November 9, 2021 – Eating a single meal daily can provide longevity and metabolic benefits, much like those seen with calorie restriction, according to new findings in mice.
Previous mouse studies have linked calorie restriction to healthier aging and are bound long daily fast on metabolism changes associated with a longer lifespan. Because mice in those studies typically ate only once a day, the results reflected the effects of both calorie restriction and daily fasting. For the new experiment, published in Nature Metabolism, scientists have sought a clearer picture of how fasting on its own can affect health benefits associated with calorie restriction.
To do this, scientists separated male mice for 4 months into four different diet groups, reflecting fasting and calorie restriction together and separately. Mice in the totally unrestricted group ate what they wanted during the day as they wanted, as a control. A second group represented fasting without calorie restriction, eating as much as possible within 3 hours each day and fasting for the remaining 21 hours.
The other two groups of mice’s calories were limited by about 30%. One group, representing only calorie restriction, was fed three equally large meals evenly distributed throughout the day. The other group combined both factors; the mice are trained to eat all their calorie-restricted foods in a single meal breakfast, with no more food for the rest of the day.
The mice that ate all their food in a single breakfast, whether calorie restricted or not, had lower blood sugar, better use of fat stores for energy, less fragility as they age, and longer life.
Although blood sugar levels decreased in mice on unlimited calorie restriction, these animals also died on average about 8 months earlier than their calorie-restricted, fasting counterparts.
In other words, these results in mice suggest that an extended daily fasting period offers similar benefits as calorie reduction. But whether these patterns apply to humans is not known.