It's very important to maintain good nutrition before, during, and after cancer treatment. Treatments may involve radiation therapy, chemotherapy, hormone therapy, biological immunotherapy, surgery, or a combination of these. These procedures and medicines can cause many people to lose their appetite and energy. This puts them at an increased risk for malnutrition.

Your food choices when you have cancer and are having treatment may be very different from what you are used to eating. The main goal is to try to keep your weight constant. In order to minimize weight changes, heal properly, and maintain the energy to cope with all the new challenges treatment may bring, you may be told to eat a wide variety of high-calorie and high-protein foods. These include:

• Milk, cream, and cheese

• Cooked eggs

• Sauces and gravies

• Butter, margarine, and oil

Sometimes the recommendations given to you will seem like the opposite of what you have always heard a healthy diet should include. But your doctor may encourage you to follow a high-calorie, high-protein diet. This is especially true if you are feeling weak or are underweight. It can be a challenge to get enough nutrients because you may not feel well or may not feel like eating. Proper attention to nutrition can help you recover.

Eating well before cancer treatment begins may help to increase your energy. It can also improve your sleep. To prepare yourself and your home for your nutritional needs during cancer therapy, think about the following suggestions:

• Stock the refrigerator with plenty of your favorite foods so that you won't have to shop as often. Make sure these are foods you can eat when you are not feeling well.

• Cook large portions of your favorite dishes in advance and freeze them in meal-sized portions.

• To save your energy, buy foods that are easy to prepare. Examples are peanut butter, pudding, frozen dinners, soup, canned fish or chicken, cheese, and eggs.

• Ask family and friends to help you cook and shop.

• Talk with a registered dietitian about meal planning, grocery shopping, and reducing side effects of treatment, such as nausea and diarrhea.

• Talk with your healthcare provider or registered dietitian about whether you should take a multivitamin.

By planning ahead, you will have foods on hand that you like to eat. This will benefit you later. You will have good things to choose from in your kitchen, even if you do not feel well enough to make an elaborate meal. You may also come to think differently about your weight. If you have been concerned in the past about weight gain, your focus will likely change to eating enough to keep your weight constant.

Before treatment begins, cancer itself can cause problems that may result in eating problems or weight loss. It is not uncommon to have problems with milk sugar (lactose intolerance), nausea, vomiting, poor digestion, or a feeling of early fullness, sleepiness, and forgetfulness even before treatment for cancer.

Lactose intolerance is a condition in which your body can't digest or absorb the milk sugar called lactose. This is usually because of the lack of the enzyme lactase. Lactase helps to break down lactose so you can digest it. People with cancer often have lactose intolerance. Symptoms include diarrhea, gas, bloating, and stomach pain or cramps. If you have some of these symptoms after eating dairy products, talk with your healthcare provider or dietitian. You may need to limit the amount of dairy you consume.

Dairy products such as milk, cheese, ice cream, yogurt, and sherbet contain lactose. Certain prepared foods have dairy products in them that also contain lactose. Many other foods may also have hidden sources of lactose. Check the labels of products to  find out if they contain milk, milk by-products, or lactose. Look for terms such as:

• Milk

• Milk solids

• Skim milk powder

• Cream

• Buttermilk

• Malted milk

• Whey lactose

• Curds

• Dry milk solids

• Nonfat dry milk

These foods contain lactose and you should make sure that you tolerate them. Some foods that may have hidden sources of lactose include:

• Breads

• Candy

• Cookies

• Cold cuts and bologna

• Hot dogs

• Sauces, gravies, and salad dressings

• Cream soup

• Dessert mixes

• Frostings

• Chocolate drink mixes

• Margarine

You may not need to eliminate lactose-containing foods entirely from your diet because your body makes small amounts of lactase. Lactose levels vary in foods. Hard cheeses and yogurt have the least amount of lactose. Learn how much lactose you can tolerate by trying one-fourth cup of milk and gradually increasing your intake. Because lactose intolerance is not an allergy, there are no long-term health problems if you accidentally eat or drink lactose. Symptoms will ease as the lactose moves through your digestive system.

You may have to substitute other things for the dairy products you are used to eating. It's important to add other sources of calcium when foods containing lactose are dropped from your diet. You may try a lactose-free or low-lactose milk. This milk has the lactose reduced or removed. Your healthcare provider or registered dietitian can give you more information about this product.

The U.S. Dietary Reference Intake for calcium is 1,000 milligrams (mg) per day for adults ages 50 and younger. For women over 50 and men over 70, the recommendation increases to 1,200 mg of calcium per day. If you are not using milk or milk products, you may not be getting enough calcium to build and maintain strong bones and teeth. The following foods are good sources of calcium. A registered dietitian can also provide additional suggestions.

• 50 to 100 mg of calcium

  • 1 cup broccoli

  • 1/2 cup okra

  • 5 oz. shrimp

  • 1/2 cup turnip greens, kale, or collards

  • 1/4 cup almonds

• 100 to 300 mg of calcium

  • 2 oz. canned sardines

  • 1/2 cup tofu

  • 1 1/2 cups dried beans

  • 4 oz. canned salmon

• 300 to 400 mg of calcium

  • 1 cup calcium fortified orange juice

  • 1 cup calcium-fortified soymilk

  • 1 cup yogurt

Cancer treatment may cause you to feel very tired. So you may not feel like starting a new exercise program. Light, daily exercise before you start to feel tired will make it easier for you to continue regular daily physical activity after your treatment begins.

Once you begin treatment, light, regular physical activity is very good for you. It will improve your appetite, stimulate digestion, prevent constipation, and give you more energy. Physical activity will also help lower stress, improve mood, and maintain muscle tone. Always talk with your healthcare provider before beginning any exercise program.