Eating only during the day and fasting for at least 12 hours a day could be the secret to longevity. Anyway, this is the conclusion of a study in mice, published in Sciencewhich finds that, under certain conditions, the benefits of intermittent fasting increase when food is provided at certain times of the day, even extending the lifespan of rodents by 35%.
Calorie restriction or decreasing daily calorie intake by 30%
Eating less to live longer is the principle of calorie restriction. It’s simply about reducing your daily caloric intake by 30%, without going hungry or malnourished. “It is the most effective non-pharmacological intervention to increase life span.” in the organisms studied, such as mice or even non-human primates, say the researchers in Science. But the underlying mechanisms are still poorly understood. “Mealtime can also be key.”, raise the researchers. Because most of the studies that deal with caloric restriction are done in rats, which have the particularity of eating immediately the food that is presented to them. In classical protocols, the fast imposed on them was therefore long, at least 22 hours. However, this single administration at a specific time of day can reset certain metabolic signals in the body, set in the circadian rhythm (the 24-hour cycle of a day). The importance of the circadian cycle can already be seen in the simple criterion of weight: mice, nocturnal animals, gain more weight when they eat only during the day.
So finally, to live longer, should we eat little or eat little And at the right time? To separate the true from the false, the researchers divided the mice into five groups. All were under caloric restriction, the only difference being the time of meal(s). The first group ate during the day and night. The second and third ate just one meal, one early in the day and one early in the evening, to enforce a 22-hour fast. As for the last two, they received food regularly, one during the day and the other at night, to induce a 12-hour fast. A sixth group that ate ad libitum served as a control group.
Eating only during the day and fasting for at least 12 hours a day could be the secret to longevity. Anyway, this is the conclusion of a study in mice, published in Sciencewhich finds that, under certain conditions, the benefits of intermittent fasting increase when food is provided at certain times of the day, even extending the lifespan of rodents by 35%.
Calorie restriction or decreasing daily calorie intake by 30%
Eating less to live longer is the principle of calorie restriction. It’s simply about reducing your daily caloric intake by 30%, without going hungry or malnourished. “It is the most effective non-pharmacological intervention to increase life span.” in the organisms studied, such as mice or even non-human primates, say the researchers in Science. But the underlying mechanisms are still poorly understood. “Mealtime can also be key.”, raise the researchers. Because most of the studies that deal with caloric restriction are done in rats, which have the particularity of eating immediately the food that is presented to them. In classical protocols, the fast imposed on them was therefore long, at least 22 hours. However, this single administration at a specific time of day can reset certain metabolic signals in the body, set in the circadian rhythm (the 24-hour cycle of a day). The importance of the circadian cycle can already be seen in the simple criterion of weight: mice, nocturnal animals, gain more weight when they eat only during the day.
So finally, to live longer, should we eat little or eat little And at the right time? To separate the true from the false, the researchers divided the mice into five groups. All were under caloric restriction, the only difference being the time of meal(s). The first group ate during the day and night. The second and third ate just one meal, one early in the day and one early in the evening, to enforce a 22-hour fast. As for the last two, they received food regularly, one during the day and the other at night, to induce a 12-hour fast. A sixth group that ate ad libitum served as a control group.
35% longer shelf life with targeted daily calorie restriction
The results are surprising. While mice that ate continuously gained 10% life expectancy from calorie restriction alone, the groups that added overnight fasting gained 20%. Even better, mice that fasted during the day and ate at night, their natural period of activity, gained 35% life expectancy, or an additional nine months on an average life span of two years! “The surprising result is that reducing calories by 30-40% (which is very important) extends shelf life by only 10%.“, explains Sciences et Avenir Joseph Takahashi, first author of the study.”It is also surprising that feeding time is the most important factor (15% due to circadian alignment, 10% due to fasting, and 10% due to calories alone) of the three life expectancy factors..”
Whether the fast lasted 22 or 12 hours had no effect on its own, and the scientists concluded that a 12-hour fast during the period of lowest activity (at night for humans, for example) is enough to benefit the full potential of calorie restriction. . “Aging decreases the expression of genes related to metabolism and increases those of inflammation”, explain the study authors. Slowing down your metabolism yourself through a restrictive diet during times when your natural metabolism is at its highest, therefore, allows you to counterbalance this aging effect. “The circadian clock controls the metabolism of virtually every cell and tissue in the body.” highlights Joseph Takahashi. “It optimizes metabolism to process nutrients in one phase (active or awake phase), while in the opposite phase these pathways are less efficient.”
In humans, still scarce results that require caution
In humans, few results are still available. It is really complex to impose a controlled diet on people over the years. A study published in Science in February 2022, however, it lifted the lid on the consequences of a restrictive diet for our own species, imposing a 14% calorie restriction on 100 people for two years. If your life expectancy obviously couldn’t be measured, the researchers noted benefits in immunity. The thymus, a gland that produces white blood cells that loses efficiency with age, has been regenerated in dieters! On the other hand, studies reveal that adding caloric restriction and meal intake during the most active hours of the day (8 am to 4 pm in the study) has no effect on weight loss in obese humans.
Still, calorie restriction and fasting should be practiced with caution, otherwise you risk putting your life in jeopardy rather than prolonging it. “Extreme calorie restriction – a 40% reduction in calories – is associated with impaired immune function, which can lead to more serious infections.”, point out the American health authorities. Also, this practice is not recommended for weight loss as it promotes further recovery. “The cause: changes in energy metabolism and a decrease in metabolically active body mass (lean mass)”, explains Inser. The institute also points to the risks “for the health of bones, cardiovascular system and kidneys, as well as the possibility of psychological disorders such as anorexia/bulimia in case of a very strict diet”.