Scientists Pinpoint Why Smokers Pack on Pounds When They Quit

By Valerie Ross | June 10, 2011 1:04 pm

What’s the News: Scientists—and smokers—have long known that nicotine is an appetite suppressant, but just how it kept hunger at bay remained unclear. Now, researchers have uncovered the neural pathway by which nicotine reduces appetite, in a study published today in Science. This discovery could lead to new drugs that help people quit smoking or lose weight.

How the Heck:

  • The researchers first observed that mice given nicotine or the drug cytisine, which binds to some nicotinic receptors in the brain, ate less and had less body fat than mice not given either drug. When the researchers gave mice a chemical compound that blocked nicotine receptors, the appetite-suppressing effects of these drugs went away.
  • Since cytisine binds particularly well to a type of nicotinic receptor called α3β4, the researchers figured that receptor might be the major player in decreasing appetite. Sure enough, when the researchers genetically knocked out that receptor in some mice, those mice were immune to the drugs’ appetite-reducing effects.
  • The researchers then looked at what parts of the brain had α3β4 receptors, since different nicotinic receptors are present in different groups of neurons. These particular receptors show up in POMC cells, they found. This makes sense, given POMC cells are clustered in the hypothalamus—an area of the brain that plays a role in controlling lots of basic functions, including appetite.

What’s the Context:

  • Since smoking tamps down appetite, many smokers gain weight when they stop—a common reason people hesitate to quit.
  • Importantly, these results show that nicotine causes a dip in appetite by a different pathway than it triggers addiction. This means that it’s possible to make a drug that isn’t addictive, but still has nicotine’s appetite-suppressing powers.
  • Drugs that work on this POMC pathway could help smokers keep the weight off when they give up cigarettes, encouraging them to quit, and also be used to help non-smokers struggling with their weight.

Reference: Yann S. Mineur et al. “Nicotine Decreases Food Intake Through Activation of POMC Neurons.” Science, June 10, 2011. DOI:10.1126/science.1201889

Image: Flickr / julianrod

CATEGORIZED UNDER: Health & Medicine, Mind & Brain
  • Iowa

    Massive decline in smoking. Massive increase in obesity (though I know it doesn’t make much sense with spoiled children.)

  • John Lerch

    It’s not the addiction per se that’s bad–it’s the CV side affects.

  • Ajoykumar U.V.

    When I stopped smoking I felt the food items tastier than before. I noticed this several times. (Stopped and started many times!!). There may be a correlation between the taste buds in tongue and nicotine.

    This should also be taken into context.

  • JustMe

    When you quit smoking, your nasal passages are cleared up. Thus, you can smell things better which is directly linked to tasting things better.

  • Carole Aus

    Sixteen years ago I quit smoking for a full year; hated every minute of it. Started gaining weight. Taste and smell remained the same with or without cigarettes. Went back to the smokes after that year; still smoke. STILL GAINING WEIGHT!!!!!!!!!!??????????? Diets and exercise haven’t worked. Could it just be age? I’m 74.

  • The Blue Collar Man

    In 2009, I stopped smoking store bought cigs. Did it to save money. Bought the easy to use “Injector” machine, to stuff tobacco into to empty cig shells, with filter already attached. The Tobacco is NOT sent out to have it heavily laced with chemicals, but is “natural”.
    I was surprised. I saved lots of money after start up, about $25 for 2 weeks of cancer inhancing but DRUG FREE smoking.
    My health wasn’t an issue before, but my mental health improved dramatically!! Something in the store bought cigs had been posioning me for years, but I didn’;t know it!
    With natural Tobacco, in 2 weeks, the chemicals were gone, and I experienced a natural “high”, almost every day. My confidence level was normally good, but increased. I lost about 10 pounds without doing anything. The “must have a cig right now, no matter what”, has decreased dramatically. I was a 1 1/2-1 3/4 pack a day smoker. Some days I only smoke 18 cigs, as the severe drive to smoke is gone. Now, I can’t chain smoke like I used to, as it’s not tasteful, and is annoying. If i get in a place where it’s impossible to smoke, I can now withstand the urge for quite a while. I’m going on 71, and feel my total health is the best it’s been since my 40’s.


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