Sleep And Weight Loss
Can Getting More Sleep Help You Lose Weight?October 26th, 2012
By Holly Klamer, MS, RD
Edited by Brian Rigby, Clinical Nutrition Writer
You can add the amount of sleep you get per night to the list of things that may contribute to obesity risk, especially for children, according to a 2012 review article in Obesity. Of course eating right and exercising are the foundations of weight loss, but some research suggests sleep may be an important factor as well in weight gain or loss.
An interesting observation is that alongside the obesity epidemic that has occurred over the past 20+ years, sleep deprivation has increased as well. Researchers are still deciphering the relationship between the two, but it seems so far that there is an association between sleep and weight loss.
Sleep And Hormones
Chronic sleep deprivation can lead to a constant feeling of fatigue, decreased desire for physical activity, and can affect hormone levels in the body. According to a 2008 study in Journal of Sleep Research, just a one night lapse of sleep (4.5 hours one night and no sleep another night) can alter leptin and ghrelin levels in healthy adult men. In total sleep deprivation, the subjects self-reported significantly higher levels of hunger compared to seven hours of sleep and 4.5 hours of sleep.
Leptin and ghrelin are hormones that play a role in energy balance. Ghrelin is a fast acting hormone that signals the brain it is time to eat, and leptin is a longer lasting hormone released from fat cells. As body weight goes down, leptin levels decrease as well, signaling that there is a decreased amount of fat in the body. Conversely, leptin levels go up when weight increases, signaling to the brain that there is enough energy in storage and food intake can be decreased. Sleep deprivation alters the balance of these hormones and increases the signal in the brain to eat.
Some studies have shown a higher food intake with decreased sleep. If ghrelin and leptin levels are affected by lack of sleep and enhance hunger signals, this would promote eating more calories through the day, which may be one reason explaining increased weight gain from lack of sleep. However, not all studies have shown an increased calorie intake in deprived sleepers.
Television watching was not significantly related to weight gain in sleep deprivation in most studies. One study did find that core temperature in sleep-deprived subjects was significantly lower, which suggests a down-regulation in metabolism while sleep-deprived. However, more research needs to be done to determine the full extent of this association.
Sleep And Weight In Children
Of the eleven studies examined in the review article which covered children, sleep, and weight loss/gain, all eleven studies showed a positive association between short sleep deprivation and obesity. Studies were conducted all over the world with the same results, suggesting this association is not limited to certain ethnic groups. Limited studies have been done on causality between sleep and weight loss, but so far researchers have not found increased calorie consumption or decreased physical activity as a reason for increased weight with lack of sleep.
Sleep And Weight In Adults
Research examining the relationship between adults, sleep, and weight is more mixed. Most of the studies found an association between lack of sleep and weight gain, but not all studies agree. In fact, some research suggests the effect of sleep and weight may decrease with age. Two Japanese sleep studies had reverse results with lack of sleep and weight loss, suggesting there may be an ethnic difference in sleep and weight gain. Some studies have also shown African Americans having a higher risk of gaining weight due to lack of sleep compared to Caucasians.
What About Too Much Sleep?
If lack of sleep is associated with an increased risk for obesity, is getting extra sleep associated with losing weight? Not according to a 2008 study in Sleep.
Researchers studied over 260 subjects over six years. They found that subjects getting less than six hours of sleep and over nine hours of sleep both gained significantly more weight than subjects getting seven to eight hours of sleep per night. Short duration sleepers were at a 35% increased risk of having at least 5 kg of weight gain, and long duration sleepers had a 25% greater risk of having at least 5kg of weight gain.
This study and other studies with similar results suggest there may be an optimal sleep range for weight loss. One possible explanation for increased risk of obesity in long duration sleep is that total energy expenditure may be lower because of increased time sleeping.
The link of causality between sleep and weight gain is a fine line, and researchers are quick to point out that obesity is a multi-faceted condition. For instance, obesity often comes with various co-morbidities such as sleep apnea, arthritis, asthma, and heartburn. These co-morbidities can disrupt sleep and the lack of sleep may be attributed to them.
Most sleep studies self-reported data, and there can be error and subjectivity with self-reporting. Socioeconomic status may also play a role in sleep and weight gain. Lower socioeconomic groups often work long hours, off hours, and may not have the best sleep conditions at home.
So far, research suggests 7-8 hours of sleep per night is ideal. If you don't get that, even for one night, be aware that you may be hungrier than normal! Fill up on high-volume, non-calorie-dense foods like fruits, vegetables, broth soups, and legumes. And if you feel like skipping your workout because you are tired, try to go to the gym anyway--your body will thank you for it, and you might just sleep better too!
Klok M, Jakobsdotti rS, Drent M. The role of leptin and ghrelin in the regulation of food intake and body weight in humans: a review. Obes Rev. January 2007;8:21-34.
Schmid S, Hallschmid M, Jauch-Chara K, Born J, Schultes B. A single night of sleep deprivation increases ghrelin levels and feelings of hunger in normal-weight healthy men. J Sleep Res. September 2008;17:331-4.
Patel SR, Hu FB. Short sleep duration and weight gain: a systematic review. Obesity (Silver Spring). March 2008;16:643-53.
Chaput JP, DesprÃ©s JP, Bouchard C, Tremblay A. The Association Between Sleep Duration and Weight Gain in Adults: A 6-Year Prospective Study from the Quebec Family Study. Sleep. April 2008;31:517-23.