There are more than one half million cancer deaths in the United States each year, and one third of these deaths are attributed to sub-optimal diet and physical activity practices. Maintaining a healthy weight, staying physically active throughout life, and consuming a healthy diet can substantially reduce the lifetime risk of developing cancer, as well as influence overall health and survival after a cancer diagnosis.
The American Cancer Society’s Nutrition and Physical Activity Guidelines serve as a source document for communication, policy, and community strategies to improve dietary and physical activity patters among Americans. In 2006 they published updated guidelines for the primary prevention of cancer and guidelines for improving outcomes among cancer survivors through tertiary prevention.
The two sets of guidelines have similar recommendations, including: achievement and maintenance of a healthy weight; regular physical activity of at least 30 min per day and at least five days per week; a plant-based diet high in fruits, vegetables, and whole grains and low in saturated fats and red meats; and moderate alcohol consumption, if at all.
The strongest current evidence for primary prevention and for improving outcomes after a diagnosis of cancer relates to the achievement of a healthy weight. Overweight and obesity are known risk factors for several types of cancers, and the evidence is increasing for other types. Thus, cancer survivors and persons hoping to reduce their primary risk of cancer should be encouraged to achieve and maintain a healthy body weight (BMI = 18.5-24.9 kg per m2).
Strong evidence also suggests that increased levels of physical activity reduce the riks for colorectal and breast cancers. In addition, evidence of benefit is accumulating for cancer survivors. Moderate-to vigorous levels of physical activity of at least 30 min per day on at least five days per week are recommended, although benefits related to colorectal cancer may require higher levels, i.e., at least 60 minutes per day). Some examples of moderate-intensity activities include: walking; dancing; horseback riding; yoga; golfing; mowing the lawn; and job-related walking and lifting. Examples of vigorous-intensity activities include: jogging or running; fast bicycling; circuit weight training; aerobic dance; soccer; cross-country skiing; and heavy manual labor (e.g. forestry, construction).
Alcohol is associated with a higher risk for a variety of cancers. Risk is largely apparent at levels of more than two drinks per day for men and more than one drink per day for women. However, moderate alcohol consumption is protective against cardiovascular disease, a significant comorbid condition among cancer survivors.
Physicians are encouraged by the American Academy of Family Physicians to find teachable moments to impart appropriate nutrition, physical activity, and weight management guidance to their patients and to support policies and programs that can improve these factors in the community to reduce cancer risk and improve outcomes after cancer.
Amercian Family Physician June 1, 2008. Volume 77, Number 11 pp1573-1578.