Weight gain doesn’t always depend on diet, genes, or lack of exercise. Other factors like quitting smoking and taking medications can cause you to gain unwanted pounds no matter how closely you follow a diet.
You may gain up to 10 pounds when you quit smoking, but most people return to their normal weights at the end of a year. The gain, according to research, seems to be due to eating extra calories in the first month after you quit and peaks at about six months. Although it’s not clear why quitting smoking leads to weight gain, it’s likely that nicotine somehow increases metabolic rate and quitting smoking lowers it.
When researchers followed 9,000 women for two years, they found that smokers who quit and added one to two hours of vigorous physical activity each week averaged a 4-pound weight gain; former smokers who did not exercise averaged a gain of 8 1/2 pounds. Even more beneficial was exercising two or more hours per week.
Light smokers had an average gain of just 3 pounds, and heavy smokers gained 6 pounds. By comparison, light smokers who quit but did not change their activity level gained 5 pounds on average, and heavy smokers nearly 9 1/2 pounds. Meanwhile, women who continued to smoke still gained, too: about one pound during the study.
If you find that you’re gaining weight on a long-term medication that your doctor has prescribed for you, discuss the possibility of switching to a different brand. Medications have different side effects, even if they’re in the same class or family, so your doctor may be able to find one that works better for you. The drugs listed in the following table are strongly associated with weight gain.
| Type of Medication | Brand Names | Used to Treat |
|---|---|---|
| MAO inhibitors | Marplan, Nardil, Parnate | Depression |
| SSRIs | Prozac, Zoloft, Paxil | Depression |
| Tricyclic antidepressants (amitriptyline, imipramine, desipramine, clomipramine, and so on) | Elavil, Tofranil, Norpramin, Anafranil, and others | Depression, urinary incontinence |
| Mirtazapine | Remeron | Depression |
| Lithium carbonate | Eskalith, Lithobid, Lithonate, Lithotabs | Mood disorders, seizures |
| Valproic acid | Depakene | Seizures |
| Carbamazepine | Carbatrol, Epitol, Tegretol, Tegretol XR | Seizures |
| Olanzapine | Zyprexa | Psychotic disorders |
| Clozapine | Clozaril | Schizophrenia |
| Corticosteroids | Prednisone, Vanceril, Flovent | Asthma |
| Sulfonylurea derivatives | Glucotrol, Orinase, Diabinese, Amaryl, Avandia, | Noninsulin dependent (type 2) diabetes |
| Antineoplastic agents | Tamoxifen | Breast cancer |