way that lack of sleep can rob you of the willpower needed to eat healthily, it can have a similarly detrimental effect on your workouts. Feeling tired is the perfect excuse to go home and eat instead of hitting the gym or going for a run. Combined with unhealthy food choices, this is a double whammy for weight gain.
In addition, sleep deprivation can make you want to avoid all forms of physical activity. When you are tired, you’ll be less inclined to walk short journeys, do household chores, or even stand up. Doing less general physical activity will lower your daily calorie expenditure, which can contribute to weight gain.
4. Lack of sleep may decrease your resting metabolism
Your resting metabolic rate is the number of calories your body uses at rest. It’s affected by several factors, including your gender, age, weight, height, and muscle mass. Studies have revealed that sleep deprivation can lower your resting metabolic rate by as much as 20%.
The occasional sleepless night shouldn’t present much of a problem, but regular sleep deprivation can have a lasting effect on your metabolism, making weight gain more likely and weight loss much more challenging than it needs to be.
5. Lack of sleep increases insulin resistance
When you eat carbohydrate, your body digests it and converts it into glucose. This triggers the release of the hormone insulin. Insulin transports glucose from your blood into your liver and muscle cells. At least, that’s what should happen.
If you are insulin resistant, instead of transporting glucose to your liver and muscles, the glucose is converted into triglycerides and then stored in your fat cells. This not only increases fat storage; it also makes it harder to burn fat and lose weight. It could also increase your risk of developing metabolic syndrome and type 2 diabetes.
Getting enough sleep has been shown to increase insulin sensitivity, making the above sequence of events much less likely.
6. Lack of sleep can lead to hormonal imbalances
Hormones are chemical messengers that tell the organs and systems of your body how to behave. Lack of sleep can have a profound effect on several hormones, all of which can lead to weight gain or may make losing weight harder than it needs to be. The main hormones affected by lack of sleep are:
- Ghrelin – this hormone is produced in your stomach. Lack of sleep increases ghrelin production. Elevated levels are responsible for increased hunger.
- Leptin – leptin is a satiety hormone. It tells your brain you are full, turning off the effect of ghrelin. Leptin levels tend to fall during periods of sleep deprivation.
Increased ghrelin and decreased leptin create a perfect storm for overeating and weight gain.
- Cortisol – cortisol is a stress hormone. Your body perceives a lack of sleep as a source of stress. High levels of cortisol promote fat storage, muscle loss, and a lower resting metabolic rate, all of which contribute to weight gain.
- Testosterone and growth hormone – these two hormones are anabolic, which means they are responsible for things like muscle growth and repair. These processes are highly energetic, i.e., they use a lot of energy. In addition, muscle mass requires a lot of calories to sustain it.
Levels of testosterone and growth hormone peak while you sleep. Inadequate supplies of these hormones could lead to muscle loss and a slower metabolism.
If you want to avoid weight gain or want to maximize fat loss, you must get enough sleep. Too little sleep affects how your body responds to food, increases your appetite, and erodes your willpower – both for exercise and for eating healthily. Worse still, the less you sleep, the more weight you’ll gain, and the harder you’ll find it to sleep.
However, if you can get a handle on sleep, clocking up the recommended eight or so hours per night, you will find it much easier to reach and maintain a healthy weight.
1. PubMed: Sleep and Obesity
2. PubMed: Resting metabolic rate varies by race and by sleep duration