Eating less often improves rodent health and lifespan than simply eating less, according to a study on Monday.
Researchers who looked at mice on different diets found that those who received fewer calories from a single daily diet lived longer than mice who ate the same number of calories distributed throughout the day.
The study, published in Nature Metabolism, showed that mice who ate only once a day also showed improved metabolism.
Study author Dudley Lamming of the University of Wisconsin told AFP scientists have known for about a century that calorie restriction prolongs the lifespan of rodents.
But earlier studies on mice and calorie restriction had included involuntary fasting with mice typically fed only once a day.
Lamming’s team decided to find out if the timing between feedings could play a role – and found that it wasn’t the amount of food alone that mattered.
“Instead, low-calorie diets ensure that mice are fasting much of the day – and this enforced fasting period (when we eat) is critical for the benefits of calorie restriction for life and health. “
Lamming’s team put the mice on different diets, with a control group having unlimited access to regular food.
Two other groups had 30 percent calorie restriction, one having access to low-calorie foods throughout the day and the other receiving 30 percent less regular food in a single feed with a 21-hour fast.
The study shows that mice on a low-calorie diet with 21 hours between meals lived about six months longer than mice who ate as much as they wanted at all times of the day.
In contrast, mice with constant access to a low-calorie diet lived slightly shorter lives than the control group, even though they consumed fewer calories.
“The enforced fasting period is essential for the benefits of a low-calorie diet,” Lamming said.
A final group of mice were trained to eat a similar amount of food as the control, but over a three hour period followed by a long daily fast.
– Humans? Not so fast –
Although their longevity was not measured, the mice in the latter group – who fasted without reducing their calorie intake – showed as many health benefits as the group who ate fewer calories and fasted.
“(Both groups) are better able to regulate their blood sugar and better adapt their metabolism to different demands during the day,” said Lamming.
Mice on a calorie-restricted diet that ate throughout the day did not show benefits such as better blood sugar control, better strength in old age, and longer life.
Diets that include intermittent fasting are popular among celebrities from Hugh Jackman to Kourtney Kardashian.
But Lamming points out that while short-term human studies seem to confirm that restricting food intake to a window of four to eight hours a day “appears to have certain benefits,” the long-term consequences remain unknown.
“We still don’t know the best time of day to fast, if different people might react differently to fasting or time-limited eating,” he added.
Reacting to the results, Stephen O’Rahilly, director of the MRC’s Metabolic Diseases Unit at Cambridge University, said they would be difficult to apply to humans given the huge differences in the rates at which the two species process. Food.
“A comparable human experience would require humans to eat all the calories they need for a week in one day, then starve for the next 6 days,” he said.
“As mice live about 2 years and we now live to about 80 years old, we may need to do the study for over 50 years to test whether such a big change in our eating habits actually benefited the human longevity, ”he added.
Lamming noted a takeaway for our species: People who are already reducing their daily calorie count by 20% or 30% may consider limiting the time they take these meals.
“If our results apply to people, they could lose some of the benefits of calorie restriction by spreading their meals out throughout the day,” he said.
© 2021 AFP