Friday, 26 May 2017

Lack of High-Quality Sleep May Contribute to Weight Gain

Getting a good night's sleep (or day's sleep for those with a night job) is important for many reasons. Research suggests that one of these reasons is to prevent or reduce weight gain. Over the last few years, researchers in different institutions have found a link between poor quality sleep and an increase in body weight. Though the exact reason for the link is unknown, several proposals have been made based on the evidence obtained so far. One of the leading theories is that the balance between chemicals that influence appetite and satiety is altered.


Adequate sleep is important.
Public domain photo by claudioscott


Some Possible Reasons for Weight Gain After Sleep Loss


Weight gain after inadequate sleep may be due to one or more factors, including changes in appetite, metabolism, motivation, or the desire for exercise. Researchers at Uppsala University in Sweden recently presented some interesting discoveries at the European Congress of Endocrinology in Lisbon. Some of their discoveries are described in the quote below.


Following sleep loss, normal-weight men prefer larger food portions, seek more calories, exhibit signs of increased food-related impulsivity, experience more pleasure from food, and expend less energy. Christian Benedict, Uppsala University
The researchers made some other interesting discoveries. They found that after sleep loss the level of hormones that promote appetite (such as ghrelin) increased and the level of those that promote satiety (such as glucagon-like peptide 1) decreased. Ghrelin is made by the stomach and glucagon-like peptide 1 is made by the intestine.


The Endocannabinoid System


Like some other scientists who have investigated the effects of sleep loss, the Swedish researchers also found that the level of endocannabinoids that increase appetite rose after lack of sleep. The endocannabinoid system was discovered relatively recently. It seems to be involved in the regulation of a variety of processes, including motivation, reward, and appetite control. It's composed of chemicals that act as signaling molecules and activate the same receptors as delta-9-tetrahydrocannabinol, or THC. THC is also found in marijuana (scientific name Cannabis sativa), which is known to increase appetite.


The Role of Gut Bacteria 


The researchers also claim that sleep loss alters the composition of the bacterial community in our gut. Scientists are discovering that this community seems to have important effects on our lives. Many of these effects are helpful. Some bacteria are harmful, but they are normally kept in check by the good bacteria. If the balance between "good" and "bad" bacteria is altered, we may develop a health problem.


Peer Review


Uppsala University is a respected institution, but at the time of this post their research hadn't yet been peer reviewed. A peer review is performed by researchers who work in the same area as the scientists whose work is being published. The review looks for obvious flaws in the research that make the report unsuitable for publication. Nevertheless, the results of the Swedish research are interesting. Since other scientists have had similar results to some of those made by the Uppsala team, the team's claims may well be accurate.



 A healthy diet as well as adequate sleep is needed to prevent weight gain.
                                               Photo by Linda Crampton


Tips for Getting a Good Night's Sleep 


Sleep experts have some suggestions for helping us rest properly during the night. They say that eating a heavy meal shortly before bed is not a good idea. Neither is drinking caffeine. Some people may need to avoid caffeine in the afternoon as well. Exercise close to bedtime may not be a good idea, either, but this varies in different individuals. Using electronic devices in bed—even small ones like a cell phone—is a bad idea. The light from the device can trick the brain into thinking that it's day time and stop a person from relaxing and falling asleep.

Researchers have pointed out that getting enough high-quality sleep probably won't be very helpful for weight loss if we make lots of poor diet choices or never exercise during the day. Combined with a healthy diet and adequate exercise, it could be very beneficial, however.



References


Sleep loss and weight gain: Uppsala University research


Lack of sleep and endocannabinoid level: University of Chicago research


Weight gain after insufficient sleep from the Mayo Clinic