The complex effects of dietary restriction on longevity and health

Abstract

Calorie restriction is known to extend lifespan in a wide range of species; however, the effects are variable and findings from animal models are often not applicable to humans, as the calorie restriction regimes are generally difficult to adhere to in the real world. Now, a paper has explored the effects and underlying mechanisms of several different methods of calorie restriction and dietary restriction in a genetically diverse mouse model, including dietary patterns that can be more realistically adhered to in the general human population.

From 6 months of age, 937 female mice were randomly assigned to one of five groups: ad libitum feeding; one day per week of fasting; two consecutive days per week of fasting; 20% calorie restriction; and 40% calorie restriction. The mice were kept on the diet for the duration of their natural lives. Mice in the intermittent fasting groups demonstrated compensatory feeding after the fasting period, such that mice in the one-day fast group consumed a similar amount to the mice in the ad libitum group and mice in the two-day fast group consumed 12% less. The mice in the two calorie restriction groups received their allotment of food for the weekend on Friday afternoons, and had typically consumed it by Saturday afternoon (40% calorie restriction) or Sunday afternoon (20% calorie restriction), which resulted in weekly fasting periods. The mice were also monitored in metabolic cages at three time points: ~5, ~16 and ~26 months old.