Metastatic Breast Cancer: What Can I Do About Weight Gain?

by Amy Hendel, P.A. Health Writer

Cancer and its treatments may cause weight loss, weight gain, and weight fluctuations. Some of the weight changes come from amped-up hunger or suppressed appetite from the cancer‘s direct impact and from medications. If you have metastatic breast cancer (MBC), some medications seem to especially instigate weight gain. Weight loss can be beneficial if you were overweight or diagnosed with obesity prior to treatment or if you gain weight after treatment. Obesity can drive cancer, so weight gain should be addressed.

Cancer patient undergoing chemotherapy treatment.

What is really driving the weight gain?

Research published in the World Journal of Clinical Oncology found that weight gain occurs in most women after breast cancer treatment. Younger women, those closest to ideal weight, and those receiving chemotherapy are at highest risk. Weight gain is usually about 2-11 pounds and is linked to body composition changes — like increased fat mass and loss of lean mass. Chemotherapy can also drive early menopause and associated weight gain. Hormone therapy is also associated with weight gain.

Woman checking her weight on a scale.

Kinds of weight gain

Drugs like steroids can cause weight gain due to hunger, but they can also cause you to bloat due to water retention. If that’s the case, monitoring your sodium intake can help limit excess fluid retention. If you’re over-eating due to medication, or packing on fat pounds, then you do want to intercept that type of weight gain. Excess fat can drive the spread of breast cancer (and ovarian, colon, kidney, liver, pancreatic, gallbladder, endometrial cancer), so you want to limit that influence.

Woman struggling with pain from inflammation.

At the crossroads of obesity, inflammation and immune function

It’s important to understand that obesity drives low-grade inflammation, and this inflammation impairs immune response and is also linked to several diseases, including cancer. In the case of breast cancers, excess fat, in combination with menopause can drive triple-negative breast cancer. This type of breast cancer is aggressive (metastatic) and poorly responsive to treatment. In the presence of MBC, the goal should be to lose weight if you are overweight or obese.

Woman working out on a rowing machine at the gym.

Lifestyle changes for MBC

Lifestyle changes involve diet, exercise, stress reduction, and sleep behaviors. If the goal is weight loss, tailor your plan to the other treatments you receive, since there will likely be appetite fluctuations and days where you feel energized and days or possibly fatigued. Any program you set up should factor in your age, the impact of drugs, radiation, and surgery. Consider working with a dietician and personal trainer experienced with handling MBC. Clear diet and exercise with your doctor.

Woman in the kitchen preparing a healthy meal.

Diet and nutrition: Part 1

A professional can help you with weight loss goals. Address medication side effects like weight gain and bloat with your oncologist. In terms of basic diet strategies, foods you should avoid include: frequent red meat meals (and charred meats), full fat dairy foods (milk, cheeses), food heavy in saturated fat, highly processed foods, alcohol, and sugary drinks. Then aim for balance. Emphasize fruits and vegetables and try to meet eight to 10 servings combined daily. Choose whole fruits, not juice.

Healthy tofu stir fry.

Diet and nutrition: Part 2

Aim to eat lean and mostly plant-based proteins: skinless chicken and turkey, eggs and egg whites, beans, nuts, seeds and legumes, tofu, tempeh, low fat Greek yogurt, and bean-based pastas. Choose wild fish and cook simply. Try heart-healthy fats: unprocessed nuts and nut butters, olive oil, and avocado. Limit coconut oil use. As for soy, less processed (edamame beans, tofu) is better, and aim for no more than 3 servings daily. Check with your doctor regarding soy consumption.

Whole wheat pasta with vegetables.

Let's talk about carbs

Assuming that you’ve discussed daily calorie needs with a professional, especially if weight loss is a goal, then the spotlight needs to be on grains. This food group needs special attention because processed carbohydrates have overwhelmed the American diet. Choose whole grains as the primary ingredient and make sure the ingredient list is short. Labels should say 100 percent whole wheat or the unprocessed grain should be the first and primary ingredient. Use portion control and decide how many portions to have daily.

Group of breast cancer survivors jogging.

Best exercises: Part 1

Diet and exercise goals should include losing excess fat or maintaining weight and preserving or building lean muscle. Add building strength as a specific achievement. If you have any arm movement issues or swelling post-mastectomy, then improved range-of-motion should also be an important focus. Aerobic exercise will help to burn calories — try walking hills, speed walking, swimming. Increase intensity and duration over time and cross train to stay challenged. Consider fun classes like Zumba.

Exercising with resistance bands.

Best exercises: Part 2

Resistance training builds muscle. Start with light weights and consider using elastic bands, which come in a variety of resistances. Insurance may cover workouts with a physical therapist. If so, as you wrap up that relationship, make sure you create some programs you can follow on your own. Find out if there are MBC-specific exercise and wellness programs close by or at a local hospital. For example, the JCC Manhattan in conjunction with Mount Sinai and BreastLink New York has a robust program.

Woman meditating to minimize stress.

Recognize stress and manage it

Chronic stress is linked to low level general inflammation, so it’s important to be aware of your stress levels and to address them. Adding yoga or tai chi can help to lower stress, as can meditation. The key here is to identify stressors: Is it financial stress, unrelenting concern that your illness may result in you losing your job, or fear of the unknown future? Some of the issues may not have ready solutions, but there are techniques to manage stress. Attending a support group can help too.

Woman sleeping comfortably.

Get your ZZZs

Research continues to find links between lack of adequate, restful, consistent sleep and optimal health and weight gain. Studies show MBC causes sleep disturbance, especially if there is bone metastatic disease, depression, or lack of social support. A 2015 article by the Society for Women’s Health Research identified poor quality sleep as a silent source of disability in breast cancer. Cancer-related fatigue can also cause sleep disturbance. Talk to your doctor about sleep issues.

Women explaining something to a friend.

Handling the well-intentioned 'negative' weight comments

Your loved ones are concerned about your health. Even the most well-intentioned person can sometimes put their foot in their mouth and say the wrong thing. “You’re gaining weight and that’s a good thing, right?” Or, “Is that bloat or are you gaining a lot of weight?” Or, “It looks like we can have fun and go shopping for new clothes, right?” Be honest and let them know if those comments hurt: “I know you mean well, but my weight is a real struggle.” Yet, recognize they love you and are worried.

Group of joyous breast cancer survivors.

Continue to live, continue to thrive

There’s a saying in medicine: “Your condition does not define you.” You are living with MBC, and that may mean some difficult, even brutal treatment and recovery periods. Following the recommendations in this slideshow can help you prioritize certain behaviors that require daily commitment. You should feel encouraged to embrace these habits at whatever pace feels comfortable. Value support and ask for it. Find a buddy or group who can share your journey to protect and improve your health.

Amy Hendel, P.A.
Meet Our Writer
Amy Hendel, P.A.

Known as "The HealthGal", Amy Hendel P.A. is a medical and lifestyle reporter, nutrition and fitness expert, health coach and brand ambassador. Trained as a physician assistant, she maintains a health coach private practice in New York and Los Angeles. Author of The Four Habits of Healthy Families, find her on Twitter @Healthgal1103 and on Facebook @TheHealthGal. Check “Daily Health News” at Her personal mantra? “Fix it first with food, fitness, and lifestyle.”