A study suggests that a nighttime fast may help cut the risk of weight gain and the diseases that come with it.
In an age of long commutes, late sports practices, endless workdays and 24/7 TV programming, the image of a parent declaring "the kitchen is closed" at 7 p.m. seems a quaint relic of an earlier era. It also harks back to a thinner America. And that may be no coincidence.
A new study, conducted on mice, hints at an unexpected contributor to the nation's epidemic of obesity -- and, if human studies bear it out, a possible way to have our cake and eat it too, with less risk of weight gain and the diseases that come with it. Just eat your cake -- or better yet, an apple -- earlier. Then wait 16 hours, until breakfast to eat again.
"We have to come up with something that is a simple alternative to calorie counting," said Satchidananda Panda, a regulatory biologist at the Salk Institute in La Jolla, Calif., who led the study published online by the journal Cell Metabolism.
Panda and his team put groups of mice on different eating regimens for 100 days. Two groups dined on high-fat, high-calorie chow while a control group ate regular food. Half of the high-fat eaters ate whenever they wanted, nibbling on and off throughout the night and day. The other high-calorie group had access to food only for eight hours at night, when they were most active.
In human terms, this would be rough: No ice cream while watching "Glee." Not even a late-night glass of warm milk.
The difference was astonishing. Even though they ate a high-fat diet, the mice who wrapped up their eating day early and were forced to fast for 16 hours were lean -- almost as lean as mice in a control group. But the mice who noshed around the clock became obese, even though they consumed the same amount of fat and calories as the time-restricted eaters.
The obese mice also developed high cholesterol, high blood sugar, fatty liver disease and metabolic problems. The mice who ate fatty food but were forced to fast showed hardly any signs of inflammation or liver disease, and their cholesterol and blood sugar levels were virtually indistinguishable from those of mice who ate regular chow. When put on an exercise wheel, they showed the most endurance and the best motor control of all the animals.
The data suggest that the stomach, the brain and the body's digestive machinery need to take a break from managing incoming fuel; otherwise, we may be working ourselves into a state of metabolic exhaustion. When combined with high-calorie, high-fat diets, the result is weight gain, a liver clogged with fat, accumulation of cholesterol in the arteries and unused glucose in the blood.
The study drew cautious interest from obesity researchers, who underscored that lab mice aren't tempted by fast-food restaurants with late-night specials. "I hope it's true, but I doubt it," said Barbara Corkey, director of obesity research at Boston University School of Medicine.
Panda acknowledged that his research would need to be refined. But extending the nighttime fast is a cheap and simple dietary adjustment that doesn't require anyone to count calories or even deprive themselves. All you need is a clock, he said.