Q: How can I give up smoking without piling on the pounds as I have done in the past?

A: It is pretty normal for weight to creep on - or in some cases to pile on - when you give up smoking (average gains are 15.4lb after 12 weeks, with 10 per cent of quitters putting on more than 2st by this point). It's important for you to understand the reason for this and that your history of gaining is probably not simply down to consuming huge amounts of extra food.

First, there is the simple fact that the nicotine in cigarettes speeds up your metabolism. This effect lasts for about 30 minutes after each cigarette. On giving up, the number of calories you burn can drop by 150-300 per day, depending on how many cigarettes you smoked and your individual metabolism.

Second, nicotine also has the effect of suppressing your appetite; probably by blocking the chemical brain transmitter known as neuropeptide Y. In giving up, levels of this transmitter increase along with your appetite.

When it comes to diet, most advice focuses on having healthy snacks to hand to help you to make up for the loss of oral satisfaction that putting a cigarette in your mouth used to achieve. Fair enough, but understanding the real physiological reasons for weight gain can be hugely helpful as well, because forewarned is forearmed.

If you know why you are fighting an uphill metabolic as well as behavioural battle, it is easier to face reality, plan ahead and stop beating yourself up, thinking that your gains are just because you have no willpower around food.

Start by working out how many calories you are currently consuming each day. When you give up, you need either to plan to deliberately eat about 300 fewer, or to do 300 calories' worth of activity each day to make up for the fall in metabolism - for example, about an hour's walk or 30 minutes' jogging each day.

When planning your day's meals, count in some “distraction” snacks for when you need to do something with your hands and have something in your mouth. Things like apples and sugar-free gum may sound dull but they are practical and will help. Try also to eat foods that will help to keep you feeling full to counteract your increase in appetite. Having protein at each meal such as milk, yoghurt, lean bacon or eggs for breakfast and meat, fish, eggs, chicken, pulses or tofu at lunch or dinner, along with slowly digested carbohydrates such as multigrain, rye or pitta bread, tortilla wraps, pasta or sweet potato will certainly help.

It is hard to overemphasise the need to plan the timing of your meals, especially breakfast. Smokers often skip breakfast, preferring a cigarette instead. Continuing with this habit once you quit will mean that your blood sugar levels will be in your boots by mid-morning - which will coincide, especially in the first week of giving up smoking, with your worst physical feelings of nicotine withdrawal.

At least if your blood sugar levels are stable after a breakfast of something like boiled eggs and toast or a big bowl of porridge, you will only (and I don't say this lightly) be dealing with the nicotine craving and not feeling light-headed and faint through lack of food as well.

People who smoked 24 cigarettes a day or fewer have been shown to limit their weight gain on giving up to an average of 4lb by doing 1-2 hours of vigorous physical activity each week.

According to Dr Douglas E. Jorenby, of the University of Wisconsin Medical School in the US, in a study of more than 200 smokers those on the nicotine patches reported lower appetites, and gained less weight, than those given patches containing no nicotine.

A pilot study at the Roswell Park Cancer Institute in New York revealed that taking 450mg of standardised extract of St John's Wort (such as Kira St John's Wort) twice a day one week before a set quit date and then during a 12-week follow-up may aid giving up smoking by helping to combat the depression that often accompanies quitting.

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