Editor’s note: This article has been reprinted. First published November 17, 2016.
Have you ever woken up after a sleepless night and felt like you wanted to eat everything in sight? It’s not your imagination. The quality of your sleep has been proven time and time again to play a role in what you eat the next day.
This association is so strong that you absolutely need to pay attention to your sleep, or lack thereof, if you’re trying to lose a few pounds. Even if you exercise regularly and diligently follow a healthy diet (both important in their own right), sleep problems can derail your weight loss efforts. Here’s how:
One night of limited sleep can cause you to consume nearly 400 extra calories
When researchers reviewed data from 11 sleep studies involving more than 170 people, the results were clear. Limited sleep (usually about four hours a day) causes people to eat more than they would after a full night’s rest.1
On average, participants consumed an additional 385 calories after sleeping poorly, including more fat and less protein. There was no effect on participants’ activity levels. This means that there is a “net positive energy balance” that can lead to weight gain over time.
There are many theories as to why less sleep causes you to eat more, including increasing ghrelin, the “hunger hormone,” and decreasing leptin, a hormone associated with satiety. However, the authors of the featured study suggested that sleep deprivation also increases the desire to seek food as a reward.2
In fact, a 2012 study found that limited sleep (4 hours a day) increased activation in brain regions sensitive to food stimuli. There was also increased brain activity in areas associated with reward, which helps explain why not getting enough sleep triggers overeating through the brain.3
Lack of Sleep Makes You Snack
In most cases, willpower alone isn’t enough to overcome the not-so-subtle effects sleep deprivation has on your appetite. That’s because sleep restriction is associated with activation of the same endocannabinoid system that is activated by marijuana.
This system is involved in regulating appetite and food intake. One study compared the effects of normal sleep (8.5 hours) and restricted sleep (4.5 hours) over four days in 14 young adults.4
Levels of the endocannabinoid 2-arachidonoylglycerol (2-AG), the chemical that makes food enjoyable, increased when participants were sleep-deprived.5 On a typical day, 2-AG levels tend to drop overnight and then slowly increase until they peak in the afternoon. However, in sleep-deprived people, levels remained high until late in the evening.
Accordingly, participants reported that getting less sleep increased their hunger and appetite and made them less able to suppress their junk food intake. They ate snacks that were nearly twice as high in carbohydrates, fat, and protein as they did when they were well-rested.
Past research has similarly shown that people who are chronically sleep-deprived and go to bed late are more susceptible to weight gain because they eat more during the day and later at night.6
Poor sleep causes insulin resistance
Another revealing study found that one night of sleep deprivation resulted in impaired insulin sensitivity similar to that caused by eating the wrong diet for six months.7 Dr. Josiane Broussard, project scientist at the Diabetes and Obesity Institute at Cedars-Sinai Medical Center in Los Angeles, California, said in a press release:8
“This study demonstrates the importance of adequate sleep in maintaining blood sugar levels and reducing the risk of metabolic diseases such as obesity and diabetes.”
By the way, insulin resistance not only causes weight gain, but also chronic diseases such as cancer. This explains why men who sleep poorly have been found to be twice as likely to develop prostate cancer compared to men who sleep well.9
Insufficient sleep is also a contributing factor to breast cancer recurrence and more aggressive forms of breast cancer in postmenopausal women.10 Getting less than six hours of sleep per night is also associated with a risk factor for colon adenomas, which can develop into cancer if left untreated.
People who sleep less than 6 hours a night have a 50% higher risk compared to people who sleep more than 7 hours.11 Another reason why sleep deprivation causes cancer has to do with melatonin, the production of which is disrupted by sleep deprivation.
This is very problematic because melatonin not only inhibits the proliferation of a wide range of cancer cell types, but also causes cancer cell death (suicide).
Even children gain weight if they lack sleep.
With overweight and obesity rates soaring in children, addressing sleep issues is critical. Even relatively small changes in sleep habits, such as increasing or decreasing the amount of sleep you get by 1.5 hours per night, can have an impact.
For example, in one study, children ages 8 to 11 had their bed time increased or decreased by 1.5 hours per night for one week, then reversed the schedule for the next week. When children slept more, significant benefits were reported, including consuming an average of 134 fewer calories per day and losing half a pound of body weight.12
In 2011, researchers similarly found that getting an extra hour of sleep a night between the ages of 3 and 5 was associated with a 61 percent reduction in the risk of being overweight or obese at age 7.13 And specifically, the weight gain was caused by increased body fat.
A separate 2013 study also found that sleeping just one more hour a night lowered the risk of being overweight by 28 percent and the risk of obesity by 30 percent.14
What to Do If You Can’t Get Enough Sleep — Optimize Light Exposure
If you’re having trouble sleeping, take a quick inventory of your light exposure. Do you spend most of your day indoors exposed to artificial light, and do you spend most of your night in front of artificial light such as a TV, computer, or cell phone?
Adjusting this exposure so that you are exposed to bright natural light in the morning and blue light at night is very important for healthy sleep. In the morning, bright, blue-rich sunlight signals your body that it’s time to wake up. When the sun sets at night, the darkness should signal to your body that it is time to sleep.
Ideally, you should get at least 10 to 15 minutes of natural light first thing in the morning to help your circadian system reset itself. This will send a strong message to your internal clock that the day has arrived, making it less likely to be confused by weak light signals later.
Then take another “dose” of sunlight for at least 30 minutes around solar noon. An hour or more would be better. If your schedule requires you to wake up and get to work before the sun rises, aim to get at least 30 minutes of bright sunlight during the day.
In the evening when the sun begins to set, wear amber-colored glasses that block blue light. Also, reduce your exposure to light, which suppresses melatonin production, by dimming the lights and turning off electronic devices.
If you need lighting after the sun goes down, switch to low-wattage bulbs with yellow, orange, or red lights. A salt lamp illuminated by a 5-watt bulb is an ideal solution as it does not interfere with melatonin production.
If you plan to use your computer or smartphone in the evening, install blue light blocking software such as f.lux. f.lux automatically changes the color temperature of your screen as the day progresses to bring out blue wavelengths. late. But as mentioned earlier, the easiest solution is to wear blue light blocking glasses to avoid exposure to blue light after sunset.
Precautions before exposure to sunlight
Sun exposure is the best way to optimize your circadian rhythm and vitamin D levels. However, there are some precautions to keep in mind. This is especially true if you eat a diet high in linoleic acid (LA), an omega-6 fat that is one of the deadliest toxins in the Western diet.
The problem with LA is that when they become lodged in the skin and exposed to sunlight, they cause inflammation and DNA damage. To prevent this from happening, it is recommended that you avoid peak midday sun exposure until you have eliminated all seed oils and processed foods from your diet for 4 to 6 months.
Over time, your body will rid itself of LA and allow you to be exposed to sunlight again at noon. However, in the meantime, you should avoid intense midday sunlight and only expose yourself to sunlight in the early morning and late afternoon (for a few minutes at a time) when UV rays are least damaging.
How many hours of sleep is enough?
If you jump out of bed in the morning feeling well-rested and alert, you’ll know you’ve gotten enough sleep. If you feel sluggish and suffer from daytime fatigue, you probably can use more. The exact amount of sleep an individual needs depends on factors such as age and health status.
In February 2016, the Centers for Disease Control and Prevention (CDC) reported that one in three American adults does not get enough sleep.15 In this case, “adequate” sleep was defined as seven or more hours a night, but many adults need closer to eight hours a night (so sleep deprivation affects more than one in three adults).
If you’re not sure how long you’re sleeping each night, a wearable fitness tracker can help you monitor how much time you’re actually asleep (as opposed to time spent lying awake) so you can adjust your schedule accordingly. If you need more sleep and have a set wake time, you should go to bed earlier.
In addition to controlling light exposure, proper “sleep hygiene” is also important. To achieve this and more restful and restorative sleep, we encourage you to read our full 33 Healthy Sleep Guidelines for all the details.
