Restricting Food Intake to 10 Hours A Day Could Lead to Better Health

Burgers from The Standard Grill on display at the Food Network & Cooking Channel New York City Wine & Food Festival. The group that was limited to a 10-hour window remained lean and healthy. MIKE COPPOLA/GETTY IMAGES

Limiting the number of hours a day you can eat might improve health, according to a new study in mice.

Researchers at the Salk Institute in California discovered that mice lacking healthy metabolisms can be protected against obesity and some diseases when they can only eat during a 10-hour window. Published in Cell Metabolism on Thursday, the study found that health problems caused by disruptions to the body's biological clock, or circadian rhythm, can be corrected by following these food guidelines.

"For many of us, the day begins with a cup of coffee first thing in the morning and ends with a bedtime snack 14 or 15 hours later," Satchidananda Panda, a professor in Salk's Regulatory Biology Laboratory and the senior author on the paper, said in a statement. "But restricting food intake to 10 hours a day, and fasting the rest, can lead to better health, regardless of our biological clock."

The circadian rhythm is the physical, behavioral, and mental changes that occur due to the body's daily cycle, according to the National Institute of General Medical Sciences. This helps the body determine where and when certain genes should be active, such as the genes for digestion, which are more active earlier in the day.

In this study, when scientists disabled the genes that control the mice's circadian rhythms. Without a working clock, the mice were prone to diabetes, obesity, elevated blood cholesterol and fatty liver disease. These metabolic diseases can escalate when the animals eat fatty and sugary foods.

The scientists split the mice into two groups: one that had 24-access to food and another that had access to the same amount of calories, but only for 10 hours a day. The group that could eat at any time became obese and developed metabolic diseases, but the group that was limited to the 10-hour window remained lean and healthy, even though they lacked the biological clock and were thought to be destined to be unhealthy.

"From the previous study, we had been under the impression that the biological clock was internally timing the process of turning genes for metabolism on and off at predetermined times," Amandine Chaix, a staff scientist at Salk and the paper's first author, said in a statement. "And while that may still be true, this work suggests that by controlling the animals' feeding and fasting cycles, we can basically override the lack of an internal timing system with an external timing system."

This study suggests that the circadian clock tells animals when to eat and when not to eat. In humans, their circadian clock can be disrupted through something like shift work or genetic defects, leaving the person vulnerable for obesity and metabolic diseases. Additionally, the internal clock can weaken as a person ages. Next, the scientists hope to determine is restricting food intake to a certain window could reverse aging.

Panda said, "Many of us may have one or more disease-causing defective genes that make us feel helpless and destined to be sick. The finding that a good lifestyle can beat the bad effects of defective genes opens new hope to stay healthy."