September 13, 2021 by archyde
How does obesity risk if people with an inflexible metabolism burn more carbohydrates instead of fat at night? (Image: Tartila / stock.adobe.com)
Obesity from Impaired Fat Burning?
So-called metabolic flexibility plays an important role in which source the body draws its energy from. An inflexible metabolism during sleep seems to result in more carbohydrates being burned than fat and the development of obesity being favored.
The human body can switch metabolic energy sources in response to changes in nutritional status. During the day, carbohydrates, fats and proteins are broken down by the metabolic process. Most of the energy comes from carbohydrates immediately after a meal, while most of the energy comes from fats after fasting, according to experts at the University of Tsukuba from their latest study results. The corresponding study was published in the English-language specialist journal “Nature“Read.
What is Metabolic Flexibility?
The body’s ability to switch metabolic energy sources in response to changes in nutritional status, such as after meals and during sleep, is known as metabolic flexibility, according to the researchers.
Diseases caused by impaired metabolic flexibility
A disturbed metabolic flexibility is associated with diseases such as obesity and Diabetes, connected. In the new study, the metabolism during sleep was examined in particular.
“We were interested in how the metabolism changes during sleep and whether we can detect differences in metabolism in people with an inflexible metabolism,” explains study author Professor Kumpei Tokuyama in one Press release.
What is used as an energy source?
The team used a measurement called the respiratory quotient (RQ) as the basic method for the investigation. This is the ratio between exhaled CO2 (carbon dioxide) and the O2 (oxygen) absorbed by the body. If the two amounts are the same (an RQ is 1), this signals that the energy source is carbohydrates. If the ratio is lower (around 0.8), on the other hand, this indicates that fats or proteins are being used as an energy source, explain the experts.
To characterize the changes in metabolism over time, the researchers measured the carbon dioxide-oxygen ratio of a total of 127 people every five minutes over a period of 24 hours.
Is sleep like a period of fasting?
Gives sleep actually resembles a fasting period, one could expect the RQs to decrease throughout the night, which suggests that more and more fat is burned as sleep progresses, the team said.
Instead, the experts found that the RQ values fell steadily at the beginning of sleep, but rose again after reaching a low point after midnight and continued to increase until waking up.
Then the participants were divided into two different groups, depending on how much their RQ values fluctuated. A high variability means that the metabolism is flexible and the RQ values rise and fall as the body needs it during the day, explain the researchers.
Poor fat burning thanks to an inflexible metabolism
After dividing the participants into a group with a flexible and a group with an inflexible metabolism, the team finally found that although the average RQ values over 24 hours were the same between the groups (as well as their age, BMI and body fat percentage ), the RQ values at night were higher in the participants with less flexible metabolism, suggesting that these people burned more carbohydrates than fat.
Obesity and Diabetes Prevention
Experts believe that it is precisely these findings that could prove very useful in the future, since the prevention of diseases such as obesity and diabetes is much better than their treatment. “Annual check-ups, which focus on measuring sleep RQs, could help identify people at risk for developing metabolic diseases and enable timely interventions,” added Professor Tokuyama. (as)
Author and source information
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This text complies with the requirements of specialist medical literature, medical guidelines and current studies and has been checked by medical professionals.
- Simeng Zhang, Yoshiaki Tanaka, Asuka Ishihara, Akiko Uchizawa, Insung Park, et al.: Metabolic flexibility during sleep; in: Nature (veröffentlicht 08.09.2021), Nature
- University of Tsukuba: Potential indicator for obesity risk detected during sleep (veröffentlicht 08.09.2021), University of Tsukuba
This article is for general guidance only and is not intended to be used for self-diagnosis or self-treatment. He can not substitute a visit at the doctor.