Adapt your diet after diagnosis

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Adapt your diet after diagnosis

Your treatments may cause unpleasant side effects such as loss of appetite, weight change, even nausea. Good nutrition is one of the best strategies for maintaining a better quality of life during and after treatment. Find out why, and how to make food an ally in your fight against the disease!

Combat fatigue

Fatigue from breast cancer treatment is not the same as normal fatigue. Normal fatigue is more likely to be short-lived and easily resolved with rest. Treatment-related fatigue, on the other hand, lasts for a long time and because it is not the result of too much physical effort or lack of rest, sleeping will not be enough to alleviate it1.

Food is an important source of fuel for the body, so a poor diet can be a factor in making you feel more fatigued during your breast cancer treatment. Eating well, along with being physically active, can be an important part of your treatment management.

It is advisable to eat three meals and two to three snacks a day, consume a wide variety of foods and drink plenty of fluids during the day to stay well hydrated. Do not hesitate to speak to your medical team if you have any questions or concerns, as they may be able to refer you to a nutritionist to help you in your process.

Adapt your diet after diagnosis

Help your immune system

A protein-rich diet during treatment can help you maintain a good energy level, boosting your immune system as it does its job. The good news is that protein is easy to include in your diet, since it is found in meat, fish, poultry, cheese, milk and yogurt. Because it is also present in seeds and nuts, it is easy to get in your snacks too. The main thing is to vary your sources of protein2.

Keep your bones healthy

Among the common side effects of treatment is osteoporosis, a deterioration of the bones. Bone is a living tissue that is constantly breaking down and rebuilding. Treatments can damage bones, making them more “porous,” which increases the risk of fracture. However, there are ways to reduce this risk, including proper nutrition. Learn more through the Breast & Bone Health program created by Dr. Carmen Loiselle and her team and funded by our Foundation. It offers fact sheets with tips and tools for good bone health. Discover the one on the benefits of a diet rich in calcium and vitamin D, as well as the foods to include in your diet.

Be careful! If you think you might be lacking calcium, vitamin D or any other nutrients in your diet, consult your medical team before taking any supplements in concentrate form. It is important to learn about the effects and safety of these products before using them.

Adapt your diet after diagnosis

Avoid risking infections or complications

As mentioned, the immune system can be weakened during treatment. Therefore, it is also important to take precautions during this period to avoid the risk of infections or complications. For example3:

  • Wash your fruit and vegetables well before eating them;
  • Cook your meat thoroughly;
  • Avoid sushi and tartar-type meals;
  • Avoid raw cheeses or cheeses made from unpasteurized milk;
  • Avoid raw eggs;
  • Avoid alcohol, which can reduce the effectiveness of treatments;
  • Avoid supplements or soy protein tablets (concentrate);
  • The effect of these products on the body is not yet well known4.

If in doubt, always ask your medical team whether or not a food is compatible with your treatments.

Limit some adverse effects

There are a few tips that can help you limit the side effects of treatment, such as loss of appetite, while maintaining a healthy diet:

  • Eat less, but often: opt for several small portions of a variety of foods throughout the day;
  • Every bite counts: make sure you get as many nutrients as possible in each mouthful;
  • Drink plenty, in small amounts throughout the day;
  • Avoid drinking just before meals, as this may suppress your appetite even more;
  • Avoid high-fat, sweet or very salty foods;
  • Take your time when eating and listen to your body;

Get moving! Physical activity makes you hungry, and you will feel ready to enjoy a good meal. Following these few tips will ensure that you have a healthy and appropriate diet during your breast cancer treatment. Remember to always confirm with your medical team what is right for you, as every cancer is different! We know that this time of year can bring about changes to your body and perhaps to your eating habits, so please be kind to yourself and don’t put too much pressure on yourself.


  1. « Comprendre et gérer la fatigue liée au cancer | CHU de Québec-Université Laval ».
  2. « Introduction aux protéines et aux aliments riches en protéines – Unlock Food ».
  3. « Chimiothérapie | CHU de Québec-Université Laval ».
  4. « Nutrition_FR_0218-small.pdf ».