En español | Time-restricted eating (TRE), a dietary regimen that restricts eating to a specific set of hours, isn't just about weight loss.
In experiments on laboratory mice (both young and old, of both sexes), scientists at the Salk Institute for Biological Studies in La Jolla, California, found the technique may help humans with frailty, type 2 diabetes, fatty liver disease, cancer and infectious diseases such as COVID-19.
"For many TRE clinical interventions, the primary outcome is weight loss, but we've found that TRE is good not only for metabolic disease but also for increased resilience against infectious diseases and insulin resistance,” Satchidananda Panda, a professor in Salk's Regulatory Biology Laboratory, said in a statement.
The scientists fed a high-fat, high-sugar diet to male and female mice of two age groups (equivalent to 20- and 42-year-old humans), restricting eating to nine hours per day — similar to a popular method of intermittent fasting that restricts eating to an eight-hour window each day.
They then ran medical tests to see what impact the time restriction on eating had on the mice. The results were published in the journal Cell Resources.
Researchers were surprised to find that male mice on a TRE diet were able to “preserve and add muscle mass” and “improve muscle performance.” Although the result didn't hold for female mice, the researchers note that older adults at risk of falls could benefit from improved muscle performance. Panda said he hopes additional studies can answer whether TRE helps muscles repair and regenerate better, as well as what impact TRE has on muscle metabolism.
2. Fatty liver disease
Regardless of age, sex or weight-loss profile, the researchers found that TRE “strongly protected” mice against fatty liver disease, a condition that affects up to 100 million Americans.
"This was our first time studying female mice, and we weren't sure what to expect,” study coauthor Amandine Chaix, a former staff scientist in the Panda lab and now an assistant professor at the University of Utah, said in a statement. “We were surprised to find that, although the females on TRE were not protected from weight gain, they still showed metabolic benefits, including less-fatty livers and better-controlled blood sugar."
The researchers suggest TRE may be “a low- or no-cost, user-friendly way” to regulate glucose, noting that over 40 percent of Americans are already diabetic or prediabetic.
"TRE was associated with a lower increase in blood glucose and a faster return to normal blood sugar levels in both young and middle-aged males, with a significant improvement in glucose tolerance in young and middle-aged females. Similarly, middle-aged females and males on TRE were able to restore normal blood sugar levels more efficiently than control mice, who had food available at all times,” they wrote.
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4. Liver cancer
Aside from diabetes, glucose intolerance can lead to nonalcoholic fatty liver disease and liver cancer, which the researchers note is “one of the few cancers whose incidence and death rates have increased, rather than declined, in the past 25 to 30 years."
As part of the study, the researchers administered a toxin that induced a sepsis-like condition in the mice. The mice were examined 13 days later, and those fed a TRE diet — both male and female — were still alive. The finding could be important given that during the pandemic sepsis-induced death is a particular danger in hospital intensive care units. Studies suggest septic shock as the cause of death for between 15 percent and 27 percent of hospital patients who die with severe COVID-19.
Peter Urban is a contributing writer and editor who focuses on health news. Urban spent two decades working as a correspondent in Washington, D.C., for daily newspapers in Connecticut, Massachusetts, Ohio, California and Arkansas, including a stint as Washington bureau chief for the Las Vegas Review-Journal. His freelance work has appeared in Scientific American, Bloomberg Government and CTNewsJunkie.com.