​​By Sarah Buchanan RD, Clinical Dietitian, Princess Margaret Cancer Centre

Diarrhea is a common side effect of cancer treatment. It can be caused by chemotherapy, radiation, surgery that affects the digestive tract, or medications such as antibiotics.

Being mindful of the foods you eat can help you manage diarrhea. Choose foods that are low in fibre, lactose, and fat.

  • Eating insoluble fibre can make diarrhea worse so it is best to avoid this type of fibre. Insoluble fibre is found in the skins of fruits and vegetables, whole grain products and nuts and seeds.
  • Lactose is a natural sugar found in milk products. When people are experiencing diarrhea, the body may have difficulty digesting lactose which can make a person's symptoms worse.
  • Higher fat foods such as French fries and doughnuts because they are more difficult to digest when you have diarrhea and may worsen your symptoms.

Below is a recipe for banana bread that is low in fibre, lactose, and fat. Banana bread is a good snack option if you have diarrhea. ​

​​​ Banana Bread

Recipe makes 1 loaf, 12 slices
Per slice: cal 162, pro 3g, fat 5g, carb 26g, fibre 1g


Amount (Imperial) Ingredient Amount (Metric)
1 cup Mashed ripe bananas (2 medium) 250mL
1 tsp Baking soda 5 mL
½ cup Plain low fat yogurt 125 mL
¼ cup Vegetable oil 50 mL
½ cup Brown sugar 125 mL
1 Egg, beaten 1
1 tsp Vanilla 5 mL
1 ½ cups All-purpose flour 375 mL
1 tsp Baking powder 5 mL
Pinch Salt Pinch


  1. In small bowl combine bananas, baking soda, and yogurt. Set aside. In large bowl combine oil sugar, egg and vanilla, blend well. Add banana mixture and blend.
  2. In small bowl stir together flour, baking powder, and salt. Add to banana mixture and stir until just moistened.
  3. Spread batter into a lightly oiled 8- x 4-inch (1.5L) loaf pan. Bake in preheated 350F (180C) oven for 50 to 60 minutes or until loaf springs back when gently touched.
  4. Let cool in pan on rack for 15 minutes. Turn onto rack; let cool completely.

Recipe from Goes Down Easy: Recipes to help you cope with the challenge of eating during cancer treatment. Find this book, available for borrowing, in the Princess Margaret Patient & Family Library.

For nutrition information for diarrhea, read the electronic pamphlet Eating Hints for People with Diarrhea [PDF, opens in new window]. You can also pick up a hard copy version of the pamphlet from the Patient and Family Library. ​


Last reviewed: 9/28/2023
Last modified: 11/2/2023 9:19 AM
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