When you smoke, the Smoking throughout the day can burn nearly 150-200 calories of your body. In this way somehow your weight remains intact. Though often smoking is associated to weight gain, the smokers who quit smoking face the burden of weight. Once you quit smoking, the calorie count of your body increases because the body no longer burns the 150-200 calories anymore. But such cases are not universal. It varies from person to person. Some person tend to gain weight while other loss and the rest remains more or loss same.
There is another reason for weight gain in those who quit smoking. To keep off crave of nicotine doctors often suggest them to eat some other food stuff. In this way unmindfully you eat more than your body requirement. The good news is that the weight gain is not permanent. You can beat it to the blues if you maintain a regular healthy life-style of balanced diet and exercise.