Managing Weight Gain During Cancer Treatment

This page is for people who are gaining weight during cancer treatment. It explains the common causes, when gain may be fluid, and what tends to help.

Gaining weight during treatment can feel confusing. It is not a sign of poor effort. ACS says weight gain happens most often in people with breast, prostate or ovarian cancer who get certain medicines, hormone therapy or specific chemotherapy regimens. Several causes can act together.

ACS says steroid medicines can increase appetite and cause fat to build up in areas such as the belly and face. Fluid retention is another possible cause of weight gain. Ask your team what to expect from your medicines.

NCI says hormone therapy can cause weight gain and fluid retention (edema). ACS adds that it affects how the body uses calories and can lower muscle while raising fat. Some treatments cause menopause, which also slows metabolism. These are physical changes, not a matter of willpower.

ACS says treatment can cause fatigue, which makes it harder to be active. It can also trigger food cravings and lower your metabolism so you burn fewer calories.

ACS says fluid retention from cancer and its treatment can cause swelling, such as edema, lymphedema or ascites (fluid in the abdomen). Fluid can show up as weight on the scale. The section at the end of this page says when to call.

ACS suggests working with a registered dietitian on a personal eating plan. It also suggests choosing nutrient-dense, lower-calorie foods such as vegetables and lean protein, and limiting sugary drinks. Your team may suggest limiting salt. Ask your team before you increase activity.

NCI notes that people with cancer may need more protein and calories to keep up their strength during treatment. So talk to your team before you cut back on food.

Steroids can raise appetite. Hormone therapy can change how your body uses calories. Fatigue is a treatment effect, not laziness. If someone implies otherwise, you can name what you are taking and ask for practical support.

• Call 911 or go to an emergency department if you are struggling to breathe at rest, cannot lie flat without gasping, or become confused. Do not drive yourself.
• Call your care team the same day if the scale climbs more than five pounds in a week, or if your ankles, legs, hands, or abdomen puff up. ACS lists gaining more than 5 pounds in a week as a reason to tell your team. Swelling can mean retained fluid.
• Call your care team within a day or two if one arm or leg swells on its own after lymph node surgery or radiation, or if your abdomen feels tight and distended. Lymphedema and ascites need to be assessed by your team.

• American Cancer Society: Weight Changes
• NCI: Nutrition in Cancer Care (PDQ)