Nuevo ensayo concluye que dormir más adelgaza

octubre 9, 2023

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Little and irregular sleep has been associated with overweight on numerous occasions, but almost always through observational studies, such as in the following systematic reviews:

Certainly, intervention studies have also been published analyzing the possible effects of sleep on body weight, as reported in these other reviews:

As I have already said in previous posts, this other type of research also suggests that lack of sleep is a risk factor for being overweight and that lengthening its duration could have a favorable influence in this regard. But the truth is that the results are less clear and the evidence is not very abundant. Therefore, the publication of more rigorous trials on this topic is appreciated, to know if it is necessary to consolidate sleep as one of the key variables when it comes to preventing and treating obesity.

Like the essay we learned about this week in JAMA, Effect of Sleep Extent on Objectively Assessed Energy Intake Among Overweight Adults in Real-Life Settings (2022). This is an investigation carried out by North American experts involving 80 people aged 20 to 40, who were somewhat overweight (without becoming obese) and who slept rather little (less than 6.5 hours a day). The researchers divided the participants into two groups and after two weeks of unchanged monitoring, participants in the intervention group were given support and advice to try to lengthen their sleep time to 8.5 days. This period also lasted two weeks and participants in both groups were monitored using digital bracelets, in order to obtain objective data on their activity and sleep time. In addition, their total energy expenditure was measured using the double marked water methodalso at rest indirect calorimetryas well as the thermogenic effect of food.

After completing the trial and carrying out the pertinent analyzes and calculations, the researchers have represented the results of all the participants in clarifying graphics that you can see below (in orange the control group and in blue the intervention group, click to enlarge) .

First about changes in sleep duration:

As can be seen, people in the control group (graph A) maintained their average sleep time close to 6 hours a day, while those in the intervention group (graph B) increased it by approximately just over an hour, for over 7 hours a day.

And secondly we can see the changes in the energy ingested:

It can be seen how in the control group (orange) approximately half of the people slightly increased their sleep time and the other half reduced it (graph C); and the majority increased their energy intake (graph D). However, in the intervention group (blue) the vast majority increased their sleep time (graph D) and also reduced their energy intake (graphs B).

The publication includes the following graph as a final summary, with the changes in energy intake of both groups (control on the left and intervention on the right):

The authors summarize their conclusions like this:

«(…) participants in the intervention group had a statistically significant weight reduction compared to those in the control group (−0.87 kg). In the control group there was an increase in weight compared to the initial weight (0.39 kg) and in the intervention a reduction (-0.48 kg).

(…) lengthening the sleep time of overweight and short sleepers reduced energy intake and resulted in a negative energy balance (energy intake lower than expenditure) in a real environment. To our knowledge, this study provides the first evidence of the beneficial effects of lengthening sleep on energy intake and body weight, objectively assessed in participants who will continue to live in their familiar environment. (…) «

A really interesting study and results, which must be confirmed in other trials, better if they are of longer duration.

And to those most interested I recommend, as always, consult the original studywhich fortunately is freely accessible.

Update: