There may not be an obvious link between sleep deprivation and your weight.
But more and more research is showing just how important sleep is for your mood, mental performance, overall health and wellness, and especially when it comes to maintaining a healthy weight.
Many studies show that people who have short sleep duration simply weigh more.
In fact, as the levels of chronic (long-term) sleep deprivation have increased over the past 50 years, so have the growing epidemics of being overweight or obese. An association (not causation) I know, but still important.
And many studies now agree that lack of sleep is an “independent” risk factor (i.e. a direct risk) for weight gain and obesity.
Especially for women.
Sleep and weight gain
One large analysis of 45 studies which included over 600,000 people says, “studies from around the world show a consistent increased risk of obesity among short sleepers in children and adults.” The increased risks were 89% for children and 55% for adults.
The overall data in that particular study suggests that a reduction in one hour of sleep per day would be associated with about 1.4 kg in additional weight.
Right now, 40% of American adults say that they get less than 7 hours of sleep per night and many less than 6. Evidence suggests that 7 hours is the minimum recommended nightly sleep, with 9 being the maximum.
Like stress, sleep and weight gain go hand-in-hand. So much so, assessing sleep is now routine for many in the know when it comes to weight management counselling.
Sleep deprivation and weight gain
You’re probably wondering how stress affects weight. Basically there are two main ways (with two factors each) that we think that lack of sleep contributes to weight gain and obesity.
First, it increases calorie intake in two ways.
FUN FACTS: Ghrelin is termed the ‘hunger hormone’ and tells your brain that you’re hungry. It is produced by your stomach where it promotes appetite, how food is turned into energy and storage of fat. Leptin is produced by your fat cells when you eat and signals your brain that you’re full.
Second, it decreases your ability to burn off calories in two ways.
- It can slow your metabolism; and
- It can cause fatigue and, therefore, reduced physical activity.
Let’s take a closer look at how your sleep and weight gain are related.
Lack of sleep increases time available to eat
Some researchers suggest that the longer you’re awake, the more opportunity you have to eat, or more specifically, to snack. In fact, some studies have shown that this tends to be the most difficult to get a handle on: nighttime snacks.
And guess what many sleep-deprived people tend to snack on at night? Carrots and hummus? Fruit? Nope.
You guessed it…high-fat, sometimes high-carb snacks that have less protein and fiber.
Which, of course, can lead to weight gain.
And, at least one study shows that eating at night increases the time it takes to fall asleep. Especially for women. So there is a bit of a “vicious cycle” in play here.
Lack of sleep messes with your hunger hormones
Many people who sleep less tend to eat more calories throughout the day. And not only due to increased time available for snacking, but also because of how lack of sleep can mess with the hormones that control both hunger and appetite.
How does this happen?
This is a “double-whammy” because some studies show that lack of sleep not only increases the stomach’s hunger hormone “ghrelin” (making you hungrier), but it also decreases the fat tissue’s fullness hormone “leptin” (making you feel less full). You stomach is pumping out more “eat more” ghrelin and your fat cells are dragging their feet and not sending the “eat less/stop eating” signal to your brain – bummer.
These changes can clearly lead to more eating, and eventually weight gain or even obesity.
It’s possible that this is a natural mechanism that our body uses to make sure we get enough food for longer waking times. But this doesn’t always serve us well, as it tends to make us “overshoot” our energy needs and take in a bit more than we actually need.
Lack of sleep may slow your metabolism
Research is just emerging on this topic, but it seems to show that sleep deprivation can lower your “energy expenditure” and body temperature.
A lack of sleep is perceived as stress and ongoing stress can impact your thyroid, impair it’s function and you can start to ‘run cold’. A lack of sleep also increases the release of the stress hormones adrenaline and cortisol. Higher background levels of cortisol increase fat accumulation around your middle.
This means that your body may naturally burn less fuel at rest during the days when you’re sleep deprived.
When you burn less, you store more fat.
Lack of sleep reduces exercise
You know how tired you feel after not getting enough sleep? It’s not fun. But it’s not just a lack of sleep that matters. Sleep quality is important too. This is why sleep apnea and weight gain are linked.
Sleep apnea is a sleep disorder which drives fatigue, and more fatigue can increase overweight and obesity. The rub is that being overweight then puts you at risk for worsening sleep apnea – and so on.
By increasing fatigue, sleep deprivation can reduce the motivation to exercise and be active. And when you’re burning less fuel at rest (slower metabolism), and less likely to exercise, you’re at risk of gaining weight.
Want to know the great news?
Sleep and weight loss is as important as what you eat and weight loss.
Lack of sleep is considered a “modifiable risk factor”. This means that, although it increases our risk for obesity, we have some power over it.
How well you sleep and how much sleep you get is something that you can improve by putting into place some tips and making them regular habits.
Tips for getting better sleep
1 – Make sleep a priority.
Let’s admit that, for a lot of us, the lack of sleep we’re getting is often because we simply give other activities priority. Making something a priority will help you achieve it.
2 – Be consistent with your sleeping times.
Your body loves routine, and having a consistent bedtime can actually train your brain, your body’s clock (circadian rhythm), and sleep hormones to follow suit.
3 – Eliminate stimulants after noon.
Ideally, you won’t expose your body to chemical stimulation for the whole afternoon and evening. This includes caffeine (coffee, black and green teas, chocolate) and nicotine (cigarettes).
4 – Get some exercise and sunshine during the day.
Of course exercise and sunshine have many health benefits. They also tell your brain that it’s daytime, so it can help to set your body’s clock.
TIP: Be sure to finish exercise at least three hours before bedtime, as it may stimulate some people and keep them awake.
5 – Stop eating and drinking a couple of hours before bed
By cutting out your bedtime snack you will eat fewer calories, and you may even have a better night’s sleep and wake up more alert. Also, by not drinking fluids a few hours before bed you’ll reduce the need to go the bathroom in the middle of the night.
6 – Lower your lights when the sun goes down
If your brain thinks it’s daytime it will not make the sleep hormone melatonin so it can stay awake. So, having bright white (or blue-ish) lights can trick your brain into thinking that it’s daytime.
So, you can dim your lights, buy amber/red light bulbs and/or blue-blocker glasses, turn off electronics (or at least use the f.lux or twilight apps), and if you do need to go to the bathroom during the night, don’t turn on the light.
7 – Create a relaxing pre-bed routine.
Choose something that you enjoy and will help to relax your body and mind and prepare it for a good night’s sleep, whether it be a warm bath, or reading a book.
And when you start feeling drowsy, just go to bed.
8 – Keep your bedroom comfortable
Having a room that is too hot, bright, or noisy can keep you from having a good night’s sleep. Ideally your room will be cool, completely dark, and either silent or with white noise.
9 – Get light as soon as you wake up
Turn on the lights or open the blinds as soon as you wake. This tells your brain to wake up and start the day.
Doug Cook RDN is a Toronto based integrative and functional nutritionist and dietitian with a focus on digestive, gut, and mental health. Follow me on Facebook, Instagram and Twitter.
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