Chubby Mice Show Why Midnight Snacking Makes Us Fat

Is midnight snacking bad for you? Diet experts have gone back and forth on that question, but new research from the University of Pennsylvania provides some dramatic evidence that chowing down late at night will indeed make you fat.

The study, published this week in the journal Nature Medicine, found that disrupting the body's internal clock can play a big role in weight gain. Or, to put it another way, it isn't so much what you eat as when you eat it that mucks up your metabolism.

The proof: Check out the chubby little fellow on the white surface in the accompanying photos, who was genetically altered so he would eat during the time he normally would have slept. Even though he and his altered buddies consumed the same number of calories as the unaltered, control mice (on the black surface), they still became obese little pudgeballs.

And should you think the weight gain was just because of the genetic manipulation, the researchers then caused obesity in the normal, unaltered mice by getting them to eat at the opposite time of their normal nocturnal noshing.

Researcher Georgios Paschos and his colleagues with the Perelman School of Medicine said that this behavioral change in the mice is similar to midnight snacking in humans. They explained that specialized "clock genes" in the hypothalamus of the brain regulate appetite during the day. When eating occurs at the wrong time - at night instead of day or vice versa - it upsets normal fat metabolism and leads to fat being stored instead of burned.

As Paschos explained in a press release, disrupting this inner clock can cause weight gain and metabolic problems in night shift workers and those with sleep disorders  - an increasing problem for older adults. Not getting enough sleep can also trigger weight gain for the same reason.

But here's the kicker: The researchers wrote that to their "amazement," they found they could restore normal metabolism in the mice by giving them supplements of two types of fatty acids - EPA and DHA - normally associated with fish oils. The oils play an important role in metabolizing fat, researchers said. Increasing the level of these unsaturated fatty acids in the bloodstream seemed to counteract the metabolic effects of altering the animals' natural eating and sleeping cycle.

Would this work for humans? Now there's a question for further research.

In other health news:

Cost becomes bigger question in treating heart disease. Reuters reports that the cost of treating heart disease has become a key factor in decisions by U.S. cardiologists grappling with the nation's No. 1 killer. Record prices for drugs and devices, reduced reimbursement by insurance plans and the looming full implementation of the health care reform law are convincing doctors to consider not only novel treatments, but also how to get the most bang for the buck.

Photo: Georgios Paschos PhD, Perelman School of Medicine, University of Pennsylvania.