Lack of sleep first fat belly! For the first time to monitor the distribution of body fat in people with lack of consciousness, the area of abdominal fat increased by 7.8cm!

"Sleep takes up almost a third of a person's life and is an essential part of human health."

I don't know when sleep deprivation seems to have become a cliché for the post-80s, 90s and even 00s. From the 30+ company white-collar workers down to the 15- and 6-year-old student parties, the younger generation is "riding the dust" on the road to late sleep. "Stay up the night at the latest, apply the most expensive mask", "sleep at four o'clock, from six o'clock, lie in the ICU and drink millet" The witty tone often contains helplessness and calmness about "night life".

The newly released 2022 China Sleep Research Report points out that in the mainland, most people do not sleep enough. According to the survey results of the report on the basic sleep of mainland residents, 64.75% of residents actually sleep less than 8 hours a day, and the proportion of sleep more than 8 hours is only 7.97%; the average sleep time of all residents is only 7.06 hours per day. In addition to the "serious" reasons for study and work, smartphone use is the main culprit of most people's "sleep delays".

Adequate sleep is known to be important for brain function (such as memory), staying hydrated, preventing dementia, and many other psychological and physical health causes. But you know what? Sleep can also affect your body's metabolism and even determine your fat and thin!

In February, researchers at the University of Chicago School of Medicine in the United States published a randomized clinical trial study in the sub-journal JAMA that showed that patients with lack of sleep could reduce their caloric intake by increasing their sleep time, which helped to lose weight.

(Image source: JAMA Internal Medicine)

In the study, the researchers recruited 80 overweight volunteers around the age of 30, all of whom slept less than 6.5 hours a night on average. Subsequently, the participants were randomly divided into 2 groups and the intervention group was improved in sleep, resulting in an increase of 1.2 hours of sleep per night.

The results found that the intervention group reduced total caloric intake by an average of 270 kcal per day after an increase of 1.2 hours of sleep time per night compared with the control group. The researchers even predicted that if they could maintain healthy sleep habits for a long time, these overweight volunteers could lose 12 kilograms in 3 years!

Effect of sleep on indicators such as energy intake. (Image source: JAMA Internal Medicine)

If lack of sleep in this study only increased calories, it did not have a substantial effect on the body. Then in the next study, sleep deprivation leads to the accumulation of visceral fat, and the adverse consequences directly change from "quantitative change" to "qualitative change"!

Recently, researchers at The Mayo Medical Center published a research paper titled Effects of Experimental Sleep Restriction on Energy Intake, Energy Expenditure, and Visceral Obesity in the Journal of the American College of Cardiology (JACC). This randomized cross-controlled clinical trial found that sleep deprivation promotes the accumulation of abdominal fat, especially visceral fat, in young adults and triggers an increased risk of cardiovascular and metabolic diseases.

(Image source: J Am Coll Cardiol)

The researchers recruited 12 healthy people (including 9 men and 3 women) who were not obese, aged between 19-39 years, and participants were randomly assigned to either a control group (normal sleep) or a restricted sleep group. All participants underwent two 21-day experimental cycles, each of which was divided into a 4-day adaptation period, a 14-day experimental period, and a 3-day recovery period. Throughout the study, each group was free to choose their food. The researchers then monitored their energy intake, energy consumption, weight, body composition, fat distribution, and more.

During the 4-day adaptation period, all participants were asked to sleep 9 hours. For the next two weeks of the experiment, the sleep limit group slept for 4 hours, while the control group still slept for 9 hours. This was followed by a three-day, three-night recovery period in which both groups of subjects recovered 9 hours of sleep.

Experimental cycle. (Image source: J Am Coll Cardiol)

Interestingly, during the sleep restriction period of 4 hours, subjects consumed more than 300 additional calories per day, and their intake of protein and fat increased by about 13% and 17%, respectively, compared to the adaptation phase. This increase in consumption peaks early in sleep deprivation and then gradually declines to the starting level during the recovery period. Energy expenditure remains essentially the same throughout the process.

Changes in energy intake and dietary makeup. (Image source: J Am Coll Cardiol)

On the other hand, during the sleep restriction period, both the test group and the control group increased their body weight, but the test group increased even more, and the net weight increased by 0.5 kg. Differences in weight gain were maximized in the mid-trial period and dissipated during the recovery period.

Weight changes. (Image source: J Am Coll Cardiol)

So, where exactly does the increased fat from lack of sleep go?

Here, for the first time, the researchers examined the relationship between sleep deprivation and the body's body fat distribution: a CT scan detected changes in abdominal fat and visceral fat in participants. The results showed that sleep deprivation led to a 9% increase in total abdominal fat and an 11% increase in abdominal visceral fat. The time trajectory of abdominal fat deposition was assessed also to show that during the sleep restriction period, the expansion of subcutaneous and visceral fat appeared very early and continued into the recovery period, while the increase in subcutaneous fat occurred later during sleep restriction.

Changes in fat distribution. (Image source: J Am Coll Cardiol)

In response to this phenomenon, the researchers said, "Under normal circumstances, fat is preferentially deposited under the skin. However, sleep deprivation seems to divert fat to more dangerous visceral areas. What's more, despite a decrease in caloric intake and weight during restorative sleep, visceral fat will continue to increase. This suggests that sleep deprivation is a previously unrecognized trigger for visceral fat deposition. ”

+7.8cm Visceral fat in the abdomen (Image: J Am Coll Cardiol)

And it's wrong to measure the health effects of sleep deprivation solely by weight. "Our findings suggest that even in young, healthy, relatively slender subjects, shorter sleep duration was associated with increased caloric intake, a slight increase in weight, and a significant increase in abdominal fat accumulation." Lead investigator Virend Somers, PhD in cardiovascular medicine, said.

(Image source: Internet)

bibliography

[1] Tasali E, Wroblewski K, Kahn E, Kilkus J, Schoeller DA. Effect of Sleep Extension on Objectively Assessed Energy Intake Among Adults With Overweight in Real-life Settings: A Randomized Clinical Trial. JAMA Intern Med. 2022 Feb 7: e218098. doi: 10.1001/jamainternmed.2021.8098.

[2] Naima Covassin, Prachi Singh, Shelly K. McCrady-Spitzer, Erik K. St Louis, Andrew D. Calvin, James A. Levine, Virend K. Somers, Effects of Experimental Sleep Restriction on Energy Intake, Energy Expenditure, and Visceral Obesity, Journal of the American College of Cardiology. 79 (2022) 1254-1265. https://doi.org/10.1016/j.jacc.2022.01.038.

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