Weight changes can be common during cancer treatment. Some people gain weight, while others lose weight. Mostly, it is best to try to stay the same weight you were before you had cancer to help your strength, recovery and treatment.

  • There are a number of reasons you may put on weight during cancer treatment:
  • fatigue or tiredness is a common side effect of chemotherapy. This can lead to you being less active.
  • treatment may cause fluid retention (oedema) that can also increase your weight
  • chemotherapy can also cause menopause for some women. This means a lowered metabolism (the rate at which your body uses energy)
  • during treatment you may crave less healthy food
  • if you are having steroids as part of your treatment the side effects may include an increase in appetite and, longer term, can lead to a build-up of fatty tissue
  • hormone therapy involves medicines that lower the amount of oestrogen and/or progesterone in women, and testosterone in men. Changes in hormone levels can lead to increased fatty tissue, a reduction in muscle mass, and slower metabolism
  • people with cancer sometimes eat more to make themselves feel better during treatment. Over time, this can result in weight gain.
  • most treatment can mean you are less active than usual over a longer period of time, often causing weight gain.

Losing weight is not easy and can take time. Don’t be hard on yourself - try to set realistic goals through healthy eating and keeping active.

Get family/whānau and friends to support you.

Tips for losing weight

Talk to your treatment team about safe ways to lose weight. Avoid fad diets or medications promising rapid weight loss. You’re more likely to keep weight off if you lose it slowly and steadily.

Things you can do include:

  • Follow the healthy eating tips
  • Try to have smaller meals - use a smaller plate and avoid going back for seconds.
    Choose whole grain bread, pasta and cereals – these contain increased fibre which can make you feel fuller for longer.
  • Try to eat plenty of fruit and vegetables which are filling but not too high in calories.
  • Limit fat, sugar, and white flour. Swap biscuits, cakes and sweets for unsweetened and unsalted options. Snack on fruit and vegetable sticks rather than biscuits, cake and sweets.
  • Drink water instead of soft drinks, and unsweetened tea or coffee with low fat milk.
  • Avoid or limit alcohol as it is high in calories.
  • Try healthier ways of cooking such as steaming or BBQ instead of frying.
  • Limit the amount of takeaways you eat as they are usually high in fat and salt.
  • Increase your activity – always start slowly and build up gradually.

If you are concerned about your weight gain, speak to your treatment team for help in managing this.

Call your doctor if you experience any of the following signs of fluid retention:

  • if your skin feels stiff or small indents are left after pressing on the swollen area
  • if you have swelling in your arms or legs, especially around the ankles and wrists
  • if rings, watches, bracelets, or shoes are tighter than usual
  • if your hands, elbows, wrists, fingers, or legs are less easy to move.

Managing changes in your weight

Weight changes can be common during cancer treatment. Some people gain weight, while others lose weight. Mostly, it is best to try to stay the same weight you were before you had cancer to help your strength, recovery and treatment.

Weight gain

Some people gain weight due to some chemotherapy medications, steroids, hormone therapy, being less active, eating more and/or retaining fluid.

A small increase in weight is not usually a problem. But a large weight gain can affect your general health. It can increase your blood pressure and your risk of developing diabetes and heart problems. Weight increases can affect how you feel about yourself, your confidence, and energy levels.

Last updated: July 26, 2021