Cutting calories and eating at the right time of day leads to longer life in mice

A recipe for longevity is simple, if not easy to follow: eat less. Studies in a variety of animals have shown that restricting calories can lead to a longer, healthier life.

Now, new research suggests that the body’s daily rhythms play a role in this longevity effect. Eating only during their busiest time of day substantially extended the lifespan of mice on a low-calorie diet, Howard Hughes Medical Institute investigator Joseph Takahashi and colleagues report May 5, 2022, in the journal Science.

In his team’s study of hundreds of mice over four years, a low-calorie diet alone extended the animals’ lives by 10 percent. But feeding the mice the diet only at night, when the mice are most active, prolonged lifespan by 35 percent. That combo — a low-calorie diet plus a nightly feeding schedule — added an extra nine months to the animals’ typical two-year average lifespan. For people, an analogous plan would restrict eating to daylight hours.

The research helps unravel the controversy surrounding diet plans that emphasize eating only at certain times of the day, says Takahashi, a molecular biologist at the University of Texas Southwestern Medical Center. These plans cannot accelerate weight loss in humansAs a recent study in New England Journal of Medicine informed, but could prompt health benefits which add up to a longer lifespan.

Takahashi’s team’s findings highlight the crucial role of metabolism in aging, says Sai Krupa Das, a nutrition scientist at the Jean Mayer USDA Human Nutrition Research Center on Aging who was not involved in the work. “This is a very promising and landmark study,” she says.

fountain of youth

Decades of research have found that calorie restriction extends the lifespan of animals ranging from worms and flies to mice, rats, and primates. Those experiments report weightlossimprovement of glucose regulation, low blood pressureand reduction of inflammation.

But it has been difficult to systematically study calorie restriction in people who cannot live in a laboratory and eat measured portions of food throughout their lives, says Das. He was part of the research team that conducted the first controlled study of caloric restriction in humans, called the Comprehensive Assessment of the Long-Term Effects of Reducing Energy Intake, or CALERIE. In that study, even a modest reduction in calories “was remarkably beneficial” in reducing signs of aging, Das says.

Scientists are just beginning to understand how caloric restriction slows aging at the cellular and genetic levels. As an animal ages, genes related to inflammation tend to become more active, while genes that help regulate metabolism become less active. Takahashi’s new study found that calorie restriction, especially when timed with the mice’s active period at night, helped offset these genetic changes as the mice aged.

matter of time

Recent years have seen the rise of many popular diet plans that focus on what’s known as intermittent fasting, such as fasting every other day or eating only for a period of six to eight hours per day. To tease out the effects of calories, fasting, and daily or circadian rhythms on longevity, Takahashi’s team conducted an extensive four-year experiment. The team housed hundreds of mice with automatic feeders to control when and how much each mouse ate throughout its life.

Some of the mice could eat as much as they wanted, while others were restricted in calories by 30 to 40 percent. And those on calorie-restricted diets ate at different times. Mice fed the low calorie diet diet at night, over a two-hour or 12-hour period, they lived longer, the team found.

The results suggest that time-restricted eating has positive effects on the body, even if it does not promote weight loss, since New England Journal of Medicine suggested study. Takahashi points out that his study also found no difference in body weight between mice at different feeding times, “however, we found profound differences in life expectancy,” he says.

Rafael de Cabo, a researcher in gerontology at the National Institute on Aging in Baltimore, says that Science role” is a very elegant demonstration that even if you are restricting your calories but you are not [eating at the right times]you don’t get all the benefits of calorie restriction.”

Takahashi hopes you learn how calorie restriction affects the body’s internal clocks as we age will help scientists find new ways to extend the healthy lifespan of humans. That could come from calorie-restricted diets or medications that mimic the effects of those diets.

Meanwhile, Takahashi is learning a lesson from his mice: he restricts their feeding to a 12-hour period. But, she says, “if we find a drug that can speed up your clock, we can test it in the lab and see if that spreads.” Life expectancy.”