Are Ex-Smokers Even More Likely to Gain Weight Than Previously Thought?


We’ve blogged several times here about the rise in American obesity and its various causes. From one of those earlier posts:

Why has the U.S. obesity rate risen so much? Many, many answers to this question have been offered, most of them having to do with changes in diet and lifestyle (and, to some degree, the changing definition of “obese”). There is an interesting paper by the economists Shin-Yi Chou, Michael Grossman, and Henry Saffer that sorts through many factors (including per capita number of restaurants, portion sizes and prices, etc.) and concludes — not surprisingly — that the spike in obesity mostly has to do with the widespread availability of very cheap, very tasty, very abundant food.

They also find that a widespread decline in cigarette smoking has helped drive the obesity rate. This seems very sensible, since nicotine is both a stimulant (which helps burn calories) and an appetite suppressant. But Jonathan Gruber and Michael Frakes have written a paper that calls into doubt whether a decrease in smoking indeed causes weight gain.

So does smoking less lead to weight gain or doesn’t it?

A new paper (gated) in the International Journal of Obesity argues that not only does smoking less lead to weight gain, but that the effects have to this date been underestimated — primarily because, as Michael Finke, one of the authors, explains, “smokers are not like nonsmokers.”

From the introduction of their paper:

Adult obesity rates in the United States have increased by more than 50 percent, whereas tobacco use among adults decreased by about 44 percent since 1970. There is strong evidence that smoking is inversely related to body mass index (B.M.I.).

However, smokers tend to consume diets that are higher in fat and lower in nutritional quality than nonsmokers. Smoking and unhealthy diet choice may reflect a preference for the present consumption. Smokers appear to exhibit a higher rate of time preference through myopic decision-making in multiple domains. If smokers are more present-oriented, and if activities such as healthy diet and exercise require placing a greater value on future well-being, it is possible that the past estimates of the relation between smoking and B.M.I. suffer from an omitted variable bias. This study attempts to correct this bias by including time preference through the use of a composite index of behaviors that reflect a preference for either future or present well-being.

This argument has a lot in common with several arguments we put forth in Freakonomics: that the kind of person more likely to do X is also more likely to do Y.

Humanists may find this unsettling: it is perhaps more comforting to think that our individual choices are, well, individual. But the empirical evidence continues to point in the other direction.


Here is an interesting question. How much weight gain would equate to the negative health effects of smoking 25 cigarettes per day? I know the measurement is arbitrary but economists love to measure things of this sort. I think years in reduced life expectancy would be reasonable. I think we can agree that they would probably have an equally poor quality of life.

Who would be a bigger burden (politically incorrect but true) on the health care system?


Interesting but doesn't apply to me. I've been a smoker for 15 yrs and when I quit smoking 2 yrs ago, I substituted exercise (running 5 days a wk)

and changed my diet. When I was smoking, I used to skip breakfast on a regular basis and would only eat lunch and dinner. Today I weigh 30 lbs less than when I was a smoker and have tons of energy at the end of the day.

Obviously the weight gain happens if one substitutes food (and a lot of it) for smoking because of the need for oral fixation. Also, as has been stated already, smokers tend to skip meals because smoking decreases the appetite and when one goes back to their pre smoking eating habits, they tend to gain weight.

For me it's not a choice between smoking and weight gain. Even if smoking raises the metabolism, the calories burned by smoking a cigarette can't be more than I'm already burning through regular exercise.


I have worked in addictions for 20 years and the clinical judgement gleaned from the scientific literature is that the average smoker who quits will gain 20 lbs on average but an individual would have to gain 75 lbs for the health risk to be equal. As you can see, one would have to eat themselves into morbid obesity to make health problems equivalent with smoking.


I have loved cigarettes since my late 20s, am now 54...I read and smoke and

drink beer to relax from the stress of being a single parent of a 14 year old just starting highschool. I eat well, I garden, I cook. The few times I tried to

"give it up" everything seemed to go out of whack. I often wonder, whether

something that gives one pleasure, is so bad, or is it those old Puritans coming back to haunt us.? Especially BAD women like myself...

Tilemahos Efthimiadis

Actually there is a more simple explanation. When a long time chain smokers quits (as I did 4 years ago) he/she regains the sense of taste and smell (these are repressed from the hot smoke in your mouth). It had been 15 years since I experienced how a rose smells.

Food is now more delicious and you desire to taste more as everything is new. This leads to over consumption. Also, you are more energetic and direct this energy to eating (if you were into exercise you wouldn't be smoking in the first place).

Jim Birch

4 (b) A nonsmoker who grows older and doesn’t cut calorie intake, or increase calorie consumption appropriately gains weight.


It is better to quit smoking and get FAT!... Why? well, for a smoker (varies in length of being a smoker of course), could get cancer, and other health problems, for himself AND, for others, the smoke which causes serverer (sometimes) dammage for innocent bystanders who do not merit of getting taht punishment. Whereas, by quitting smoking, would definately, not only make that smoker better off, but the others. In addition, as the effect of obesity is more apperent, so the "ex-smoker" can realize the growing problem quicker and therefore, take necessary actions, go to the docter etc., and fix this problem before too late; unlike the smokers with high risk of getting a cancer. Hence, i think quiting smoking is better for everybody. Of course, not starting to smoke in the first place is the best option.


1. Smoking "burns" off 200 calories per day by increases in basal metabolic rate.

2. As we age our metabolism and level of activity decline.

3. Age, sex and race-controlled active smokers weigh less than non-smokers across dietary and exercise variables.

4. A smoker who quits and doesn't cut calorie intake, or increase calorie consumption appropriately gains weight.

5. A lb. of body fat contains 3,500 calories.

6. In 17.5 days of non-smoking status-quo diet and exercise yields one pound of body fat.

7. Non-smokers can taste and smell food better, and their appetites pick up.

8. Sometimes one oral habit replaces another.

9. Regarding Gruber, et. al's study, they didn't control for black market cigarette consumption plus cigarettes purchased at Indian reservations. Also, the average age in their study was 44 and the average US age is 55, more or less.

The Commish

In regards to quiting --> getting fat --> getting heart disease: doesn't smoking contribute to heart disease as well?

Also, wouldn't you think of the weight gain in the same manner as an ex-athlete. Athletes eat well, but they also burn more calories during the day. So when an athlete retires/stops playing they can't just keep eating the same (even though they "eat well") because they aren't burning the same amount of calories. Therefore they have to adjust their caloric intake. The same would be true for a smoker, given they no longer have the nicotine to enhance their metabolism.

Point being - perhaps they are not compensating by eating more (and perhaps more unealthy foods), but just continuing to eat what they always have.

Also, do you think there is any correlation that quiters might be older in age and thus experiencing a decline in their metabolism regardless? I would think it a rarity that a teenager or young twentier quit and see a significant weight gain. I would also think those getting older would be more apt to pay attention to their lifestyle and thus more apt to quit.



It seems to me that quitting smoking slows your metabolism. Almost every former smoker I've ever known gained weight when they quit - sometimes a significant amount. At first I assumed that people were eating since they had an oral fixation and needed to fulfill it somehow. But my sister, who was always weight-conscious, quit smoking cold turkey when she got a lung infection that nearly killed her at 23. Within a few months she had gained 25 pounds, despite exercising more (it was easier when her lungs were healthy!) and eating the same amount. It seemed clear that her metabolism was slowed, at least temporarily. After two years, she was able to lose most of the weight.

On the other hand, I've seen plenty of massively obese smokers here in New York City. My favorite is when they have a donut in one hand and a cigarette in the other!


Smoking, such a mentioned problem nowadays, an addiction which has caused many deaths, both to the smokers, as well as non-smokers (second- hand smokers). People who decide to smoke must look at the marginal cost of this, probably you might get cancer, or suffer from other disease. The option value of others may be to quit smoking, which then most likely the person may become obese, or eat fatty foods, which also has a cost. But those who really examine the situation, may notice that if they are smokers and decide to quite they probably should have a healthy diet, and consult a nutrisionist if necessary. As I have learned, "the cost of something is waht you give up to get it."Therefore this depends on the person's value of things. It is their choice whether they start smoking, continue to smoke, or quit smoking.


Maybe the guy in the picture should stop eating so much bamba. Those osem snacks are filled with trans fats.

mike n

Even with a healthy diet while smoking and after quitting, 4 years now, its the additional quantity of "healthy food" that seems to be a problem with myself and others that I know. However, every doctor says better to gain weight and not smoke health wise. I wonder how true that really is?


To the just-quit doctor: you said your diet has always been "examplary" and you still gained 20 pounds after quitting smoking. But didn't the article JUST say that smoking suppresses appetite and also causes you to burn more calories? So even if you always ate well, now that you've quit, you're body is getting MORE food than it needs since you no longer have those two effects.


Also, to all the people talking about getting heart disease after quitting and then gaining weight, I seem to have just read that smoking is one of the leading causes of heart disease. If that is true, it's possible that the heart disease risk increase is just adding on to the risk already in place.


The difference between the first two papers linked are almost completely: different treatment of time - moving from quadratic to year and month dummies - and then using the cigarette tax instead of the price. I personally found the reasons for using the tax to be sketchy at best. I have to think about the time shift. My reaction, however, is that both studies are at best rough cuts. That is highlighted by the second study's notes that some of the results make little sense, which is of course a flashing light that we're not dead on in the analysis.

Feel Stupid

To sidetrack, what is this "CMS" that I keep seeing after all of these names on this blog?


I'm just a student, but I thought there might be a connection between weight gain after quitting smoking and Roy Baumeister's work on acts of self-restraint; his studies suggest that acts of self-restraint deplete blood glucose. (Not implausible, given how big a consumer of blood glucose the brain is and how much cognitive activity it takes to consider something rationally.) Nicotine is a powerful reinforcer, and acts of self-restraint in the context of addiction must verge on saint-like. Blood glucose goes down, hunger goes up--regardless of your actual fat stores. Not to mention that you're suddenly actually receiving more bodily feedback than before, since nicotine creates problems for acetylcholinergic neurons. Not only are you hungry, but you feel it more.

I have no idea if there are any gaping holes in this. Still, the finding does have something to say to dieters--the less you eat, the lower your blood sugar, the lower your ability to restrain yourself, the more likely you are to eat. How cruel.


M Todd

According the the figures (Dr. Richard Doll study) to determine lung cancer and smoking, 7 in 100,000 non smokers will contract lung cancer and 160 in 100,000 smokers will contract lung cancer which is a 2400% change greater than non smokers.

That sounds impressive, but statistically that means that if you smoke you run a 99.84% chance of NOT getting cancer. Plus, the majority (70%) who do develop lung cancer do so in their 70s and 80s. Also, all smokers are lumped together with little distinction between the person who smoke 1/2 pack a day and 2 packs a day. If you smoked more than 100 cigarettes in your life and die of lung cancer you will be included with the 160 smokers.

I am not endorsing smoking, but while the health risks of smoking have been amplified... being overweight has been minimized in this country.

Most of my friends do not smoke, but some eat way to much fat and sugar and are over weight yet consider themselves healthier than a smoker with the proper weight. Fact is they are no better off or actually could be worse off considering heart and diabetes will claim more lives than lung cancer.

Anything extreme is unhealthy. I think moderation is the key to a healthier life. Eat, drink, and if you smoke do so in moderation. Someone who watches their fats and sugars, gets moderate exercise, and smokes less than 10 cigarettes per day will be healthier than a non-smoker who does not eat properly and watches TV all night.



Smokers have a very serious decision that could change their lives. Smoking has been proved to be very unhealthy, causing serious health problems, like cancer, but as being proved in this article, to quit smoking also brings negative consequences to a person's health. If people quit smoking, they are faced with higher chances of obesity. Obesity also brings health issues, such as PelayoCMS said, "a heart problem." So what should smokers do, quit smoking and face obesity or continue smoking and face cancer. The decision is very tough, but as well as with any other decision, one must see what the pros and the cons are and based on this, make a decision.

For those who are not smokers yet, the best decision to take is to never start. Now the problem is not quitting, but the fact that if people quit, they are more likely to become obese. So either way, if you continue smoking or if you quit, you are more likely to have health problems than if you never started to smoke.