Many smokers believe that kicking the habit goes hand in hand with subsequent weight gain.
Now, scientific evidence appears to support the claim and provide a possible reason. Ex-smokers may need to increase their physical activity levels in order to use the same number of calories once burned during smoking, the research team suggests. In a study of 10 men, the researchers evaluated the effects of smoking on energy expenditures during rest and while riding stationary bicycles at a moderate pace. But when the investigators took into account the smokers' nicotine levels, the increase in energy expenditure no longer differed significantly according to whether smoking was done at rest or while active. The authors note several important limitations of the study.