The amount of sleep you get may be just as important for weight loss as your diet and exercise. Evidence shows that sleep may be the missing factor for many people trying to lose weight.
Unfortunately, many people aren’t getting enough sleep.
In fact, about 35% of US adults are sleeping fewer than 7 hours most nights, according to the Centers for Disease Control and Prevention (CDC). Getting fewer than 7 hours of sleep at night is considered short sleep (1Trusted Source).
Here are 6 reasons why getting enough sleep may help you lose weight.
1. May help you avoid weight gain associated with short sleep
Short sleep — usually defined as fewer than 6–7 hours — has been repeatedly linked to a higher body mass index (BMI) and weight gain.
One analysis of 20 studies including 300,000 people found a 41% increased obesity risk among adults who slept fewer than 7 hours per night. In contrast, sleep was not a factor in the development of obesity in adults who slept longer (7–9 hours per night) (2Trusted Source).
Another study found short sleep duration to be significantly associated with greater waist circumference, which is an indicator of the accumulation of belly fat (3Trusted Source).
Other studies have found similar results (Trusted Source4Trusted Source, 5Trusted Source, 6Trusted Source).
Studies have also found similar associations in children and adolescents.
In a recent review of 33 observational and intervention studies, short sleep duration was associated with an increased risk of obesity. Interestingly, for every additional hour of sleep, BMI scores decreased (7Trusted Source).
Another review of many observational studies found short sleep duration was associated with a significantly higher risk of obesity in these different age groups (8Trusted Source):
Infancy: 40% increased risk
Early childhood: 57% increased risk
Middle childhood: 123% increased risk
Adolescence: 30% increased risk
One major review found that short sleep duration increased the likelihood of obesity in children by 30–45% (9Trusted Source).
Though lack of sleep is only one factor in the development of obesity, research suggests it negatively affects hunger levels, influencing a person to consume more calories from high fat and high sugar foods.
It may do this by affecting hunger hormone levels, increasing ghrelin, which makes you feel hungry, and decreasing leptin, which makes you feel full (4Trusted Source, 10Trusted Source, 11Trusted Source).
Ghrelin is a hormone released in the stomach that signals hunger in the brain. Levels are high before you eat, which is when the stomach is empty, and low after you eat. Leptin is a hormone released from fat cells. It suppresses hunger and signals fullness in the brain (12Trusted Source, 13Trusted Source).
Poor sleep may also negatively affect the sympathetic nervous system, resulting in increased levels of cortisol — a hormone related to stress (10Trusted Source).
It may also suppress various hormones, such as levels of insulin-like growth factor 1 (IGF-1). IGF-1 is linked to greater fat storage (10Trusted Source, 11Trusted Source, 14Trusted Source).
Additionally, many sleep disorders, such as sleep apnea, may get worse with weight gain. Unfortunately, this can lead to a cycle of poor sleep leading to weight gain and weight gain leading to poor sleep (15Trusted Source).
2. May help moderate your appetite
Getting enough sleep may help prevent increases in calorie intake and appetite that can happen when you’re sleep deprived.
Many studies have found that people who are sleep deprived report having an increased appetite and a higher daily calorie intake (16Trusted Source, 17Trusted Source).
In fact, one review of studies found that those who experienced sleep deprivation consumed an additional 385 calories per day, with a greater than usual proportion of calories coming from fat (18Trusted Source).
Another study showed that sleep deprivation led to significant increases in hunger, food cravings, portion sizes, and chocolate and fat intakes (19Trusted Source).
The increase in food intake is likely caused partly by the effect of sleep on the hunger hormones ghrelin and leptin.
When you do not get adequate sleep, the body makes more ghrelin and less leptin, leaving you hungry and increasing your appetite (12Trusted Source, 13Trusted Source).
3. May help you make better food choices
Getting a full night’s sleep may help you make healthier food choices.
Lack of sleep alters the way your brain works and can affect decision making. This may make it harder to make healthy food choices and resist tempting foods (20, 21Trusted Source).
In addition, it appears that the reward centers of the brain are more stimulated by food when you are sleep deprived (20).
For example, one study found that sleep deprived participants had greater reward-related brain responses after viewing images of high calorie foods. Interestingly, they were also more likely to pay more for food than those who had adequate sleep (22Trusted Source).
Therefore, after a night of poor sleep, not only is that bowl of ice cream more rewarding, but you’ll likely have a harder time practicing self-control.
Another study showed that sleep deprivation led to increased smell sensitivity to high calorie foods and greater consumption (23Trusted Source).
Furthermore, lack of sleep may lead to poorer food choices, such as a higher intake of foods high in calories, sugar, and fat, to compensate for feeling a lack of energy (13Trusted Source).
4. Sleeping early can prevent late-night snacking
Going to sleep earlier may help you avoid the late-night snacking that often comes with staying up past your bedtime.
Pushing your bedtime later means you’re staying up longer, which creates a larger window of time for eating, especially if it has been many hours since dinner (24Trusted Source).
For example, if you ate dinner at 6:00 p.m. and you stay up until 1:00 a.m. every night, you’re likely going to be hungry at some point between dinner and bedtime.
If you’re already experiencing sleep deprivation, you may be more likely to opt for less nutritious options. That’s because sleep deprivation can increase your appetite and craving for high calorie, high fat foods (13Trusted Source).
5. Potential benefits for your metabolism
Getting enough sleep may help you avoid decreases in metabolism that can happen when you haven’t gotten enough sleep.
Your resting metabolic rate (RMR) is the number of calories your body burns when at rest. It’s affected by many factors, such as:
age
weight
height
sex
muscle mass
Interestingly, sleep duration may also affect your RMR (32Trusted Source, 33Trusted Source).
One study including 47 participants looked at how sleep restriction affected RMR. The experimental group slept normally for 2 nights (baseline) followed by 5 days of sleep restriction with 4 hours per night (34Trusted Source).
Finally, they had one night of “catch-up” sleep, during which they spent 12 hours in bed (34Trusted Source).
During the 5 days of sleep restriction, participants’ RMR significantly decreased compared with the baseline. However, their RMR returned to normal after the “catch up” sleep. The control group had no significant changes to their RMR (34Trusted Source).
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