Many people are concerned they might gain weight after quitting smoking. However, not everyone who quits smoking gains weight. In fact, some people actually lose weight! For those who put on weight the average gain is 5 to 7 pounds. Of course, some people do put on much more weight.
People gain weight for a lot of reasons. For example, after you stop smoking, you may be tempted to eat more because your food will smell and taste better. You may eat as a substitute for keeping your hands and/or mouth busy. You may also gain weight because nicotine is a stimulant that artificially increases your metabolism. Sometimes people gain weight because they feel hungrier after they quit smoking. Finally, you may gain weight because subconsciously you believe you have a legitimate reason for doing so.
If you are concerned about weight gain, keep this fact in mind. The health damage of a pack of cigarettes a day is about the same as carrying 60 or more extra pounds. The more you smoke, the more weight you'd have to put on to negate the health benefits of quitting smoking. Keep in mind that quitting smoking will reduce premature wrinkling of the skin and premature aging.
You will be less likely to gain weight if you:

Using the nicotine patch or gum or buproprion as part of your quit attempt may also slow weight gain.
Individuals who are more physically active before they stop smoking are also much less likely to gain weight. Starting a moderate active living routine a few weeks before attempting to stop smoking may help.

Some people are able to make several lifestyle changes at the same time. However, most people find it easier to tackle one challenge at a time. Instead, try to maintain your usual diet or snack on healthier foods. If you do gain weight, try losing it by adopting healthy eating behaviours and increasing physical activity levels a few weeks after you have remained smokefree. Alternatively, try adopting a healthier diet and activity patterns a few weeks before you try to quit smoking. The confidence and skills you gain from changing one type of behaviour can help you with changing other behaviours.
For more good information on smoking and weight go to:
Saskatchewan Lung Association
For a copy of the Canada's Food Guide to Healthy Eating, go to:
Health Canada