The latest research doesn’t have anything to do with the types of food you eat. Instead, it focuses on when you eat. One study found you should only eat in a 12-hour period during the day and fast the other 12 hours. The other study recommended fasting for 16 hours one day a week and a mini-fast (no more than 600 calories) for the rest of that day. The goal of these dietary changes isn’t to lose weight (though that often is a by-product) but to improve overall health. The research still is new, and most of it still is focused on mice rather than humans.
“Time-restricted eating didn’t just prevent but also reversed obesity,” says Satchidananda Panda, an associate professor at the Salk Institute who oversaw the studies. “That was exciting to see.” Mice that consumed regular kibble in fixed time periods also had less body fat than those that ate the same food whenever they chose.
Precisely how a time-based eating pattern staved off weight gain and illness is not fully understood, but Dr. Panda and his colleagues believe that the time at which food is eaten influences a body’s internal clock. “Meal times have more effect on circadian rhythm than dark and light cycles,” Dr. Panda says. And circadian rhythm in turn affects the function of many genes in the body that are known to involve metabolism.