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Cancer Risk and Prevention

What Does the American Cancer Society Recommend About Body Weight?

To help lower your risk of cancer

As part of its Guideline for Diet and Physical Activity for Cancer Prevention, the American Cancer Society recommends that people try to get to and stay at a healthy weight throughout life. The best way to stay at a healthy body weight is to balance how much (and what) you eat with how active you are. If you are overweight, the best way to get to a healthy body weight is to limit the calories you take in, and burn more calories through physical activity.

Follow a healthy eating pattern: You can lower the number of calories you take in by eating healthier foods; eating smaller amounts of food (smaller portion sizes); limiting between-meal snacks; and limiting foods and drinks that are high in calories, fat, and/or added sugars, and that provide few nutrients. Fried foods, cookies, cakes, candy, ice cream, and regular soft drinks should be replaced with vegetables and fruits, whole grains, beans, and lower calorie beverages.

Be physically active: The American Cancer Society recommends that adults get 150 to 300 minutes of moderate intensity or 75 to 150 minutes of vigorous intensity activity each week (or a combination of these). Getting more is even better. Children and teens should get at least 1 hour of moderate or vigorous intensity activity each day.

It’s also important to limit the time you spend sitting, lying down, watching TV, and looking at your phone or computer. Doing some physical activity on top of your usual activities, no matter what your level of activity, can have many health benefits.

Along with helping you get to or stay at a healthy weight, eating a healthy diet and increasing your physical activity can have their own health benefits, including lowering your risk of cancer.

For people already diagnosed with cancer

More and more evidence suggests that being overweight or obese raises the risk of cancer coming back after treatment and may lower the chances of survival for many cancers. Both during and after cancer treatment, people should try to get to and stay at a healthy weight whenever possible.

Some cancer survivors can be malnourished and underweight when they are diagnosed or as a result of cancer treatment. These people may need help gaining or maintaining their weight.

Other people may be overweight or obese when they are diagnosed with cancer. While each person’s situation can be different, many people may choose to wait until after treatment is finished before making lifestyle changes that could result in weight loss. Others may choose to talk with their doctor about whether to try to lose modest amounts of weight during treatment, assuming it is monitored closely and does not affect treatment. If a person chooses to try to lose weight, it should be done safely, through a well-balanced diet and increased physical activity tailored to their specific needs.

After cancer treatment, weight should be managed with both dietary and physical activity strategies. One way to help get to a healthy weight is by reducing calorie intake. This can be done by eating lower-calorie foods (such as vegetables, fruits, and soups, and cooked whole grains), limiting your intake of fat and sugars, and limiting portion sizes – especially of high-calorie foods. Increased physical activity is also important in promoting weight loss, and in keeping weight off. Even if an ideal weight is not reached, it’s likely that any weight loss will still have health benefits.

For more information, see Nutrition and Physical Activity During and After Cancer Treatment: Answers to Common Questions.

The American Cancer Society medical and editorial content team

Our team is made up of doctors and oncology certified nurses with deep knowledge of cancer care as well as journalists, editors, and translators with extensive experience in medical writing.

Rock CL, Doyle C, Demark-Wahnefried W, et al. Nutrition and physical activity guidelines for cancer survivors. CA Cancer J Clin. 2012;62(4):242-274.

Rock CL, Thomson C, Gansler T, et al. American Cancer Society guideline for diet and physical activity for cancer prevention. CA Cancer J Clin. 2020;70(4). doi:10.3322/caac.21591. Accessed at on June 9, 2020.

Last Revised: January 22, 2021

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