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Diet - cancer treatment

Contents of this page:

Alternative Names   

Cancer treatment and nutrition

Definition    Return to top

People with cancer need special nutritional planning and management.

Function    Return to top

People with cancer are at risk for developing nutritional deficiencies. The deficiencies may be the result of the cancer itself, or the side effects of common cancer treatments such as surgery, chemotherapy, and radiation therapy.

Cancer directly affects your nutritional status by changing the body's metabolism and causing you to lose your appetite. Your body increases energy use, which means you need more calories to maintain your current weight and lean body mass. Cancer-associated loss of appetite is probably the result of physical changes but may also be due to a psychological response to the disease.

Cancer also causes individual changes in the body's ability to break down carbohydrates, protein, and fat. These changes lead to the loss of muscle and fat.

Several things may contribute to the type and degree of nutrient deficiencies:

Food Sources    Return to top

People with cancer frequently require a high-calorie diet to prevent weight loss. They may also need a diet that is high in protein to prevent muscle wasting. Foods that are high in calories and protein include peanut butter, whole milk, milkshakes, meats, and cheeses.

Some individuals with cancer develop an aversion to fats. If this happens, eat high-protein foods with a lower fat content such as low-fat shakes, yogurt, cottage cheese, lean meats.

For the diet to remain well-balanced, you must eat fruits and vegetables. To increase calories, use more fruit juices or dried fruits rather than whole fruits. Choosing calorie-dense vegetables such as corn and peas will also increase the calories in the diet.

Side Effects    Return to top

The side effects of common cancer therapies vary according to the treatment and the area of the body undergoing treatment. The following are some side effects and some helpful suggestions. They do not replace, but rather aid, drugs used to relieve these symptoms.


Thick liquids such as milkshakes or semisolid foods like mashed potatoes and gravy may be easier to swallow and are less likely to cause aspiration (inhaling food).


Eating a meal immediately before or after the administration of the treatment may ease these symptoms. Your position while eating may also contribute to these symptoms.




Some cancer patients become unable to digest dairy products, which is called lactose intolerance. Symptoms include bloating, gas, and diarrhea immediately after eating lactose-containing foods.

People with lactose intolerance have trouble digesting the sugar in milk. Lactose intolerance is due to an inability to produce lactase, the enzyme that digests milk. The wall of the gastrointestinal tract produces this enzyme. Fortunately, lactase can be synthetically produced, purchased over-the-counter, or can be taken orally with milk.

You can also buy lactose-free milk at most grocery stores. Cultured dairy products such as yogurt, cheeses, and buttermilk will have less lactose as the active cultures help to digest it. You may be able to tolerate small amounts of lactose occasionally. You may have to restrict lactose entirely from the diet until you have fully recovered from your cancer therapy.


Surgery on the stomach may cause dumping syndrome. If you have dumping syndrome, food is "dumped" into the small intestine 10 or 15 minutes after being swallowed. Ordinarily, food is partially digested in the stomach, then released gradually into the digestive tract.

The presence of undigested food in the intestine leads to abdominal fullness, nausea and crampy abdominal pain. Other symptoms include feeling warm, dizzy, and faint. You may also experience rapid pulse and cold sweats immediately after eating.

Recommendations for dumping syndrome are:


If you are experiencing loss of appetite, adjust the diet to include any foods that appeal to you. Consider asking your doctor about appetite-stimulating drugs.

Recommendations    Return to top

Objectives for a cancer treatment diet:

A registered dietitian is a trained health professional in the area of nutrition and can assist in nutritional planning for people with cancer.

Your local chapter of The American Cancer Society is an excellent resource for information on cancer prevention and treatment.

See also: Cancer - support group

Update Date: 7/22/2008

Updated by: Patrika Tsai, M.D., M.P.H., Assistant Clinical Professor, Pediatric Gastroenterology, Hepatology and Nutrition, University of California, San Francisco, San Francisco, CA. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

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