Why Cessation of Smoking Leads to Fat Gain

Many of the threads recently about smoking have driven me to post on this subject...

Smoking cigarettes, through its effects on the cardiovascular system, is the most preventable cause of premature death in the United States (1). But who wants to quit if the positive health effects are accompanied by negative physical attributes. We all know someone who quit smoking and subsequently ballooned quicker than Oprah did after failed Dr. Oz Diet #48. Some experts estimate that 1 out of 4 quitters gain weight and yet others estimate 1 out of 2. Scouring the internet I found the general consensus regarding average weight gain upon cessation to be between 5-10 pounds, most of which is undoubtedly fat. About.com sums up the "why"

•Smoking burns up to 200 calories a day in a heavy smoker

•Because smoking burns calories, metabolism is boosted (increased) slightly

•Nicotine is an appetite suppressant

Essentially, we're told by most experts 1 of 2 things: to believe that smoking cessation leads to a surplus of calories, due to the negative stimulus of nicotine, that, over time, leads to increased fat depostition. Using this logic; or to believe that quitters replace smoking with food, consuming more calories and, from a surplus of calories, get fat. However, both of these explanations fail to address the true cause at hand.

I personally know family members and friends (and stories from Professionals) that have replaced smoking with sugar-free gum-chewing without altering caloric intake and still got fat, an anecdote (observed by countless others) which kinda throws the latter explanation out the door.

The former is quite a bit more difficult to dismantle, as it does make a few factual points. Nicotine can indirectly cause a decrease in appetite (less caloric intake). And smokers tend to burn more calories than recent quitters. However, caloric surplus/deficit has little effect on fat deposition/mobilization over the course of days, especially small net differences (as I pointed out here). It would seem that these observations are caused by another factor...

Lipoprotein Lipase(LPL) is an enzyme that hydrolizes triglycerides found in VLDL so that they may pass through the cellular wall in muscle cells for fuel and in fat cells for storage. So, LPL activity on fat cells leads to fat deposition and LPL activity on muscle cells leads to fat oxidation (fat used as energy). What's interesting is the effects that nicotine has on LPL activity on respective sites:

Alterations of lipolysis and lipoprotein lipase in chronically nicotine-treated rats

These studies examined the cellular mechanisms for lower adiposity seen with nicotine ingestion. Rats were infused with nicotine or saline for 1 wk and adipocytes isolated from epididymal fat pads. Nicotine-infused rats gained 37% less weight and had 21% smaller fat pads. Basal lipolysis was 78% higher, whereas the maximal lipolytic response to isoproterenol was blunted in adipocytes from nicotine-infused rats. The antilipolytic actions of adenosine and the levels of serum catecholamines were unaffected by nicotine. The nicotine-induced alteration in lipolysis was not associated with any changes in hormone-sensitive lipase. Nicotine caused a 30% decrease in lipoprotein lipase (LPL) activity, without any changes in LPL mass or mRNA levels, in epididymal fat in the fed state. In contrast, LPL activity, mass, and mRNA levels in heart were increased by nicotine whether animals were fed or fasted.

These studies provide evidence for multiple mechanistic events underlying nicotine-induced alterations in weight and suggest that nicotine diverts fat storage away from adipose tissue and toward utilization by muscle.

In easier terms, this study shows that nicotine increases LPL activity on skeletal muscles and the heart muscle at rest (causing more calories to be burned) and decreases LPL activity on fat cells (which means less fat was being deposited in fat cells). The nicotine induced rats had less fat accumulation than the saline group.

The effect of acute and chronic administration of nicotine on lipoprotein lipase activity

Nicotine was injected intraperitoneally to rats and 2 h later lipoprotein lipase was determined in isolated perfused hearts. There was a significant increase in heparin releasable lipoprotein lipase activity which represents the functional pool without increase in total enzyme activity. When 1 microliter/h of a solution of nicotine (120 mg/ml) was delivered for 3 days from subcutaneously implanted miniosmotic pumps, total lipoprotein lipase activity in the heart increased 1.5-3.0 fold. Endogenous lipoprotein lipase activity in plasma doubled and there was a significant fall in plasma triglyceride levels. The effect of nicotine on heart lipoprotein lipase activity was evident also after 6 days of continuous delivery and was accompanied by a fall in adipose tissue lipoprotein lipase activity. No effect was seen when the dose of nicotine was halved. A positive correlation was seen between plasma nicotine levels and heart lipoprotein lipase activity, while adipose tissue lipoprotein lipase correlated negatively with plasma nicotine levels. Chronic administration of nicotine was accompanied by either weight loss or diminished weight gain. It is concluded that in the rat the acute effect of nicotine on the shift of lipoprotein lipase to the functional pool could be related to enhanced beta-adrenergic stimulation. The chronic effect of nicotine could have been mediated by the loss in body weight, due to reduced caloric intake.

This is simply another study demonstrating the same effects of the aforementioned. Nicotine correlates positively with LPL activity on muscle cells and inversely on fat cells.

Don't like rat studies? Ok....

Smoking depresses adipose lipoprotein lipase response to oral glucose

Adipose tissue lipoprotein lipase was studied in smokers (n= 17) aged 18–47 years and compared with enzyme activity in non-smokers of comparable age (n= 8) and a second time in some of the subjects 5–9 weeks after cessation of smoking (n= 7). Serum cotinine levels served to validate the smoking status of the subjects. Fasting enzyme activity was similar in smokers and non-smokers, when expressed per 106 cells, but was significantly increased when normalized for cell size. When lipoprotein lipase was determined in the same individual 4 h after an oral glucose load, a significant decrease (P< 0.002) occurred in the smokers, while enzyme activity rose in the non-smokers (P

Cool a positive side to smoking other than killing myself slowly..
Now i wont look half as insane when i just say the 1st one..

And yes I love smoking for the reason stated above..

reply to post by ThichHeaded


There ya go...keep it positive.

...i dont believe that smoking cigarettes is the most preventable cause of premature death in the usofa... i think auto accidents are...

...worldwide, i'd say poverty and war are the most preventable causes of premature deaths...

...really interesting stuff you posted though... give up carbs, huh?... does that include beer?... if it does, its an evil conspiracy...


...a lot of people stop smoking when they get older and thats when many start putting on pounds anyways because you're not as active as you used to be, especially in the sack and thats where calorie burn off is the most effective...

...i didnt smoke during the 70s because i was pregnant... sigh, good times, the decade when everything made me throw up (except sex)...

...maybe nervousness causes folks to eat more when they stop smoking... they dont know what to do with their hands and, then, theres that oral need... sucking on a drinking straw helps if you can convince yourself that it does...

Originally posted by Wyn Hawks
...really interesting stuff you posted though... give up carbs, huh?... does that include beer?... if it does, its an evil conspiracy...

That doesn't mean "give up carbs". It just means if you're quitting smoking then you need to restrict your carb intake to compensate for the negative stimulus of nicotine.

...maybe nervousness causes folks to eat more when they stop smoking... they dont know what to do with their hands and, then, theres that oral need... sucking on a drinking straw helps if you can convince yourself that it does...

But people are getting fatter independently of caloric intake.

There certainly are a massive amount of fat people who smoke regularly! God forbid if they should try to quit.

I smoked for 25 years of my life, I was a complete addict to nicotine and could barely function without cigarettes. If I tried to quit (which I tried for 25 years) I would literally lose the ability to articulate words. My metabolism was through the roof and I was a buzz with thoughts and ideas as a smoker.

I quit 4 years ago and I immediately "crashed", physically and emotionally; I went from 170 pounds to a whopping 220 pounds. It was an experience to see such an increase and to have to invest in all new clothing. I have since given all of those fat clothes away. I am now at 180 pounds and I feel terrific. I feel that my metabolism is finally getting back to my "hyper" self again, and now I recognize the true levels of "anxiety" that I have held throughout my life. All those years I was having anxiety attacks not nicotine fits LOL, I was such a drama queen!

I do grow tobacco but I don't smoke it. I am currently under the belief that Tobacco will be like money in the future. I am not worried about people becoming addicted by obtaining my tobacco from me because I do not believe that "home-grown" and "chemically saturated" tobacco is the same at all.

There is no doubt that Tobacco is a poisonous plant, but it is the refinement by way of fermentation that enables people to enjoy its wonderful effects without the bad elements; another thing that Industry has taken from us, Nature's tobacco!

I am all for anyone quitting and I am an Advocate for even Medicinal intervention in helping those overcome Modern Cigarettes, but I also do not mind someone smoking near me if it is a natural blend because the aromas are completely different.

Interesting OP, S&F

reply to post by Greensage


I should have been clearer. It shouldn't be taken that all smokers are skinny. Rather that nicotine positively affects fat metabolism.