Scientists: We Know Why Smoking Keeps Your Weight Down

| Thu Jun. 9, 2011 7:00 PM EDT

If you're one of the many smokers who cites "weight gain" as a reason not to quit (publically, or to yourself when no one can hear you), this one's for you. Researchers at Yale are publishing a study in the June 10, 2011 issue of Science journal that outlines a new discovery they made through trial by mouse: the dirty details on how smoking suppresses appetite. Their findings may pave the way to development of a drug that will prevent the notorious cigarette-free gain (about ten pounds on average). Here's a breakdown of the research:

Why smoking makes you eat less: Our devilish friend nicotine travels to the brain and hooks up with neurons in the hypothalamus, which houses the brain function that controls feeding. The message it sends to receptors there reduces food intake, and voila, smokers are skinnier. Meanwhile, nicotine has a dark downside—it latches onto other cerebral receptors, making you crave tobacco. But that we knew.

How the researchers figured this out: In the study, mice were given a nicotine-like drug called cytisine—it made them eat less and cut down their body fat. Then, when the mice took a drug that prevented the cytisine from binding to its hypothalamic receptors, the reduction in food intake was reversed.

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What researchers hope to do about it: The crew at Yale, led by Dr. Marina Picciotto, would like to develop a drug that activates that appetite suppressing receptor without nicotine use, so folks can quit smoking and stay at their desired body mass. Picciotto hopes it might help with weight issues unrelated to smoking as well.

"Many people say they won't quit smoking because they'll gain weight," said Picciotto in a press release. "Ultimately, we would like to help people maintain their body weight when they kick the habit and perhaps help non-smokers who are struggling with obesity."

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