You may lose or gain weight for various reasons, including the effects of the cancer and cancer treatment.
If you are underweight or losing weight you may need to include more protein and more energy in your diet. Good sources of protein and energy (calories or kilojoules) include: meat, fish, poultry, milk, and dairy products, eggs, legumes (e.g. baked beans, chick peas, lentils) and nuts. For extra protein, aim to include at least one higher protein food at each meal. High protein foods and drinks shouldalso be included as between–meal snacks. Nutritional supplements such as nourishing drinks may also be useful to help you gain weight.
You may also be encouraged to eat foods that are typically not considered as healthy foods as they can be high in fat and sugar. Including foods with extra protein, fat and sugar in your diet, for most people, will be for a relatively short period of time. If you have any concerns, discuss them with your doctor or dietitian.
Weight gain can happen for various reasons. People with certain types of cancer, especially those with breast cancer, are more likely to gain weight during and after treatment.
Certain types of chemotherapy, hormone therapy and some medicines such as steroids can cause weight gain. These treatments can also cause your body to retain water, which can make you feel puffy and gain weight, or some treatments can increase your appetite so you feel hungry and eat more. Being tired because of the treatment may lead to decrease in activity. Being less active can also cause weight gain.
Generally, during cancer treatment is not a good time to deliberately lose weight. Try to maintain your weight throughout treatment. If you gain weight during treatment and are concerned, speak first to your doctor about it to work out how to best manage it. In situations where you have lost weight without trying, regaining at least some of this weight can help you better tolerate treatment.