Can time-restricted eating improve metabolic function? New scientific evidence →

Nowadays, many people have disordered eating habits, eating late dinner or often eating midnight snacks. This bad habit will disrupt the circadian rhythm and increase the risk of metabolic diseases such as obesity and fatty liver. At this time, weight loss is put on the agenda.

Many friends who want to lose weight have implemented the "16+8" (8-hour eating method): that is, divide the 24 hours of a day into two parts, do not eat for 16 hours, and control the eating time to 8 hours. For example, choose to eat at a fixed time from 8 am to 4 pm, or from 9 am to 5 pm. In addition to drinking water, no additional caloric food is consumed during the rest of the time. This eating pattern is called time-restricted eating. Of course, time-restricted eating is not limited to an 8-hour pattern. There are patterns from 4 to 12 hours. The familiar "5+2" (5 days of normal diet, 2 days of controlled diet) pattern is also a type of time-restricted eating.

Some studies suggest that limiting the time of daily meals can reduce energy intake to a certain extent, while prolonging fasting time, which helps lower insulin levels and reduce fat synthesis. When the body's glycogen reserves are exhausted, it starts burning fat for energy, which helps increase the basal metabolic rate in the long run. However, its scientific validity remains to be determined.

Recently, teams from Peking University and Capital Medical University jointly published a paper in the international journal Cell Metabolism, revealing the scientific mechanism of time-restricted diet in improving metabolic dysfunction. The researchers found that time-restricted diet increases Ruminococcus contortus in the intestine, and its product 2-hydroxy-4-methylvaleric acid can inhibit the activity of the intestinal hypoxia-inducible factor 2α-ceramide pathway, thereby improving liver inflammation and fibrosis.

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The researchers recruited 19 patients with fatty liver disease associated with metabolic dysfunction and conducted a small-scale clinical intervention trial. Participants implemented a time-restricted diet for 4 weeks, limiting their eating time to between 7 am and 5 pm each day, with only 10 hours available for eating.

The researchers analyzed the participants' stool and plasma samples before and after the experiment and found that after four weeks of time-restricted diet, the levels of plasma alanine aminotransferase, aspartate aminotransferase, and gamma-glutamyl transferase, which reflect the degree of liver damage, were significantly reduced, indicating that the participants' liver condition was much better. In addition, the participants' liver fatty degeneration index improved significantly, serum triglyceride levels decreased significantly, and body mass index also decreased.

Afterwards, the researchers conducted metagenomic sequencing on the participants' stool samples and found that the composition and abundance of intestinal bacteria changed significantly before and after the time-restricted diet intervention. The most significant increase in the strain after the intervention was Ruminococcus contortus. As mentioned earlier, this bacterium can inhibit the activity of the intestinal hypoxia-inducible factor 2α-ceramide pathway. Hypoxia-inducible factor 2α is an important regulatory factor in the human body, mainly present in endothelial cells.

It is understood that some previous studies at home and abroad have also shown that hypoxia-inducible factor 2α plays an important role in hypoxia adaptation, erythropoiesis, liver growth and other physiological aspects. In other words, it is the main transcription factor for intestinal iron absorption, which can promote the hypoxia adaptation of organisms and increase the iron storage protein - ferritin, thereby reducing the host's intestinal absorption of iron.

In addition, time-restricted eating may also clear damaged cellular components by affecting mechanisms such as cellular autophagy, thereby helping to reduce inflammatory markers in the body, alleviate chronic inflammatory states, reduce the risk of inflammatory-related diseases such as cardiovascular disease and arthritis, and to a certain extent delay the process of cellular and body aging.

(The author Ren Shengquan is a member of the Anhui Science Writers Association and a health manager)