Circadian rhythm ups cravings for sweet, starchy, salty snacks

PORTLAND, Ore., May 11 (UPI) -- The body's circadian rhythm increases hunger and cravings for sweet, starchy and salty foods in the evening, which helps pack on pounds, U.S. researchers say.

Senior author Steven Shea, director for the Center for Research on Occupational and Environmental Toxicology at Oregon Health & Science University, said the urge to consume more in the evening may have helped our ancestors store energy to survive longer in times of food scarcity, but in a world of high-calorie late night snacks might result in significant weight gain.

"Of course, there are many factors that affect weight gain, principally diet and exercise, but the time of eating also has an effect. We found with this study that the internal circadian system also likely plays a role in today's obesity epidemic because it intensifies hunger at night," Shea said in a statement. "People who eat a lot in the evening, especially high-calorie foods and beverages, are more likely to be overweight or obese."

Indeed, eating a lot in the evening can be counterproductive since the human body handles nutrients differently depending on the time of day. For example, sugar tolerance is impaired in the evening. Additionally, consuming more calories in the evening predisposes people to more energy storage; we simply don't expend as much energy after an evening meal in comparison to morning meals, the researchers said.

The findings were published in the journal Obesity.