Time-restricted eating (TRE) involves a regular, 24-hour cycle of eating and fasting, with meals, snacks, and sugary drinks strictly limited to the same 8–10 hour window each day.
TRE is a form of intermittent fasting (IF) in which people can eat what they like during a set period but must fast for the rest of the time.
Scientists believe the TRE protocol improves health and well-being by reinforcing the body’s natural daily cycle of rest and activity, but how it works at a molecular level has been unclear.
A new study in mice shows that time-restricted feeding (TRF) influences the activity of genes in 22 diverse tissues all over the body, including the brain, heart, lungs, liver, and gut.
The researchers report their results in Cell MetabolismTrusted.
Time-restricted eating: What are the benefits?
A 2022 review of research notes that pilot studies in humans suggest that the health benefits of TRE include improvements in obesity, diabetes, and cardiovascular disease. The diet may also improve sleep and mental health.
In addition, another recent study in mice found that the eating pattern may even have anticancer effects.
Crucially, the health benefits of TRE compared with eating at any time during the day appear to apply regardless of the total calories or types of food consumed.
Time-restricted feeding changes gene expression
For the present study, the researchers allowed a control group of mice to eat whenever they liked, while a second group only had access to food during a 9-hour period.
Both groups ate the equivalent of a western diet and consumed the same number of calories overall.
After 7 weeks, the researchers took samples from 22 organs and brain regions every 2 hours over a 24-hour period.
The samples included tissue from the stomach, intestines, liver, lungs, heart, adrenal gland, hypothalamus, kidney, and brain.
Compared with the control group, TRF changed overall gene expression (the rate at which genes generate proteins) or the rhythmic activity of around 80% of all mouse genes.
Effects on circadian rhythms
The TRF diet orchestrated daily fluctuations in gene expression across all the tissues. This reinforced the body’s circadian rhythms, which are its natural cycles of rest and activity. Circadian rhythms are everywhere in every cell.
The researchers found that time-restricted eating synchronized the circadian rhythms to have two major waves: one during fasting, and another just after eating.
Interestingly, TRF reduced the activity of genes that play a role in inflammation and increased the activity of those involved in autophagy — the recycling of old and damaged cell parts. Increased autophagy (only during the fasting period) is known to improve health by preventing and managing age-related diseases and increasing healthspan.
Increased inflammation and reduced autophagy are recognized hallmarks of biological aging.
TRE benefits in humans: An area of ongoing research
The researches said that the vast majority of adults in the United States have an “erratic” eating pattern, with meals, snacks, and sugary drinks consumed over more than 12 hours each day.
TRF is known to improve gut microbiome, liver health, glucose regulation, muscle function (increased endurance capacity), sleep quality, cognitive function, and resilience against infectious diseases. Therefore, it applies to everyone to stay healthy and achieve their peak physical and emotional performance.