How Sleep Affects Weight Loss

Do you struggle with getting enough sleep? Do you also happen to struggle with losing weight? Well, these two things share a stronger association than you might think, and research continues to suggest that improving one will have a mutually beneficial effect on the other. That’s right, a growing body of evidence is destabilizing our notions of eating less and exercising more as the ultimate key to attaining our desired weight loss, and enlightening us as to what might be the most relaxing weight loss regime we’ve ever embarked on – simply, getting ample sleep.

Astonishingly, 40% of adults report either short term or chronic insomnia, a fact that may also help explain the rise in obesity across the country. We’ll go through the evidence of some of the subtle and more obvious ways that sleep and weight are interconnected, and hopefully convince you that healthy sleeping habits are key to maintaining a healthy weight and lifestyle.

Sleep and Hunger Hormones

If you commit yourself to making healthy food choices during the day and often get frustrated when, lo and behold, you give in to temptation once again — take some comfort in knowing that your willpower is not the only factor at play when food cravings hit. Research shows that hunger and food cravings are largely controlled through two hormones: leptin and ghrelin.

Leptin is released by your body’s fat cells and is deeply involved in appetite regulation, metabolism, and calorie burning. When your body wants to tell you that it’s time to stop eating, it releases leptin to suppress appetite and stimulate energy expenditure (calorie burning). While you sleep, leptin levels increase, and this tells your body that you have lots of stored energy and that there’s no need to trigger the feeling of hunger. However, when you begin to lose sleep or you’re sleep deprived, you fail to build up enough leptin in the body, which ultimately signals your brain that your body is lacking energy and that it’s time to start eating.

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Sleep also boosts the production of ghrelin, what can be considered the opposing hormone to leptin. When your body is in motion or getting low on energy stores, ghrelin acts to tell your brain to start eating, stop burning calories, and reserve energy as fat. While you sleep, your levels of ghrelin drop, largely because sleep requires far less energy than being awake. The result of sleep deprivation leaves you with an excess build-up of ghrelin in your system, telling your body to eat more and to stop burning calories.

The effects of these two hormones are becoming increasingly clear as research delves into the implications of sleep deprivation. In one study from Stanford University, researchers found that shorter sleep times were associated with increased circulating ghrelin and decreased leptin, and that in those sleeping less than 8 hours a night, increased BMI was proportional to decreased sleep. What’s more, researchers have also found evidence of the opposite effect—where taking leptin and ghrelin as supplements can actually alter sleep patterns, working to decrease deep sleep in both mice and human subjects.

And it doesn’t stop there.

Lack of sleep has also been shown to increase levels of cortisol, the stress hormone, which is associated with fat gain. Have you ever binge eaten while stressed? The same idea applies when your body and brain are stressed from lack of sleep. The combination of cortisol and ghrelin shut down the area of your brain that would normally make you feel satisfied after a meal, so that you feel hungry – and eat – constantly under the pressure of sleep deprivation. Cortisol also makes you crave high-calorie foods, making it even likelier that you’ll indulge in the wrong types of foods when you’re lacking sleep and the munchies hit.

Sleep and Fat Storage

If you’re prioritizing exercise over sleep when you’re faced with a busy schedule, you might want to think again. A study from Cedars-Sinai Medical Centre in Los Angeles have shown that a single night of sleep deprivation can cause as much insulin resistance as six months on a high-fat diet. In the study researchers deprived eight dogs of a night’s sleep, then tested their insulin sensitivity using intravenous glucose tolerance tests. Results showed that one night of sleep deprivation decreased insulin sensitivity by 33%, while dogs put on a six month, high-fat diet saw insulin sensitivity decrease by 21%.

But what does insulin have to do with anything? Insulin assists the entry of glucose from your food into your body’s cells. When your system gets loaded with glucose, it causes a shift in your metabolism and slows down fat breakdown, as well as starts the synthesis of new fat. Decreased insulin sensitivity, as seen in the sleep-deprived dogs, means that glucose is no longer clearing into cells as efficiently, and fat synthesis is on the rise. Decreased insulin sensitivity, otherwise known as insulin resistance, is a major cause of obesity.

Sleep and Exercise

At this point you might be thinking that: yes, it might be true that sometimes you’re skimping on your full eight hours, but shouldn’t your hard work in the gym counteract some of the effects of your sleep deprivation? Unfortunately, sleep deprivation has a serious impact on your workouts and on your ability to burn fat. First, we all know that building lean muscle is key to sustaining a healthy body weight – and sleep deprivation may be preventing you from doing just that. A study published from the University of Chicago put ten overweight males and females in a sleep research centre for two separate periods and for two weeks each. Participants all followed an identical low calorie diet. However, one group slept 8.5 hours per night, while the second group slept 5.5 hours each night. While both groups lost around 7 pounds each, the dieters with less sleep lost mainly muscle rather than fat.

Similarly, a lack of sleep makes it harder for your body to recover from a hard workout by slowing down the production of growth hormones – our natural source of anti-aging and fat burning, which also helps recovery after a hard workout. Human growth hormone (often abbreviated HGH) promotes a healthy metabolism, and is released both during exercise and during sleep. However, some researchers estimate that as much as 75% of human growth hormone is released during sleep. Cortisol, the stress hormone we mentioned earlier that is also released when you’re lacking sleep, also acts to slow the production of growth hormone.

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Finally, one of the more obvious connections between lack of sleep and fat loss is your ability to actually keep up with your exercise regime. If you’re not getting enough sleep, everything during the day feels harder and more laborious, not least the high intensity interval training workout you had planned after your long day at work.

What You Can Do to Counteract the Sleep Deprivation – Weight Gain Cycle

Sleep deprivation is not only detrimental to your summer bikini goals; it is also connected with a host of other ill effects including obesity, diabetes, high blood pressure, and heart disease. While everyone is different, the National Sleep Foundation recommends that you get between 7 and 9 hours of sleep per night.

The most important thing to do to combat sleep deprivation is to make sleep a top priority in your life. In a study published by the American Journal of Epidemiology, women who were sleep deprived were 30% more likely to gain 33 pounds over the next 16 years than those who got at least 7 hours of sleep every night.

While there are some days in life that stress and lack of sleep are unavoidable, you should try to stick to a routine that allows you to wind down at the end of your day and allow your brain and body to get a good night’s rest. If you have trouble falling asleep due to reasons beyond time constraints, try these tips to fall asleep faster:

  • Don’t drink caffeine or alcohol anywhere near your bedtime. Although for different reasons, both of these substances will make it harder to sleep and reduce the quality of your sleep.
  • Exercise earlier in the day. As mentioned above, getting enough sleep is key to an efficient and beneficial workout, so don’t let your exercise regime keep you from sleep. Try to workout at least 4-6 hours before going to bed – this will give your body time to wind down from your workout and feel ready for some well-earned rest.
  • If you’re feeling anxious or stressed, there are a number of techniques that might help you fall asleep faster. Try finding some guided meditations online, take a shower or bath to relax and cool off after a long day at work, listen to some relaxing music, try lavender oil or aromatherapy, or try writing or reading away your worries
  • Finally, avoid napping during the day. Napping more than 30 minutes can upset your sleep cycle and mess with your metabolism. Work through your drowsiness if you can, and if you absolutely must nap, try to limit it to 30 minutes.

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