Please note: This information was current at the time of publication. But medical information is always changing, and some information given here may be out of date. For regularly updated information on a variety of health topics, please visit, the AAFP patient education website.

Information from Your Family Doctor

How Can I Lose Weight?


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Am Fam Physician. 2000 Apr 1;61(7):2143.

  See related article on obesity.

What causes weight gain?

We gain weight when we take in more calories than we burn off with exercise. Unless lean muscle is built by exercise, weight gain means mostly more body fat. In some cases, weight gain may also relate to our genes, the environment, our psychological state and other factors.

How much weight should I try to lose?

Talk to your doctor about your current weight and a healthy weight loss goal. You can improve your health a lot by losing as little as 5 to 10% of your present body weight. You should lose no more than about 1 pound a week. When you lose weight this slowly, you are more likely to keep it off.

What can I do to lose weight?

To lose body fat, you should eat fewer calories and increase your exercise. This may help you gain lean muscle to replace some of the fat you are losing. Your doctor can help you find a dietitian who can help you choose what to eat. Your doctor can also recommend an exercise plan for you. You should try to get 30 to 60 minutes of exercise, 4 to 6 times a week.

Do weight-loss medicines help?

Weight-loss medicines can help some obese people lose weight, but only when they are combined with a low-calorie diet and an exercise plan. Some weight-loss medicines include phentermine (brand name: Ionamin), sibutramine (brand name: Meridia), orlistat (brand name: Xenical), and phenylpropanolamine (brand name: Dexatrim). Discuss the risks and benefits of weight-loss medicines with your doctor before you try any.

Who should use weight loss medicines?

Weight-loss medicines are only for people who are obese—people who weigh about 20% more than the ideal for their height and body type. These medicines are not for people who just want to lose 5 to 10 pounds. Your doctor can tell you if weight loss medicines might help you.

Are there any side effects from using weight-loss medicines?

Yes. Some medicines may cause nervousness, irritability, headaches, dry mouth, nausea and constipation. Others may cause depression, drowsiness, abdominal pain, diarrhea, Your family doctor can tell you more about the side effects and help you decide whether to use a weight-loss medicine.

How can I keep weight off when I stop using the medicine?

Weight gain is common after the medicine is stopped. To keep the weight off you must permanently change your food and exercise habits. Remember, losing weight and keeping it off is a life-long effort.

This handout is provided to you by your family doctor and the American Academy of Family Physicians. Other health-related information is available from the AAFP online at

This information provides a general overview and may not apply to everyone. Talk to your family doctor to find out if this information applies to you and to get more information on this subject.


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