When people stop smoking, they commonly gain weight.
Most people think that they are substituting food for cigarettes.
This is partially correct. Smoking is usually a different form of oral gratification that obviously does not involve the consumption of calories. However, smoking does have another effect - it actually increases caloric requirements. An excellent way to help counter this is to exercise consistently. For example, start walking 30 minutes a day three to four times a week - a very feasible goal.