JACC: If you don't get enough sleep, your stomach grows!

Friends who yearn for good body management but don't get enough sleep on a daily basis may need to beware, as new evidence has now added to the causal link between sleep deprivation and obesity
.

Recently, the team of Professor Virend K.
Somers from the Department of Cardiovascular Medicine, Mayo Clinic School of Medicine, published in the Journal of the American College of Cardiology the effect of sleep time restriction on energy intake, energy expenditure and fat storage.
The results of randomized controlled trials [1]
.

The results suggest that 2 weeks of sleep restriction increased the subjects' caloric intake by 17%, but there was no significant difference in energy expenditure, which increased the subjects' visceral fat accumulation by 11%
.

 Lack of sleep is a common social problem, and previous studies have suggested that there is a correlation between insufficient sleep and obesity, premature death, etc.
[2-3]
.

However, the idea that short sleep duration is a promoting factor of obesity is mostly derived from the inference of observational studies [4-5].
There are still few experimental studies on sleep deprivation and weight regulation, and the conclusions are divergent.
There are even fewer studies related to energy intake and expenditure [6-7]
.

Can sleep deprivation lead to increased fat storage? Most of the existing studies are limited by the limitations of short sleep pattern intervention time and inaccurate evaluation indicators of obesity, so it is difficult to give reliable answers
.

Considering that the health risks of visceral obesity are significantly higher than other obesity phenotypes [8], if reduced sleep does lead to increased fat storage, where is the extra fat stored? This is also an open and clinically important topic
.

Professor Virend K.
Somers' team designed a randomized, controlled, crossover, hospitalization trial to answer the effects of chronic sleep restriction on energy intake, energy expenditure, and fat storage areas in healthy, non-obese individuals
.

The researchers recruited 18-50 years old, BMI ≤30kg/m2, no smoking history, non-pregnant and lactating, no medical history, no long-term prescription drug use (except contraceptives, intrauterine devices and second-generation antihistamines) ) and healthy people with regular sleep patterns, stratified by gender, and randomly divided into a sleep restriction group and a control group in a 1:1 ratio
.

The sleep restriction group and the control group received two phases of intervention with a 21-day experimental protocol, each of which consisted of a 4-day adaptation period, a 14-day experimental period, and a 3-day recovery period.
There was a 3-month washout period, after which the 21-day trial protocol (crossover) was reversed to that of the first group
.

Subjects in the sleep-restricted group were allowed only 4 hours of sleep during one phase of the 14-day trial period, while the control group was allowed to spend up to 9 hours in bed
.

Trial grouping scheme All subjects were placed in a sedentary environment with an unlimited supply of food
.

The primary outcome of the study was defined as the mean change in daily calorie intake from the acclimation period to the trial period
.

Secondary outcomes included dietary macronutrients, resting and postprandial energy expenditure, non-exercise activity energy expenditure, physical activity, body weight, body composition, abdominal fat distribution, sleep duration, and appetite regulation biomarkers
.

A total of 12 eligible subjects completed the trial between May 2013 and May 2018
.

Compared to the acclimation period, energy intake in the sleep-restricted group increased by 17%, compared with only 6% in the control group
.

After correcting for differences in conditions, the sleep restriction group increased daily energy intake by 308.
1 kcal (95%CI: 59.
2-556.
8 kcal) compared with the acclimation period, and both protein and fat intake were significantly increased
.

Changes in energy intake and dietary component intake There were no significant differences in energy expenditure and basal metabolic rate between the two groups
.

The sleep restriction group had a higher net weight gain (0.
5kg, 95%CI: 0.
1-0.
8kg), although there was no significant difference in the total body fat percentage between the two groups, but the abdominal fat area of ​​the subjects during sleep restriction increased by 9%, while the control group did not increase, the relative increase was 15.
2c㎡ (95%CI: 3.
6-26.
8c㎡)
.

Comparison of Body Weight Change and Regional Fat Distribution The researchers subdivided abdominal fat into subcutaneous and visceral fat and found that subcutaneous fat increased significantly in both the sleep-restricted and control groups, but the net gain of subcutaneous fat was higher in the sleep-restricted group
.

There was no significant change in visceral fat in the control group, but it increased by 11% in the sleep restriction group, with a relative increase in visceral fat of 7.
8c㎡ (95%CI: 0.
3-15.
3c㎡)
.

This study demonstrated that insufficient sleep time can lead to increased energy intake, which in turn promotes weight gain, by conducting a cross-over sleep restriction trial in a healthy population
.

And the first analysis of the association between sleep deprivation and new fat distribution in the body proves that there is a significant causal relationship between sleep deprivation and visceral fat accumulation
.

Article Summary Fat accumulation in healthy adults following simple overeating usually begins under the skin
.

The increase in abdominal fat caused by lack of sleep in this study was mainly in the internal organs
.

This suggests that sleep deprivation combined with overeating may alter the mechanism of fat storage
.

Visceral fat is less sensitive to insulin, is a source of pro-inflammatory cytokines and an important risk factor for cardiovascular metabolism, and is also significantly associated with various adverse outcomes such as death [9-10]
.

This also makes the conclusions of this study have important public health value
.

Interestingly, lack of sleep also changed food preferences, with the sleep-restricted group eating more protein and fat in this study
.

Furthermore, the additional wake-up time did not significantly increase energy consumption, and the peripheral endocrine regulation mechanism did not compensate for the extra calorie intake, suggesting that reduced sleep may lead to pathological changes in the body's metabolism
.

The advantage of this study is that the influence of individual differences between groups was excluded through randomized control and crossover design, and the accuracy of causal inference was ensured
.

The 14-day sleep restriction enhanced the convincing conclusion, the unrestricted access to food was more in line with the real-world characteristics, and the collection of a large number of research indicators made the conclusion analysis accurate and comprehensive
.

At the same time, this study also has some shortcomings, such as: the sample size is relatively small, and the subjects are mainly male, the metabolic changes caused by the relatively brief 2 weeks of sleep restriction and the actual characteristics of the chronic insomnia population may be different different
.

The influence of the biological clock on the research conclusions may not be completely excluded, and the interaction between sleep restriction and food types and nutritional quality needs to be further clarified in future studies
.

At a time when study and work are constantly involuted, the shortening of sleep time is becoming more and more common, and the ultra-long commute has forced countless workers to "morning the waste and returning home with the moon and lotus", and researchers fought hard until late at night.
It is also a normal operation
.

It has long been commonplace for sleep to be forced to sacrifice for the few personal lives it has
.

But as everyone knows, when you press the brake button to rest your body, metabolic abnormalities will gradually emerge
.

Trying to get 7-9 hours of normalized sleep and limiting energy intake during sleep-depleted periods may reduce the health risks associated with sleep deprivation
.

However, according to the findings of this study, visceral fat continued to accumulate during the 3-day recovery period after sleep restriction.
Friends who want to make up for the lack of sleep on weekdays by supplementing sleep on weekends may not be able to do so
.

Although it is difficult to achieve easily, I hope that everyone can unload the burden of work and study in time and enjoy the sweetness of a night's sleep
.

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Jayedi A, Soltani S, Zargar MS, Khan TA, Shab-Bidar S.
Central fatness and risk of all cause mortality: systematic review and dose-response meta-analysis of 72 prospective cohort studies.
BMJ.
2020;370:m3324.
Published 2020 Sep 23.
doi:10.
1136/bmj.
m3324 Editor of this article | Dai SiyuPhysiol Rev.
2013;93(1):359-404.
doi:10.
1152/physrev.
00033.
201110.
Jayedi A, Soltani S, Zargar MS, Khan TA, Shab-Bidar S.
Central fatness and risk of all cause mortality: systematic review and dose-response meta-analysis of 72 prospective cohort studies.
BMJ.
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Published 2020 Sep 23.
doi:10.
1136/bmj.
m3324 Editor of this article | Dai Siyu