Weight loss used to be a great cause for worry after someone was diagnosed with cancer, but researchers now say that excessive weight gain is possibly worse. Experts currently recommend that cancer survivors should control their weight and exercise regularly to improve their long-term health.
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Many people who develop a common cancer like breast or colon cancer tend to gain weight. Unfortunately, a study within the Nurses’ Health Study of more than 5,000 women showed that normal weight women who gained weight after diagnosis of their breast cancer were less likely to survive.
Women who gained only a moderate amount on average about six pounds were 35 percent more likely to die from cancer than those who maintained their weight. Women who gained larger amounts averaging about 17 pounds were 64 percent more likely to die from cancer. This same study also confirmed the well-documented connection between overweight nonsmokers and a risk of breast cancer after menopause.
The researchers of this study found that exercise improved the odds of survival in women who developed breast cancer. Women who spent the equivalent of three to five hours a week moderately walking cut their risk of death in half compared to women who walked less than an hour a week. Exercising more than five hours a week showed no additional benefit in this study.
According to Wendy Demark-Wahnefried, a professor at Duke University Medical Center, women who receive adjuvant chemotherapy for breast cancer often rapidly develop “sarcopenic obesity.”
This kind of weight increase results from gains in body fat and loss of lean muscle. These undesirable changes in body composition can be avoided, however. A controlled study of recent breast cancer survivors found that strength-training twice a week for six months produced increased muscle mass and a decreased percentage of body fat. This form of exercise uses weights or other resistance to build stronger muscles.
One of the reasons that cancer survivors sometimes give for not exercising is fatigue. However, a review of 33 studies on exercise and cancer patients revealed that appropriate programs could improve these people’s physical states without increasing their symptoms of fatigue.
A study is now under way, funded by a grant from the American Institute for Cancer Research, to examine the effects of a practical diet and exercise program for overweight women who have undergone breast cancer treatment. Calories will be reduced in their diet to promote weight loss, but they will eat more vegetables and fruits. The women will also do aerobic exercise three to five days a week. The researchers will test the program’s effect on the women’s weight, as well as on their body muscle, percentage of fat, psychological status and markers associated with disease recurrence.
Many of the previous studies about the impact of people’s weight and exercise on their survival after cancer have involved breast cancer patients. Since a person’s energy balance, weight control and exercise level also seem related to the risk of developing colon, uterus, kidney and prostate cancers, it seems likely that people who had these cancers may also benefit from healthy diet and exercise changes.
After a diagnosis of cancer, people often ask what they can do to improve their odds of survival. For years, we didn’t have enough research for a good answer. While we wait for a better answer, maintaining or aiming for a healthy weight and getting regular moderate exercise may help. Cancer survivors would be wise to discuss with their physicians what steps might be appropriate for them. The benefits may be more than you can image.
Nutrition Notes is provided by the American Institute for Cancer Research in Washington, D.C.
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