The Link Between Obesity and Cancer

Last Updated: March 23, 2021

Dr. Jennifer Ligibel talks about the link between obesity and cancer, including steps survivors can take to improve their health and manage their weight.

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Obesity and Cancer 


Cancer.Net®: Doctor-Approved Patient Information from ASCO®

The Link between Obesity and Cancer

Jennifer A. Ligibel, MD: Over the last few years we’ve learned a lot about the links between obesity and both the risk of developing and dying from cancer.  Although many people don’t recognize this, being obese is a significant risk factor for developing many common cancers.

More Recently there’s also been data that shows that people who are obese when they’re diagnosed with cancer, especially with cancers like breast cancer and prostate cancer, also seem to have a higher risk of developing a recurrence and dying from their disease.

Although we don’t know for sure whether modifying weight after diagnosis will have an effect, knowing that there’s a link between obesity and cancer is important in oncology.

Managing Your Weight After a Cancer Diagnosis

Dr. Ligibel:  It’s important for cancer patients to be aware that they may gain weight during their therapy and so that there’s not a need to try to consume extra food to prevent this weight gain.  It’s also important for providers to give people information about healthy eating behaviors during and after cancer therapy.  Many patients turn attention after completing their active cancer treatment to survivorship.  And this often can include a focus on healthy eating, losing weight, and increased physical activity.

We also know that it’s safe for most cancer patients to exercise all through their cancer trajectory.  Remaining more physically active has been shown to help prevent people from gaining weight during cancer therapy.  And so we encourage patients to be active during all parts of their cancer care.

We all know that we should exercise more, eat more healthfully, and weigh less.  This may be especially challenging for cancer survivors.  After going through months of rigorous therapy with chemotherapy, radiation, and surgery, many patients are fatigued.  And fatigue can make it difficult to initiate a new program and especially to be more physically active.

Cancer survivors may also be left with long-term toxicities of their therapy.  Things like neuropathy can make it very difficult to exercise more.  Patients may also be left with psychological impacts of their cancer treatment and diagnosis.  Patients may feel less comfortable wearing exercise clothing or being active in a gym setting.  These things are all important to keep in consideration when a cancer survivor or a person undergoing therapy thinks about how they can make healthy lifestyle changes.

Setting Your Weight Management Goals

Dr. Ligibel: Patients also can have a change in their metabolism during therapy, and this is especially true for young women who go through menopause as a result of either chemotherapy or other cancer treatments.  Weight gain can be very significant in this group of patients.  Other individuals may receive steroids or other medications as part of their cancer therapy that can contribute to weight gain.  Other patients will gain weight for reasons that we’re not completely certain, but in many diseases like breast cancer, weight gains of 5 to 10 pounds after diagnosis are seen very frequently and can be a problem that people struggle with for years after their cancer treatment

It’s very important to start with manageable goals.  If you’re a person who’s not been exercising for more than a year, it’s probably not realistic to sign up for a marathon.  You want to start slow with measurable goals.  Walk around the block twice a day.  Build up your strength gradually.  Make manageable changes in your dietary patterns.  Set goals that you can achieve and that will make you feel good, but focus on the fact that you want to make these healthy lifestyle changes and that this is something that will help build your strength and make you more healthful in the years to come.

 Where to get more Information?

Dr. Ligibel: As an oncologist, I know that my patients come to me frequently with many questions about physical activity, diet, weight management strategies.  There’s a lot of information and misinformation about these topics that’s available on the internet, through books.  Based on this, ASCO felt it was very important to develop materials that were evaluated by medical oncologists and other specialists to provide patients with evidence-based recommendations for weight management, diet, and physical activity suggestions after cancer diagnosis.  And these materials can be found on, along with a lot of other information about cancer diagnosis and treatment.

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Cancer.Net®: Doctor-Approved Patient Information from ASCO®

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