6 Ways Sleep May Help You Lose Weight
If you’re trying to lose weight, the amount of sleep you get may be just as important as your diet and exercise.
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).
Interestingly, mounting evidence shows that sleep may be the missing factor for many people who are having difficulty losing weight.
Here are 6 reasons why getting enough sleep may help you lose weight.
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).
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
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).
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
Getting enough sleep may help prevent increases in calorie intake and appetite that can happen when you’re sleep deprived.
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
Getting a full night’s sleep may help you make healthier food choices.
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
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).
Interestingly, late-night eating is associated with greater weight gain, a higher BMI, and decreased fat oxidation — making weight loss more difficult (25Trusted Source, 26Trusted Source, 27Trusted Source, 28Trusted Source).
What’s more, eating too close to bedtime, especially large meals, may decrease the quality of your sleep and make your sleep deprivation even worse. In particular, those with acid reflux, indigestion, or sleep disorders may want to limit food intake before bed (29Trusted Source, 30Trusted Source, 31Trusted Source).
Ideally, try to limit your food intake 2–3 hours before bed. That said, if you’re hungry, consider having a small, protein-rich snack, such as Greek yogurt or cottage cheese.
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:
- muscle mass
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).
This study suggests that sleep deprivation may reduce RMR, but that you may be able to bring your RMR back up by getting proper sleep for at least one night (34Trusted Source).
On the contrary, other studies have found no changes in metabolism with sleep loss and suggest energy expenditure may actually increase with short sleep because you’re awake for longer (35Trusted Source, 36Trusted Source).
Therefore, more research is needed to determine whether and how sleep loss affects metabolism.
Lack of sleep may also suppress fat oxidation, which is the breakdown of fat cells into energy.
One study found that sleep deprivation resulted in significantly lower basal fat oxidation in people of different ages, sexes, and body composition. However, RMR was not affected (37Trusted Source).
It also seems that poor quality sleep may decrease muscle synthesis, which may lower RMR.
One small study showed muscle synthesis decreased significantly by 18% and plasma testosterone by 24% after one night of poor sleep. Additionally, cortisol significantly increased by 21%. Collectively, these conditions contribute to the breakdown of muscle (38Trusted Source).
However, this study was small and only 1 day long, which are major limitations. Furthermore, other studies suggest that sleep deprivation doesn’t affect muscle repair and growth. Thus, longer and larger studies are needed
Sleep and physical activity have a close two-way relationship. A lack of sleep decreases physical activity, and lack of physical activity may lead to worsened sleep (41Trusted Source, 42Trusted Source).
Numerous studies have shown that regular exercise can decrease the time it takes you to fall asleep and increase the overall quality of sleep across all age groups (42Trusted Source, 43Trusted Source, 44Trusted Source, 45Trusted Source).
Furthermore, a lack of sleep can cause daytime fatigue, making you less motivated to exercise and more likely to be sedentary.
In turn, you may expend fewer calories in a day when sleep deprived than you would after a proper night’s rest. This can make achieving a calorie deficit for weight loss more difficult.
- reaction time
- fine motor skills
- muscular power
- problem solving skills
It may also increase your risk of injury and delay recovery.
Ultimately, getting enough sleep is key to staying active.