Former smokers gain four to five kilos in weight after they kick the habit, research suggests.

Researchers, based in the UK and France, found that former smokers gained an average of 4.67kg in the 12 months after they quit.

Most of the excess weight is gained during the first three months, they found.

former smokers gain weight

Ex-smokers pile on the pounds after kicking the habit

Analysing the results from 62 studies, the authors discovered that in the first three months after giving up, former smokers gain an average of 2.85kg.

Scroll down to see HuffPost's top tips on stubbing out the habit...

However, researchers found a large variation in weight change, with 13% of people gaining more than 10kg and 16% losing some weight.

The study, published on bmj.com, is accompanied by an editorial which suggests that health benefits from quitting outweigh the excess weight gain.

Esteve Fernandez, associate professor of epidemiology at the University of Barcelona, and Simon Chapman, professor of public health at the University of Sydney, said: "The relative long-term health effects of weight gain and smoking cessation also need to be considered with respect to the ultimate public health message that we should derive from this and future studies.

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"Although obesity is positively associated with an increased risk of all-cause mortality, cohort studies indicate that modest weight gain does not increase the risk of death; smoking does."

If you haven't managed to stub out the habit yet, take a look at these tips on quitting by Patrick Holford, a nutritional expert and author of How To Quit Without Feeling S**t:

  • Balance your blood sugar levels by eating low GI foods. For an example of which foods are best, take a look here.
  • In the first two weeks giving up, mix 8g of vitamin C with water and apple juice, as your immune system will start to kick in and this will strengthen your resistance to illness.
  • Take 50mg of niacin (vitamin B3) twice a day with food as this will reduce those pesky nicotine cravings.
  • If you have trouble sleeping due to the cigarette urges, take 100mg 5-HTP (a form of amino acid tryptophan) an hour before bed. This will help to naturally ease you to sleep.

Take a look at these experts tips on how to quit smoking by hypnotherapist, Elle Dormer...

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  • Five Ways To Quit Smoking

    Battle the addiction with these top tips by hypnotherapist, <a href="www.elledormerhypnotherapy.co.uk" target="_hplink"><strong>Elle Dormer</strong></a>.

  • Close Your Eyes

    "Close your eyes and take 3 deep breaths in and out. Now build a mental picture of yourself in the future as a non smoker. "Make it real by filling in the detail - where you are, what you're doing, who you're with and how much better you look and feel. This is known as future pacing. If you can imagine yourself having achieved your goal you a mentally a step closer to it."

  • Plan Your Escape

    "Smokers often use cigarettes as a form of escapism. To have a break away from their desk after a stressful call. Or to provide thinking time when they are procrastinating. "Go for a brisk walk instead. Or to the kitchen to make a cup of tea. Any simple, familiar task that we can do without much thought allows us to simultaneously access our unconscious or 'zone out' which can be both relaxing and enable greater creative thought."

  • Imagine Other People's Disappointment

    "Make a list of all the people (alive or dead) in your life who care for you - or have cared for you, like your friends, partner, parents or children. Then close your eyes and imagine them all together gathered in a room. "You are standing before them with a large beautifully gift wrapped box. This present represents you quitting smoking. Explain this to them in your mind. See or imagine their reactions. "Make them real. The relief, love, pride, appreciation. Then imagine asking for the gift back and how sad and disappointed they would be. And resolve that you cannot do this to the people you love."

  • Breathe!

    "Cigarettes do not relax you. Nicotine is a stimulant so it is actually making you edgier and more stressed by elevating your heart rate and releasing stress hormones like adrenalin and cortisol into your blood stream. "Try an experiment: replace one of your regular cigarettes of the day with the following pattern of breathing. Breathe in for a count of 4 and out for a count of 8. Do this 10 x, consciously relaxing your body on every out breath. "This will physiologically de-stress you by slowing your heart rate and releasing endorphins. And prove to you you can truly relax yourself without a cigarette.

  • Use Your Imagination

    "Take a moment somewhere quiet and close your eyes. Remember a time when you felt really confident, relaxed and in control. Take yourself back to that time, fill in the details and make it real. When you're feeling those emotions at their strongest, squeeze our thumb and forefinger together. "Clear your mind and repeat. Then practice recalling those helpful, positive emotions at points during the day by squeezing your thumb and forefinger together. The physical trigger should help to access those beneficial feelings that will help at moments of weakness."

Plus: Other surprise things that could be making you gain weight...

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  • Unlikely Things That Are Making You Fat

  • Snooping

    Research by psychotherapist Dawn Billings discovered that snooping at your partners phone or Facebook can lead to piling on the pounds. Billings claims that if you find something you didn't want to see, the stress of it all triggers the cortisol hormone, which interferes with the appetite-regulating hormone, letin. This can lead to an increase in hunger, making us lean towards emotional food binges.

  • Shampoo

    Scientists from the <a href="http://www.mountsinai.org/" target="_hplink">Mount Sinai Medical Center</a> claim that phthalates, the chemicals found in 70% of cosmetics including shampoo, throw the body's weight control system off kilter. These chemicals are also linked to depressing testosterone levels in the body, which can increase the risk of weight gain

  • Your Personality

    Recent research by the<a href="http://www.nia.nih.gov/" target="_hplink"> National Institute of Aging</a> found people who are highly emotional, organised and disciplined are more likely to be overweight. They also found that impulsive people have higher BMI's than those who are more relaxed and laid back.

  • Spanx

    Although its sole purpose is to disguise any unsightly lumps or bumps, it could give wearers a false sense of security, meaning they ditch diets as they know their pair of <a href="http://www.spanx.com/home/index.jsp" target="_hplink">Spanx</a> knickers will hold in their muffin top.

  • Diet Drinks

    Those who guzzle diet fizzy drinks in the false hope that they're being healthier than drinking the full fat version, are still at risk of gaining weight. According to a study by the <a href="http://www.utexas.edu/" target="_hplink">University of Texas</a>, people who drink diet drinks see their waistbands expand 70% faster than those who drank normal fizzy drinks. This is because they believe they can drink more because of its lower calorie-count.

  • Your Boyfriend

    Falling in love can make you fat, research by the <a href="http://www.uconn.edu/" target="_hplink">University of Connecticut</a> has discovered. Otherwise known as the 'boyfriend layer', when a relationship becomes more established, couples tend to relax their fitness regime, eat out more - and eat more food. This is because new couples 'bond' over food and spend a lot of time doing sedentary things, like lounging on the sofa or in bed.

  • Work

    Women who are fed up at work are more likely to comfort eat, a study by the <a href="http://www.umassmed.edu/index.aspx" target="_hplink">University of Massachusetts Medical School</a> has found. Those who are hacked off with their everyday routine find comfort in 'emotional eating' when stressed and anxious rather than eating when hungry.

  • Your Bed

    Lack of sleep disrupts the body's natural circadian pattern, which controls moods, alertness and appetite over a 24-hour period. If this is altered, it causes an imbalance in the leptin hormone (the hormone that tells us when we're full) and the ghrelin hormone (the hormone that tells us when we need food for energy). If these are out of control for regular periods, it can lead to weight gain.