Why can quitting smoking lead to weight gain?
Weight gain following smoking cessation is a reality. On average and after one year, a former smoker will have gained between 2 and 5.5 kg, between 4 and 5 kg after 10 years(1). But weight gain remains highly variable depending on the individual: about a third of ex-smokers maintain a stable weight, while about 15% of them lose weight. How to explain such weight fluctuations when you quit smoking? Do we inevitably get fat when quitting smoking or are there ways to keep weight control?
The weight of the smoker
The majority of epidemiological studies indicate that smokers are statistically underweight than non-smokers. This “underweight” is explained, among other things, by the intrinsic properties of nicotine present in tobacco.
- Nicotine decreases appetite, size and frequency of food intake, as it has a direct impact on the hypothalamus, the center ofhungercontrol andsatiety. It has a satietogenic (“appetite suppressant”) effect, as it increases sensitivity toleptin, the satiety hormone. The obvious impact is a decrease in BMIin smokers(2).
- It also has the effect of increasing energy expenditure, both at rest and duringphysical activity(3). This phenomenon is not yet perfectly explained scientifically, but could be caused by a catecholaminergic effect (catecholamines involved in the glycogen metabolism balance), leading to greater thermogenesis.
- Finally, nicotine inhibits mono-amine oxidase in charge of destroying part of serotonin. The brain, in “overflow” of serotonin, is in a state of well-being. Thus, smokers have less appetite for sugar and a lower propensity for food “urges”.
But nicotine alone does not explain the lower BMI of smokers.
- The pleasure of eating orally is replaced by the act of smoking (bringing a cigarette, a cigar to your mouth…).
- Smoking leads to a degradation of taste, smell and palatability. Thus, the act of eating brings less pleasure and satisfaction to a smoker than to a non-smoker.
Weight gain when quitting smoking
So what happens when you quit smoking? Weight gain is driven by a set of mechanisms, listed in the diagram below
Thus, quitting smoking clearly leads to a change in behavior and eating habits. It is explained by:
- Food compensation for the loss of orality. We put food in our mouths rather than a cigarette…
- The rediscovery of the pleasure of eating – the ex-smoker gradually regains a finer perception of the flavors of food, so much so that he is more tempted to eat. In addition, he recovers his sense of smell, so that certain food odors, hitherto imperceptible, can arouse in him an increased appetite and desire to eat.
- The “deficiency” in nicotine mechanically leads to a cerebral deficit of serotonin. This deficit then causes a greater propensity tosnack bar , especially sweet.
- The withdrawal phenomenon, since nicotine is addictive, can lead to increased stresstag. The brain will try to compensate with other substances that activate the reward circuit, such as tobacco nicotine. This is the case, for example, with fatty foods (triglycerides act on dopaminergic circuits), but also withSugar (5)
- Quitting smoking causes less (temporary) sensitivity to leptin. Thus, former smokers tend to be full less quickly. Food intake is therefore often greater, both in quantity and frequency, during smoking cessation.
- In general, we observe in smokers a less good general lifestyle: less physical activity (among other things due to low cardiovascular capacity), but also less good basic eating habits (smokers eat less fruit and vegetables , fibers, whole grains or dairy products than non-smokers (6)). Thus, this poor lifestyle would have a direct impact on weight, after smoking.
- Finally, the energy expenditure induced by smoking (between 200 and 300 kcal per day, depending on daily tobacco consumption) is suppressed. Automatically, the calories burned before are no longer burned, and we are thus more inclined to gain weight.
How to avoid gaining weight when quitting smoking?
Beforehand, it is necessary to make two reminders:
- Moderate weight gain is not dramatic, especially when considering the harm caused by tobacco – cardiovascular disease, respiratory disorders, Allergies, asthma, digestive diseases, cancer….
- Quite often, the smoker is in fact below the weight that would naturally be his, if he did not smoke. Also, when you quit smoking, the weight gain would only be the “catch-up” of the lost weight.
Then, we will provide recommendations related to:
- When quitting smoking, increased physical activity is a must. It is essential to play sports, both to increase energy expenditure (including at rest, thanks to the development of muscle mass) and to overcome the phenomenon of lack and the stress that follows.
- From a food point of view, it is advisable to consume satiating foods. Fruits, vegetables and whole grains, rich inFiber, help to quickly reach satiety. In addition,Protein (preferably lean), long to digest, are effective in achieving lasting satiation.
- Food cravings, common when quitting smoking, should be satisfied with a healthy snack with ” appetite suppressant ” properties: quarkHard-boiled egg , fruit (such as an ApplegoldBanana ), a handful of oilseeds, etc.
- Dietary restriction is not recommended. Quitting smoking is already, in itself, a source of stress. Imposing astrict diet on an individual in full weaning risks having a counter-productive effect: not only will the success of the weaning be compromised but in addition, there is a risk of further disturbing a Metabolism which is already so.
- A possible nicotine supplementation via nicotine substitutes (gums, patch, spray) prescribed by the attending physician, can facilitate complete withdrawal and, in addition, avoid excessive and/or sudden weight gain.
Stephen Paul is the lead author and founder of My Health Sponsor. Holder of a diploma in health and well-being coaching with more than 200 articles in the field of health, he makes it a point of honor to offer advice based on reliable information, based on scientific research, and verified by health professionals.