September 4, 2017

We all know that regular exercise and a healthy diet are key elements for weight loss, however making sure that you get healthy sleep is often overlooked. Research has shown that sleep plays an important role in weight management as people who sleep enough have lower BMI than people who don’t. The data also suggests that sleep deprivation can cause weight gain.

Could lack of sleep be causing you to gain weight?

Think about it: If you’re feeling sleepy at work, you may be tempted to reach for a cup of coffee (or several cups) and a snack for a quick shot of energy. Later you skip the gym and pick up takeaway – no time to cook. When you finally find yourself back in your bed, you’re too wound up to sleep.

It’s a vicious cycle, and eventually this sleep deprivation can sabotage your waistline and your health.

If you’re what researchers call a short sleeper (5.5 to 6 hours per night), you’ll have trouble losing weight. In a 7-year study of 7,022 middle-aged people, Finnish researchers found that women who reported sleep problems were more likely to experience a major weight gain (defined as 11 pounds or more).

Understanding the sleep-diet connection

Maybe you’ve heard about the ‘Sleep diet’, which suggests you can lose weight while you sleep. And it’s true, sort of. It’s not that sleep makes you lose weight, but if you’re sleep-deprived your metabolism won’t function properly.

In research presented at the American Heart Association’s 2011 Scientific Sessions, it was shown that women who got only 4 hours of sleep at night ate 329 additional calories the next day than they did after they slept nine hours. (Men ate 263 calories more.) In another study, published in the American Journal of Clinical Nutrition, volunteers spent 14 days at a sleep centre on two occasions. During one period, they slept 5.5 hours a night, and during the other, they slept 8.5 hours. When the subjects were sleep-deprived, they increased their night-time snacking and were more likely to choose high-carbohydrate snacks.

How hormones affect your sleep

On average, we need about 7.5 hours of quality sleep per night. Exactly how lack of sleep affects our ability to lose weight has a lot to do with our hormones. Substantial medical evidence suggests some fascinating links between sleep and weight. Researchers say that the quantity and quality of your sleep may silently orchestrate a symphony of hormonal activity tied to your appetite.

Leptin and Ghrelin

Research on the hormones leptin and ghrelin are what really turned attention to how hormones affect appetite. Studies show that production of both hormones may be influenced by how much or how little we sleep. Ghrelin, produced in the gastrointestinal tract, is the hunger hormone that tells you when to eat. It also promotes the retention of body fat. When you’re sleep-deprived, you have more ghrelin. Leptin, produced in the fat cells, is the satiety hormone that tells your brain that you’ve eaten enough and to stop eating; when you are sleep deprived, you have less leptin. More ghrelin plus less leptin equals over-eating which leads to weight gain.

Growth Hormone

During sleep, your pituitary gland secretes more growth hormones than during your waking hours. Growth hormones stimulate cell regeneration, reproduction and growth. These hormones are also known to aid you in building muscles. This is why higher levels of growth hormones mean a heightened metabolism. With a higher metabolism, you burn energy much faster which leads to easier weight loss.


Getting eight hours of sleep at night helps you lower the cortisol levels in your blood, while lack of sleep raises your cortisol levels. Higher levels of cortisol lead to a lower metabolism because cortisol stimulates the breakdown of protein down into glucose.

On top of this, cortisol interferes with your body’s ability to build muscle mass, so increasing your metabolic rate is difficult. If you are trying to lose weight, you want to make sure that you have low cortisol levels in your blood. Getting enough sleep helps you do just that.


Insulin is produced in the pancreas and transports glucose in the blood to storage sites in the liver, muscles and fat cells, helping to lower blood glucose levels and increase the size of fat cells. The higher the blood glucose, the higher the insulin, and the higher the insulin the more storage occurs. This is the way eating a high-carbohydrate diet leads to weight gain.

A small study found that lack of sleep alters the biology of fat cells. The healthy volunteers moved from 8.5 hours of sleep to just 4.5 hours and the changes to their cells were tracked. After four nights of less sleep, their fat cells were less sensitive to insulin which can lead to Insulin Resistance and Type 2 Diabetes, as well as obesity.

Rest and Recovery

Exercising regularly is a great way to improve your fitness. When you exercise, you tire your body and inflict small injuries to your muscles. Your body recuperates during sleep, so if you don’t sleep enough you stay fatigued and essential repair is not as reliable. Sleeping enough will allow your body to rest, recover and grow stronger, boosting your metabolism and making weight loss easier.

So, what can you do about sleep deprivation?

  • First, look at not just the quantity but also the quality of your sleep. Sleep changes according to the conditions in your life. A new mum, for example, might be lucky to sleep for four hours at a time. Someone with pain might sleep for eight hours but be continuously disturbed as the pain wakes them.
  • Avoid any caffeine in the afternoon because it will keep you in the lighter stages of sleep – which are associated with poor sleep – at night.
  • Watch what you eat and drink before bedtime. Junk foods and alcohol both disturb the quality of sleep in most people, so these are best avoided to improve sleep and, of course, to improve weight loss results.
  • Exercise also helps improve sleep quality. How soon before bed should you exercise? It depends – everyone is different. It’s more important that you exercise than it is when you exercise. Most people find that it’s best to avoid exercise right before going to bed, although for others this helps them to sleep better.

Sleep: You can’t lose

Most experts agree that if weight loss is your aim, logging in a few extra hours of sleep a week is not a bad idea, particularly if you get six hours of sleep or less a night. You may just discover that you aren’t as hungry, or that you have reduced your craving for sugary, calorie-dense foods.

Sleep is a crucial factor in losing weight. Sleep suppresses your appetite and raises your metabolism, while allowing your body to rest and recover. So aside from leading an active lifestyle and maintaining a healthy diet, you should also make sure that you get your full eight hours of shuteye every night.