Diet and Cancer Treatment

Nutritional planning and management for people with cancer.

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.

Malignancies directly compromise nutritional status by altering metabolism and causing loss of appetite. Changes in metabolism include an increased basal metabolic rate and increased total energy expenditure. This elevation in energy use means you’ll require more calories to maintain your current weight and lean body mass.

There are also individual alterations in carbohydrate, protein, and fat metabolism. These changes contribute to the loss of skeletal muscle and adipose tissue (fat) stores. Cancer-associated anorexia is probably the result of physiological changes but may also be due to a psychological response to the disease.

There are several factors that may contribute to the type and degree of nutrient deficiencies:

  • the primary organ where the malignancy occurs
  • the severity of the cancer at the time of diagnosis
  • the symptoms experienced by the person with cancer
  • the type and frequency of the cancer treatment being used and the side effects associated with that treatment (surgery, radiation, or chemotherapy)
  • the effect of the malignancy or disease on food and nutrient ingestion, tolerance, and utilization

Food Sources
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. High-protein foods with a lower fat content must then be incorporated (low-fat shakes, yogurt, cottage cheese, lean meats).

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

Side Effects
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 complement, medication that may be used to alleviate these symptoms.

Thick consistency liquids such as milkshakes or semi-solid foods like mashed potatoes and gravy may be easier to swallow and will help prevent aspiration (inhaling food).

Eating a meal immediately before or after the administration of the treatment may alleviate these symptoms.

The patient’s position while eating may also contribute to these symptoms.


  • Give bland foods. Avoid strong flavors like spices, acidic foods, and sour tasting foods.
  • Provide cold foods; avoid hot or warm foods.
  • Avoid giving foods with strong odors.
  • If a person is experiencing severe nausea, avoid offering a person their “favorite food” unless they request it. Eating a food during severe bouts of nausea may cause them to develop an aversion to it.


  • Increase protein and calories in the diet.
  • Eat smaller, but more frequent meals.
  • Add powdered milk to foods and beverages.
  • Drink mainly calorie-containing beverages such as juices, milk, or sweetened drinks.
  • Add extra eggs or egg whites to foods. Never use raw eggs as they may contain salmonella which would further compromise a person who is immune- suppressed. Raw eggs also contain a vitamin binder.
  • Add diced meat or cheese to sauces, vegetables, soups, and casseroles.
  • Snack throughout the day on calorie-dense foods such as nuts, hard candy, and dried fruits.
  • Consider using commercially available nutrition supplements. You can make your own high-calorie shake by using an instant breakfast drink mix with milk, fruit, cookies, peanut butter, or other favorite mixers.
  • Increasing fats in the diet is an excellent way to increase energy consumption, if you are tolerating fats. Add margarine or butter to breads and vegetables. Add gravies and sauces to foods in liberal amounts.
  • If you are unable to digest fat, consult with your physician or dietitian for alternative fat sources. Supplements containing medium-chain triglycerides are often recommended for this purpose.

Some cancer patients become unable to digest dairy products (lactose intolerant). Symptoms include bloating, gas, and diarrhea immediately after ingesting 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.

Some cancer treatments cause “dumping syndrome.” If you have dumping syndrome, food is “dumped” into the jejunum (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 jejunum 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:

  • eat smaller, more frequent meals
  • lie down immediately after eating
  • restrict refined carbohydrates and increase protein and fat in the diet
  • restrict fluids to 30 minutes before a meal and 30-60 minutes after a meal

If you are experiencing anorexia, adjust the diet to include any foods that appeal to you. Consult with your physician for consideration of appetite-stimulating drugs.

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

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

Objectives for a cancer treatment diet:

  • To achieve and/or maintain optimal nutrition status
  • To maximize the benefits of therapy the patient is receiving
  • To reduce symptoms caused by the therapy
  • To prevent or reverse loss of subcutaneous fat