Jan 1, 2003 Table of Contents

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 But medical information is always changing, and some information given here may be out of date.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 familydoctor.org, the AAFP patient education Web site.

Information from Your Family Doctor

What It Takes to Lose Weight

Am Fam Physician. 2003 Jan 1;67(1):149-150.

What does it take to lose weight?

To lose weight, you have to cut down on the number of calories you consume and start burning more calories each day. The amount of energy in the food you eat is called calories. Some foods have more calories than others; for example, foods high in fat and sugar are also high in calories. Your body uses calories for energy. If you eat more calories than you use, the extra calories will be stored as body fat.

A pound of fat is about 3,500 calories. To lose one pound of fat in one week, you have to eat 3,500 fewer calories (that is 500 calories a day), or you have to “burn off” an extra 3,500 calories. You can burn off calories by exercising and just by being more active.

You can lose weight by just eating fewer calories. But if you don't exercise at the same time, the weight will come back if you start eating more calories. To lose weight and keep it off, you need to cut calories and burn off calories. You can cut 250 calories from your diet each day and exercise enough to burn off 250 calories. That adds up to 500 calories you can get rid of in one day. If you do this for seven days, you can lose one pound of fat in a week. (Talk to your family doctor before you begin any type of exercise program. Your doctor may be able to tell you what kind of exercise program is right for you.)

Many experts believe you should not try to lose more than two pounds a week. Losing more than two pounds in a week usually means that you are losing water weight and breaking down muscle mass instead of losing fat. If you do this, you will lose energy, and you will probably gain the weight back.

How often should I eat?

Most people should eat three regular meals and one snack every day. The three meals should be about the same in size and should be low in fat. At breakfast, lunch, and dinner, it's good to eat two or three servings of fruits and vegetables, one serving of grains, and one serving of meat or a meat alternative.

Some people benefit more if they eat five to six smaller meals throughout the day, about two to three hours apart. For example, their first meal of the day might be a cup of yogurt and a banana. Three hours later they might eat a simple deli sandwich.

Don't skip meals. While this may help you lose weight for a little while, it fails in the long run. You get too hungry and then eat too much at once. You may get so used to skipping meals that you don't feel hungry at normal mealtimes. But after about a month of eating a normal breakfast and lunch and a light dinner, your body will adjust.

What is so bad about high-fat foods?

Fat has almost twice the calories of carbohydrates and protein. Fat calories turn into body fat easier than carbohydrates or proteins. Fat in your diet can confuse your appetite, so it doesn't tell you when you are full.

Can I trust nutrition information I get from newspapers and magazines?

Nutrition tips from different sources sometimes conflict with each other. You should always check with your doctor first. Also, keep in mind this advice:

  • There is no “magic bullet” when it comes to nutrition. There isn't one diet that works for every person. You need to find a diet that works for you.

  • Good nutrition doesn't come in a vitamin pill. You can take a vitamin pill to be sure you're getting enough vitamins and minerals, but your body benefits the most from eating healthy foods.

  • Eating all different kinds of foods is best for your body. Learn to try new foods.

  • Fad diets offer short-term changes, but good health comes from long-term effort and commitment.

  • Stories from people who have used a diet program or product, especially in commercials and infomercials, are just a way to sell more of the product. Remember, weight gain or other problems that come up after the program is over are never talked about in the ads.

Will diet drugs help?

Although diet drugs may help you lose weight at first, they usually don't help you keep the weight off. Taking drugs does not help you learn to change your eating and exercise habits. Making lasting changes in your eating and exercise habits is the way to lose weight and keep it off.


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 http://familydoctor.org.

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.

Copyright © 2003 by the American Academy of Family Physicians.
This content is owned by the AAFP. A person viewing it online may make one printout of the material and may use that printout only for his or her personal, non-commercial reference. This material may not otherwise be downloaded, copied, printed, stored, transmitted or reproduced in any medium, whether now known or later invented, except as authorized in writing by the AAFP. Contact afpserv@aafp.org for copyright questions and/or permission requests.

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