New research in mice suggests that restricting access to food to 8-12 hours rather than allowing constant access to food may help prevent and even reverse obesity and type 2 diabetes. The results of two studies publishing online December 2 in the Cell Press journal Cell Metabolism suggest that this time-restricted eating affects the balance of bacteria found in the gut. Researchers also found the occasional "cheat days" on weekends did not undo the benefits of time-restricted eating in mice.
Previously, investigators led by Dr. Satchidananda Panda of the Salk Institute for Biological Studies in La Jolla, California found that such time-restricted feeding may help prevent obesity caused by high-fat diets, but they didn't test its effects in the face of other nutritional challenges or pre-existing obesity.
In their new studies, the researchers tested time-restricted feeding in mice under diverse nutritional challenges. In mice fed a variety of high-fat and high-sugar foods, the strategy could help prevent the development of metabolic problems, and the benefits were proportional to the duration of fasting in the animals. Interestingly, the protective effects were maintained even when the mice were given "cheat days," when time-restricted feeding was temporarily interrupted by allowing the mice free access to food during the weekends, a protocol that would seem particularly relevant to humans. Finally, time-restricted feeding halted or reversed the progression of metabolic diseases in mice with pre-existing obesity and type 2 diabetes.
"We found that animals fed within a window of 8 to 12 hours had a number of protective and therapeutic health benefits compared with animals allowed to eat the same number of calories from the same food source at any time," says Dr. Panda.
In a second study, the scientists looked at the effects of different eating patterns on bacteria that reside in the gut. These bacteria, which make up what's known as the gut microbiome, are known to affect the body's metabolic processes. Dr. Panda and his team found that the gut microbiome is highly dynamic, exhibiting daily cyclical fluctuations in the proportions of different bacteria. Diet-induced obesity perturbed many of these cyclical body clock bacteria fluctuations, which were, however, partially restored by time-restricted feeding.
"The effect of eating time to nudge the gut microbiome and host physiology towards health or disease without altering genes, nutrients, calories, or drugs opens new research avenues and cost-effective health-care strategies," says Dr. Panda. "For biologists, this offers a novel paradigm to understand the etiology of metabolic diseases and undesirable gut microbiomes in modern lifestyles marked with erratic eating patterns." For public health and patient care, the results will prompt new studies to test if a change in eating patterns is a cost-effective first step towards prevention and treatment of obesity-related metabolic diseases.
Cell Metabolism, Chaix et al.: "Time-Restricted Feeding Is a Preventative and Therapeutic Intervention against Diverse Nutritional Challenges"
Cell Metabolism, Zarrinpar et al.: "Diet and Feeding Pattern Determine the Diurnal Dynamics of the Gut Microbiome"