How does smoking affect your weight?

Smoking and consuming nicotine can affect your blood sugar and impact your appetite.
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How does smoking affect your weight

Smoking impacts on how your body functions as a whole. It increases carbon monoxide in your body, which decreases oxygen levels. Smoking can speed up and put pressure on your heart and it also slows down circulation due to your blood becoming thicker.

Nicotine, the highly addictive substance in tobacco and vaping products, is a psychoactive substance. This means it affects how the brain works, as well as your body. Nicotine releases stress hormones in the body and triggers your ‘fight or flight’ response. This affects your appetite in different ways, which in turn can affect your weight.

How smoking affects your weight

Smoking is linked with both weight loss and weight gain. Studies show that long term and heavy smokers are more likely to be overweight or obese than those who don’t smoke.


Nicotine causes your body to release cortisol, your main stress hormone. Cortisol is used in your ‘fight or flight’ response to danger. It shuts down systems in your body such as your digestive system and immune system. It does this to preserve energy for either facing or running away from a threat.

If there is no threat, people might experience:

  • Anxious feelings
  • Restlessness
  • An inability to focus
  • Temporary loss of appetite

Blood sugar levels

Your body releases cortisol when you smoke. Cortisol stimulates gluconeogenesis, meaning it makes your body form glucose. Glucose is a sugar and your body breaks food down into glucose for energy. So, when you experience a spike in cortisol you will also experience a spike in sugar.

Your body responds to a spike in sugar by increasing insulin to break down the sugar. This can leave you with low blood sugar levels. People often crave sugary foods and drinks when they experience low blood sugar. Sugary foods will cause blood sugar to spike again and start the process again.

Eating sugary processed foods can have a negative impact on your health and sometimes leads to weight gain.

Weight gain after quitting smoking

Sometimes people find that they gain weight when they quit smoking. This can be for several reasons.

As smoking triggers your ‘fight or flight’ response this can suppress your appetite. When you quit smoking you might crave the high that nicotine gives you. You might try to get it from other substances like sugar or caffeine. People who stop smoking also recover a sense of smell and taste and so they may find that enjoy food more than before. Smoking is also a habit which involves hand to mouth action and when people stop smoking they may find that they replace smoking with eating things like sweets and crisps.

To avoid or minimise weight gain after giving up smoking:

  • Try to drink lots of water to help your body flush out leftover toxins
  • Eat every three to four hours to regulate blood sugar
  • Make sure to have protein, healthy fat, fibre and fruit or vegetables in each meal or snack
  • Try to keep a regular sleep pattern

If you are craving sugar try to have a piece of fruit instead. Have it with protein and healthy fat, such as peanut butter.

Read more about dealing with withdrawal symptoms here.

Weight gain and body confidence

If you are worried about weight gain after quitting smoking, or are conscious that you have already gained weight, remember that your weight doesn’t define you. You are the same person with the same qualities and abilities no matter what you weigh or what size you are. The most important thing is that you are healthy. By giving up smoking you will definitely be healthier both in the short and long run.

If you are feeling bad about yourself remember to:

Learn more about how to improve your body image here.

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