Introduction

Choosing to quit smoking is often one of the most challenging yet transformative steps a person can take to improve their health. But doing so can significantly reduce a person's risk of cancer, heart disease, and respiratory illnesses. However, a common concern among those trying to quit is the potential for weight gain. Many people experience weight gain after quitting, and in some cases, the increase can be so rapid that it discourages them from staying smoke-free. This article will explore the link between nicotine withdrawal and weight gain, offering clear, evidence-based strategies individuals can use to help minimise the risk of gaining weight.

Understanding nicotine withdrawal

Tobacco products contain nicotine, which is the main addictive component. It has a significant influence over multiple neurotransmitter networks within the brain. In particular, it can regulate the levels of dopamine, serotonin, and norepinephrine. These affect mood, attention span, as well as the regulation of appetite. In the event that the body is suddenly deprived of nicotine, the brain experiences a drop in these neurotransmitters, leading to what is commonly known as "nicotine withdrawal".

Symptoms of withdrawal from smoking usually begin within a few hours of the last cigarette. There is a peak in symptoms at around 2-3 days, which could last for a few weeks. The main symptoms are anxiety, irritability, difficulty in maintaining concentration, and insomnia, with an increase in appetite for food.¹

Why does weight gain happen after quitting smoking?

It is well-documented that weight gain can occur as a side effect of smoking withdrawal. In fact, on average, individuals can gain 4-5 kg within the first year of quitting smoking,^{1, 2} The reasons for this can vary:

Increased appetite

Nicotine possesses appetite-suppressing properties, which means that when an individual stops using it, their appetite tends to increase. This is due to the body's attempt to stabilise levels of neurotransmitters as well as changes in hormone regulation that are related to satiety.²

Slower metabolism

The body's basal metabolic rate (BMR) is increased when nicotine is introduced into the system. This means that nicotine will help the body burn more calories. Once nicotine is no longer present in the system, the BMR will decrease, thereby reducing the overall calories burned. The decline in metabolism contributes to the gradual accumulation of excess body weight, which is even more apparent if calorie intake is not adjusted accordingly.³

Improved taste and smell

Smoking dulls the taste buds and olfactory receptors. Once these senses begin to recover, food may seem more flavourful, leading individuals to eat more frequently or choose richer, more calorie-dense foods.⁴

Emotional or habitual eating

Smoking can be a tool that people use in response to stress or boredom. Therefore, after quitting smoking, food—especially snacks high in sugar or fat—can become a substitute for cigarettes. Eating becomes a coping mechanism for dealing with the discomfort of withdrawal or the absence of habitual hand-to-mouth behaviour.⁵

Does everyone gain weight after quitting smoking?

Not necessarily. While weight gain may be a common symptom among those who are trying to quit smoking, it is by no means inevitable. A recent study that looked at over 20,000 adults found that almost 16% of smokers who quit did not gain any weight, and about 13% even lost weight.² There are various factors, such as age, sex, socioeconomic status, dietary habits, and levels of physical activity, that play a significant role in a person's susceptibility to gaining weight. It is important to note that the respiratory and cardiovascular benefits of quitting smoking far exceed the risks associated with moderate weight gain. Former smokers who gain weight significantly reduce their risk of premature death and chronic disease compared to those who continue smoking.^{4, 6}

Strategies to prevent or minimise weight gain

It might appear that weight gain will be difficult to avoid while you try to quit smoking; however,  several effective, evidence-based strategies can reduce or even prevent weight gain while quitting smoking.

Nicotine replacement therapy (NRT)

Usually, the first line of treatment for individuals seeking to quit smoking is NRT. Products such as nicotine patches, lozenges, gum, and nasal sprays can help with the unpleasant withdrawal symptoms. But they can also reduce food cravings by stabilising dopamine levels in the brain. There have even been studies that have demonstrated that people who use NRT are less likely to gain weight in the early stages of quitting compared to those who quit “cold turkey.”.⁷

Medications

Prescription medications that have been used traditionally to aid in smoking cessation, such as bupropion, have been shown to significantly help in limiting post-cessation weight gain, particularly when used short-term. Varenicline, which is another medication used in smoking cessation therapy, is effective at reducing cravings and other withdrawal symptoms.⁸

Behavioural support and counselling

There are various non-medication therapies, such as motivational interviewing and cognitive-behavioural therapy (CBT), that can help individuals identify emotional eating and triggers. These programs are often centred around nutritional education, meal planning, and mindful eating strategies.⁹

Mindful eating practices

An awareness of why, when, and how you eat can transform your outlook on food. Mindful eating aims to encourage people to use various techniques such as slowing down during mealtimes, recognising hunger cues, and avoiding using food as a response to boredom or stressful moments. Studies have shown that individuals who practised mindful eating during smoking cessation periods are more likely to manage their weight gain effectively.⁹

Physical activity

One of the most important tools in managing post-cessation weight gain is exercise. Physical activity boosts metabolism, improves mood, reduces stress, and distracts from cigarette cravings. Regular aerobic activity, such as walking, cycling, and swimming, helps to maintain lean muscle mass, which supports a healthy metabolic rate. While resistance training using weights can further enhance the metabolic benefits of exercising,^{6, 10} even taking a short daily walk has been shown to help manage weight and stabilise mood in those trying to quit smoking.

Choose healthy snacks

Keeping low-calorie snacks accessible to you can help with impulsive eating. Pre-cut fruits, raw vegetables, unsalted nuts, or even air-popped popcorn can help you avoid substituting cigarettes with sugary drinks and processed snacks. The latter can cause rapid weight gain and blood sugar spikes.

Drink plenty of water

A key component of metabolic function is hydration. Therefore, it is important to maintain hydration, particularly as the sensation of thirst is often mistaken for hunger. Maintaining a good practice of hydration throughout the day may help reduce unnecessary snacking.

Track your progress

Accountability is also a great tool for keeping yourself on track during your quitting journey. Using a food diary or fitness app can help you track what you eat and how often you exercise. This can provide valuable insights and motivation while you identify patterns, such as behavioural eating habits. You can use the information to adopt new behavioural changes that can help you limit weight gain.

Set realistic goals

It is important to set realistic goals and to be comfortable with the fact that some initial weight gain may occur, which is normal and expected. The primary goal of quitting smoking should always be kept in mind, while weight concerns can then be addressed over time. Adopting a gradual and sustainable approach is more effective than extreme diets or tough restrictions, which can cause the individual to relapse.

Summary

Individuals who are on their quitting journey may be wary of gaining weight, something which may stop them from even attempting to quit. But it is important to understand that post-cessation weight gain is manageable—and in most cases, temporary—particularly if the right tools and support are used. There is an overwhelming benefit to quitting smoking, from improvements in cardiovascular health to respiratory function, which far exceed the high risks associated with gaining a small amount of weight.

It is possible to quit smoking without gaining any significant weight by combining nicotine replacement therapy, behavioural strategies, healthy eating habits, and regular physical activity. If you are planning on quitting or are currently in the process, speaking to your healthcare provider will give you the personalised support and strategies that will reduce your likelihood of gaining weight while ditching the nicotine.