In clinical setting, weight gain after quitting smoking is a complain that many patients have.
Which evidence do we have and what's the reccomended approach to treat this condition?
The literature regarding smoking cessation and weight gain is abundant and probably I won’t be able to go through all the points in my post.
Some years ago, a paper published in Obesity Reviews by Fizolof et al (Obes Rev. 2004 May;5(2):95-103) provided a excellent overview on the topic. As it is not open access, here are some interesting extracts which should bring some clarifications
First, regarding the evidence for weight gain smoking cessation:
Whereas numerous studies have found evidence that smoking cessation is associated with weight gain, there is controversy regarding the consistency and magnitude of this weight gain. Although most will gain less than 4.5 kg, as many as 13% of quitters may gain at least 11 kg. African Americans, people under the age of 55 and heavy smokers (those smoking more than 25 cigarettes per day) are at elevated risk for major weight gain. Besides, low socio-economic status was also associated to higher weight gain.
However, studies often showed some methodological limitations such as
the use of self-reported height and weight, failure to biochemically validate smoking status, a tendency to report point prevalence vs. continuous abstinence and limited follow-up periods.
What are the possible mechanisms associated with weight gain?
The mechanism of weight gain include increased energy intake, decreased resting metabolic rate, decreased physical activ- ity, and changes in adipose tissue-lipoprotein lipase (AT-LPL) activity and lipolysis.
There is no clear evidence based recommendations to avoid weight gain after smoking (probably due to the lack of a clear consensus regarding weight gain and smoking cessation).
Filozof reviewed some studies which investigated either pharmacological or behavioural/diet interventions in smoking cessation:
Nicotine replacement – in particular nicotine gum – appears to be effective in delaying post-cessation weight gain (1). However, once nicotine gum use ceases, the quitting smoker gains an amount of weight that is about the same as if she or he had never used gum (1).
1 mg of nicotine (contained in a chewing gum) has a pronounced thermogenic effect that could be increased by 100% by adding 100 mg caffeine (2).
Assali et al. reported no prevention of weight gain by transdermal nicotine replacement patch (3)
Compared with placebo, mean body weight gain at the end of treatment was significantly lower in patients receiving short-term bupropion 300 mg d-1 who had been continuously abstinent (4), long-term bupropion (5) or bupropion plus nicotine patch (5)
Danielsson et al. (5) reported higher rates of success for smoking cessation by combining the smoking cessation programme with an intervention diet.
Some studies (7,8) reported that exercise might minimize weight gain after smoking cessation.
Sources (did not manage to format the list better...)