​​​Some people gain weight during cancer treatment. Gaining a little weight during cancer treatment is normally not a problem. However, gaining a lot of weight may affect your health and well-being. Weight gain can also affect how quickly you recover after cancer.



  • The cancer itself.
  • Some types of cancer treatment.
  • Medicine used to help manage side effects.
  • Side effects like fatigue. Fatigue may cause cancer survivors to be less active.


What you can do

If you are worried about your weight gain, talk to your doctor or a registered dietitian. Do this before starting a diet or changing your eating habits. Your doctor can help find out the possible cause of the weight gain. Your doctor and dietitian can also help you find the best way to manage it. A dietitian can provide nutrition guidelines or a diet plan tailored to your needs.

You can attend classes on healthy eating or exercise, or view the healthy eating classes online. For more information about healthy eating classes or exercise classes, see the Princess Margaret’s calendar of events. See the Princess Margaret Calendar of Events »​


More information


Last reviewed: 1/4/2018
Last modified: 9/26/2023 12:19 PM
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