Weight gain can be an unexpected side effect of cancer treatment

February 18, 2014 | by Nicole White

A side effect of cancer treatment many people don’t expect? Weight gain.

Weight gain is an often unexpected side effect of cancer treatment that can expose survivors to higher risk. Foods like fruits and vegetables, high in nutrients and fiber while low in calories, can help weight control. Weight gain is an often unexpected side effect of cancer treatment that can expose survivors to higher risk. Foods like fruits and vegetables, high in nutrients and fiber while low in calories, can help weight control.

People with certain cancers – such as breast, prostate and colon cancer – are more likely to gain weight during treatment due to the therapies used to combat their disease. Hormone therapy, some chemotherapy regimens and medications such as steroids  all can cause weight gain, as well as water retention.

Other treatments can increase appetite or cause fatigue – which can lead to eating more and moving less, a common formula for weight gain. In other cases, old-fashioned stress and “comfort” food could be triggers for weight gain.

Some studies of cancer patients have linked obesity to an increased risk of recurrence and death in several common cancers, including breast, colorectal and prostate cancer. The California Teachers Study, led by City of Hope’s Leslie Bernstein, showed that being obese was associated with a significant increase of dying from breast cancer for many women.

Patients currently in treatment, however, shouldn't go on a diet – even if they find themselves gaining weight – without speaking to their physician. A doctor can help determine why weight is increasing and discuss the options.

The population of cancer survivors in the U.S. is on the rise at the same time as the obesity rate is increasing – to the point that two-thirds of adults are obese or overweight – so naturally, the number of cancer survivors struggling with their weight also has increased.

Sometimes, survivors and their families don’t realize that significant and lasting weight gain can be a serious health problem. For example, a National Cancer Institute-funded study found that adult survivors of pediatric acute lymphoblastic leukemia were significantly more likely to be obese than their siblings. Other trials aimed at helping cancer survivors lose weight found that families – relieved that a child has overcome life-threatening illness – often see weight as a comparatively minor health issue. However, obesity puts survivors at increased risk of cancer, a risk that is already elevated for cancer survivors.

The good news is that dropping the weight and adding moderate amounts of exercise will go a long way to reverse these risks.

“Physical activity is stronger in its ability to cut cancer risk than even maintaining a healthy body weight, particularly for women,” said Leslie Bernstein, Ph.D., R.N., professor and director of City of Hope’s Division of Cancer Etiology.

The National Cancer Institute offers these tips for managing food and managing food, weight and cancer risk:

  • Reach for high-fiber foods. Fruits and vegetables are nutrient-rich, as well as high in fiber and low in calories. Whole-grain breads, cereal and pastas will help you stay fuller longer. (Again, if you’re currently a cancer patient, check with your doctor, as fiber should be restricted for some patients.)
  • Find a lean protein fix. Lean meats are best. Skinless chicken, lean beef and pork trimmed of fat are good sources of protein. Low-fat and nonfat yogurt and skim milk are also good sources of protein.
  • Cut down on fats. Minimize butter, mayo, creamy condiments, desserts, fried foods and other calorie-dense foods. Broiling, steaming, grilling and roasting foods are also a good way to minimize using fats in the preparation of foods.
  • Ask for support. Professionals like registered dieticians can provide excellent advice on managing food intake. Losing weight with the help and support of family and friends is also a winning strategy.
  • Don’t wait until you’re overly hungry to eat. That can lead to making poor food choices and eating larger portions.
  • Manage portions. Know what a single serving of meat looks like. Measure when you’re able, but also have some visual reference for when you eat out. For example, a single serving of meat is about the size of the palm of your hand (minus your fingers). Packing up half the serving a restaurant gives you to have for a later meal is also a good tip.



For more information about breast cancer, including risk factors, check out our breast cancer information page. For information about prostate cancer, including risk factors, check out our prostate cancer information page.


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