By Connie Giordano Ziembicki, MHSc, RD, Clinical Dietitian, Princess Margaret Cancer Centre

Treatment for brain tumours can include a combination of surgery, radiation, chemotherapy, immunotherapy and viral therapy. Radiation and chemotherapy work to destroy tumour cells, but they also cause side effects that affect your ability to eat. Nutrition plays an important role when you are experiencing these side effects.

Eating a balanced diet can help you:

  • Manage the effects of treatment
  • Fight off infections
  • Avoid weight loss or excessive weight gain
  • Repair cells and heal wounds by building new tissues
  • Feel better​

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​​​ Managing Side Effects During Treatment

Loss of Appetite

Loss of appetite is one of the common side effects people living with brain tumours experience with treatment. Short periods of loss of appetite may not be a problem. Prolonged loss of appetite leading to weight loss can pose a problem. Consult with a registered dietitian if you are experiencing weight loss as a result of loss of appetite.

If you are experiencing loss of appetite try:

  • Eating more when you feel the hungriest. For example, if you are hungriest in the morning then make breakfast your main meal.
  • Using small portions of food and get the satisfaction of finishing a meal.
  • Eating a number of small meals and snacks during the day instead of 3 large meals. Try to eat every 2-3 hours.
  • Having ready-to-eat snacks such as cheese and crackers, pudding, ice cream, yogurt, muffins, nuts, and seeds.
  • Having a regular meal schedule. This will remind you to eat.
  • Choosing a liquid nutritional supplement at meal or snack time if food is not appealing.


People receiving treatment for a brain tumour sometimes develop diabetes. Diabetes is a condition in which the body cannot use sugar properly. Some drugs, such as decadron, may cause the development of diabetes. The diabetes may also be due to the cancer itself.

A proper diet is important when you have diabetes. It helps to control your blood sugar. Consult with a registered dietitian about designing a plan that meets your personal requirements. You can also try:

  • Eating 3 meals a day and snacks.
  • Eating at the same time every day. Avoid skipping meals.
  • Having a starchy food at each meal. For example: whole grain breads, cereals, rice, pasta, and potato.
  • Choosing snacks that are high in protein. For example: skim cheese, mixed nuts.
  • Avoiding sugar and foods that are high in sugar. For example: jam, honey, regular soft drinks, and candy.
  • Choosing fresh fruits and vegetables daily. Choose canned fruits in juice only.
  • Choose fresh fruit instead of fruit juice most often.
  • Drinking sugar-free fluids when you are thirsty. For example: water, mineral water, sugar free soft drinks.

Weight Gain

Some people undergoing treatment for a brain tumour gain weight. Weight gain can be a result of eating too much or being less physically active. Some drugs may also cause you to put on weight.

If you want to lose weight, talk with your doctor or a registered dietitian before you start. Weight loss is stressful to your body. For many people, the best goal during treatment is to avoid putting on more weight. You can start losing weight after you have recovered from your treatment.

A weight loss diet needs to be balanced. It has to provide enough protein and other nutrients to rebuild strength and support the immune system.

  • Reduce the amount of fat you eat.
    • Avoid fried foods.
    • Remove skin from poultry.
    • Decrease use of butter, margarine, mayonnaise and salad dressings.
    • Choose low fat or skim dairy products.
    • Choose low fat snacks such as vegetables, low fat yogurt, popcorn and pretzels.
  • Choose fresh fruits instead of cakes, pies and pastries.
  • Try eating several smaller meals throughout the day.
  • Avoid skipping meals. This often leads to overeating later on.
  • Try to stay active and increase physical activity if you are able (e.g., take longer walks).

Changes in Taste

Your sense of taste can change during treatment. Some treatments that can alter the taste of foods are:

  • Radiation to the head
  • Some chemotherapy drugs
  • Antibiotics
  • Painkillers and other drugs

Your original sense of taste usually returns after treatment. To help deal with taste changes:

  • Rinse your mouth. Rinse your mouth before and after eating to clear your taste buds. Use Club Soda or stir 1 teaspoon of baking soda into 16 ounces (2 cups) of warm water.
  • Try different protein sources. Some people find that red meat has a bitter, metallic taste. Try chicken, dairy foods, peanut butter, eggs, tofu, fish, legumes, and nuts for other protein sources.
  • Use sour flavours. Sour foods may help overcome a metallic taste. Try adding lemons, citrus juices, and pickled foods to your meals. Do not add sour foods if you have a sore mouth or throat.
  • Use sugar. Add sugar to increase the taste of foods or decrease the salty or acid taste of other foods.
  • Eat cold foods. Serve foods at room temperature or colder to reduce strong tastes and smells.
  • Avoid metal implements. Try using plastic cutlery and glass cooking pots to reduce metallic tastes.
  • Enjoy cold fruit dishes. Fruit sorbet, sherbet, and fruit smoothies usually taste good.
  • Add flavour. If water tastes funny, add fresh mint leaves or lemon slices to flavour it.

​​​ Recipe

Try this refreshing and tasty recipe from the Goes Down Easy cookbook.

Orange, Avocado and Mango Salad


  • 3/4 cup orange juice
  • 2 tbsp honey
  • 1 tbsp olive oil
  • 1 tbsp minced fresh ginger


  • 5 cups torn mixed salad greens
  • 1 avocado, halved, pitted and thinly sliced
  • 1 mango, peeled, halved and thinly sliced
  • 2 large oranges, peeled and sectioned
  • 1 cup fresh raspberries or blueberries


  1. In small bowl, whisk together orange juice, honey, oil and ginger.
  2. In large bowl, toss greens lightly with some of the dressing (refrigerate any leftover dressing for another salad). Attractively arrange avocado, mango and orange slices on greens. Scatter berries on top.

Makes 4 servings. ​

Last reviewed: 9/28/2023
Last modified: 9/29/2023 12:36 PM
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