Why is managing body weight important?

Connections to cancer survival

Our note: The link between weight loss and risk of death is a little tricky to interpret. As disease progresses, people tend to lose weight, and especially as they approach the end of life. We often cannot determine whether weight loss was a cause or a consequence of illness and approaching death. Only if weight loss is associated with longer survival can we be confident that weight loss may be helpful.

Cancer as a whole

Modest evidencesignificant effects in at least three small but well-designed randomized controlled trials (RCTs), or one or more well-designed, mid-sized clinical studies of reasonably good quality (RCTs or observational studies), or several small studies aggregated into a meta-analysis (this is the CancerChoices definition; other researchers and studies may define this differently) of a less effective response to chemotherapy among obese people

Advanced cancer

Preliminary evidencesignificant effects in small or poorly designed clinical studies OR conflicting results in adequate studies but a preponderance of evidence of an effect (this is the CancerChoices definition; other researchers and studies may define this differently) of a link between earlier cancer relapse and fatigue and weight loss among people with metastatic colorectal cancer

Brain cancer

Modest evidence of worse survival among people with high-grade glioma who were either underweight (BMI less than 18.5) or obese (BMI more than 30); opposite impacts of body weight are seen with glioblastoma multiforme as noted below in Better survival with increased body weight

Breast cancer

Modest evidence of worse prognosis and survival among people who are obese or those who either gained or lost more than 10% of their body weight, but mostly among people diagnosed with breast cancer after menopause

Colorectal cancer

Modest evidence of a poorer prognosis or colorectal cancer survival among people who are obese, especially more than three years after diagnosis

Better survival with increased body weight

Some types of cancer show better survival among people with higher body weights.

Modest evidence of better survival among overweight or obese people with advanced melanoma, non-small cell lung cancer, renal cell carcinoma, and other types of advanced cancer treated with immune checkpoint inhibitor therapy or targeted therapy

Connections to body terrain factors

These body terrainthe internal conditions of your body, including nutritional status, fitness, blood sugar balance, hormone balance, inflammation, and more factors are linked to cancer risk or outcomes.

High blood sugar and insulin resistance

Modest evidencesignificant effects in at least three small but well-designed randomized controlled trials (RCTs), or one or more well-designed, mid-sized clinical studies of reasonably good quality (RCTs or observational studies), or several small studies aggregated into a meta-analysis (this is the CancerChoices definition; other researchers and studies may define this differently) of better blood sugar and insulin sensitivity among people losing weight

Preliminary evidencesignificant effects in small or poorly designed clinical studies OR conflicting results in adequate studies but a preponderance of evidence of an effect (this is the CancerChoices definition; other researchers and studies may define this differently) of more weight loss among obese people who reduced high blood sugar levels

Hormone balance

Obesity is linked to hormone imbalances.

Immune function

Obesity affects immune cell function.

Inflammation

Good evidencesignificant effects in one large or several mid-sized and well-designed clinical studies (randomized controlled trials (RCTs) with an appropriate placebo or other strong comparison control or observational studies that control for confounds) (this is the CancerChoices definition; other researchers and studies may define this differently) of a link between obesity and inflammation

Modest evidence of less inflammation among people losing excess weight

Oxidative stress

Obesity is linked to oxidative stressan imbalance between free radicals and antioxidants in your body; this imbalance can cause harmful oxidation reactions in your body chemistry.

Your microbiome

Modest evidence of worse microbial balance among people who are obese and of improved balance among people losing weight

Vitamin D levels

Modest evidence of a link between low vitamin D levels and high body mass index

Telomere length

Good evidence of shorter telomerea ‘cap’ at the end of each strand of DNA that protects chromosomes; telomeres become shorter with each cell replication, eventually becoming too short, causing cells to age and die a normal cell death (apoptosis) length among people with higher body mass index

Connections to symptoms and side effects

Cognitive difficulties

Preliminary evidencesignificant effects in small or poorly designed clinical studies OR conflicting results in adequate studies but a preponderance of evidence of an effect (this is the CancerChoices definition; other researchers and studies may define this differently) of bigger improvements in cognitive scores among women with breast cancer with the highest baseline BMIs participating in a weight-loss intervention

Depression

Preliminary evidence of a link between a large waist-to-hip ratio and depression among middle-aged women

Lymphedema

Modest evidencesignificant effects in at least three small but well-designed randomized controlled trials (RCTs), or one or more well-designed, mid-sized clinical studies of reasonably good quality (RCTs or observational studies), or several small studies aggregated into a meta-analysis (this is the CancerChoices definition; other researchers and studies may define this differently) of higher risk of lymphedema among people with breast cancer who are obese

Other side effects and symptoms

Good evidencesignificant effects in one large or several mid-sized and well-designed clinical studies (randomized controlled trials (RCTs) with an appropriate placebo or other strong comparison control or observational studies that control for confounds) (this is the CancerChoices definition; other researchers and studies may define this differently) of longer surgery times, higher illness (morbidity) after surgery, and higher rates of conversion from laparoscopic to open surgery among people who are obese

Good evidence of higher risk of infection and other complications related to surgery among people who are obese

Modest evidence of higher risk of surgical site infection among people who are obese

Good evidence of higher risks of cardiovascular complications after surgery among people with excess body weight

Good evidence of substantially higher risk of blood clots after surgery among women with body mass index (BMI) of 25 or higher

Symptoms not specific to cancer

Good evidence of a link between obesity and anxiety

Preliminary evidence of a link between a large waist-to-hip ratio and depression among middle-aged women

Modest evidence of higher risk of pain (not specific to cancer) among people with obesity and less pain among those losing weight

No evidence of an effectoverall, one or more studies did not demonstrate that a treatment or intervention led to an expected outcome; this does not always mean that there is no effect in clinical practice, but that the studies may have been underpowered (too few participants) or poorly designed. Larger, well-designed studies provide more confidence in making assessments. of moderate weight loss (about 8 pounds) on self-reported stress among adults with excess weight or obesity in a combined analysis of studies

Connections to cancer risk

Excess body weight is associated with an increased risk for cancer related to at least 13 sites:60Avgerinos KI, Spyrou N, Mantzoros CS, Dalamaga M. Obesity and cancer risk: emerging biological mechanisms and perspectives. Metabolism. 2018 Nov 13. pii: S0026-0495(18)30232-4; National Cancer Institute. Obesity and Cancer. January 17, 2017. Viewed September 22, 2021.

  • Breast cancer (postmenopausal)
  • Colorectal cancer
  • Esophageal cancer
  • Gallbladder cancer
  • Kidney cancer
  • Liver cancer
  • Meningioma
  • Multiple myeloma
  • Ovarian cancer
  • Pancreatic cancer
  • Stomach (gastric cardia) cancer
  • Thyroid cancer
  • Uterine (endometrial) cancer

A few further cancer types show a possible association:

  • Breast cancer in males
  • Non-Hodgkin’s lymphoma
  • Oral cancers
  • Prostate cancer (aggressive)
Breast cancer

Good evidencesignificant effects in one large or several mid-sized and well-designed clinical studies (randomized controlled trials (RCTs) with an appropriate placebo or other strong comparison control or observational studies that control for confounds) (this is the CancerChoices definition; other researchers and studies may define this differently) of higher risk of breast cancer or second primary cancer among people with excess body weight (BMI) except regarding young-adult weight

Modest evidencesignificant effects in at least three small but well-designed randomized controlled trials (RCTs), or one or more well-designed, mid-sized clinical studies of reasonably good quality (RCTs or observational studies), or several small studies aggregated into a meta-analysis (this is the CancerChoices definition; other researchers and studies may define this differently) of lower risk of breast cancer among women 50 years and older sustaining a loss of more than 4.4 pounds of body weight, with more benefit among women losing more weight

Colorectal cancer

Good evidence of moderately higher risk of colorectal cancer among people with excess body weight, especially among men

Gastrointestinal cancer

Esophageal cancer: good evidence of higher risk of esophageal squamous cell carcinomas but not adenocarcinomas among people with higher body mass index

Gallbladder cancer: good evidence of moderately higher risk of gallbladder cancer among people with excess body weight

Ovarian cancer

Good evidence of a small increase in risk of ovarian cancer among people with excess body weight, with higher risk as weight increases

Pancreatic cancer

Good evidence of higher pancreatic cancer mortality among people without cancer at baseline with higher body mass index

Prostate cancer

Preliminary evidencesignificant effects in small or poorly designed clinical studies OR conflicting results in adequate studies but a preponderance of evidence of an effect (this is the CancerChoices definition; other researchers and studies may define this differently) of a much larger risk—almost double—of prostate cancer recurrence among people with weight gain after diagnosis

Thyroid cancer

Good evidence of higher risk of thyroid cancer among people with higher body mass index

How a healthy body weight relates to other practices and habits

Healthy lifestyle

Lower risk of lethal prostate cancer, but not overall prostate cancer, over 27 years among people with high genetic risk following a healthy lifestyle of a healthy weight, vigorous physical activity, no smoking, and a healthy diet (good evidence)

Eating Well

Not specific to cancer:

  • More weight loss and less weight gain among people with body-mass index (BMI) higher than 25 eating more fruits and vegetables (good evidence)
  • Lower body weight or more weight loss among people eating earlier instead of late in the day (modest evidence)
  • No evidence of an effect on obesity among people eating high-calorie (energy-dense) foods in a combined analysis of reviews and combined analyses

Moving More

Less body fat and more lean body mass among people with cancer participating in exercise without regard to treatment phase (strong evidence)

Increased lean body mass and less body fat or obesity during neoadjuvant or adjuvant chemotherapy, radiotherapy, or hormone therapy, including androgen deprivation therapy, among people participating in exercise (good evidence)

Sleeping Well

Not specific to cancer:

  • Moderately higher risk of obesity among people with sleep duration less than 6 hours (good evidence)
  • Higher risk of obesity among people with sleep duration more than 7 hours (modest evidence)
  • Lower sleep disturbance scores among sedentary obese or overweight people losing weight or abdominal fat compared to no loss in a small observational study81Nam S, Stewart KJ, Dobrosielski DA. Lifestyle intervention for sleep disturbances among overweight or obese individuals. Behavioral Sleep Medicine. 2016;14(3):343-50. (preliminary evidence)

Creating a Healing Environment

Not specific to cancer:

  • Greater risk of obesity and larger waist circumference among people with the highest body levels of bisphenol A (BPA) (modest evidence)
  • Lower risk of overweight and obesity among people without cancer consuming organic foods more frequently (modest evidence)

Sharing Love and Support

Not specific to cancer:

  • More abdominal fat among women with lower levels of perceived social support (preliminary evidence)

Resource

Authors

Nancy Hepp, MS

Lead Researcher and Program Manager
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Ms. Hepp is a researcher and communicator who has been writing and editing educational content on varied health topics for more than 20 years. She serves as lead researcher, program manager, and writer for CancerChoices. Her graduate work in research and cognitive psychology, her master’s degree in instructional design, and her certificate in web design have all guided her in writing and presenting information for a wide variety of audiences and uses. Nancy’s service as faculty development coordinator in the Department of Family Medicine at Wright State University also provided experience in medical research, plus insights into medical education and medical care from the professional’s perspective.

Nancy Hepp, MS Lead Researcher and Program Manager

Laura Pole, RN, MSN, OCNS

Senior Clinical Consultant
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Laura Pole is senior clinical consultant for CancerChoices. Laura is an oncology clinical nurse specialist who has been providing integrative oncology clinical care, navigation, consultation, and education services for over 40 years. She is the co-creator and co-coordinator of the Integrative Oncology Navigation Training at Smith Center for Healing and the Arts in Washington, DC. Laura also manages the “Media Watch Cancer News That You Can Use” listserv for Smith Center/Commonweal. In her role as a palliative care educator and consultant, Laura has served as statewide Respecting Choices Faculty for the Virginia POST (Physician Orders for Scope of Treatment) Collaborative as well as provided statewide professional education on palliative and end-of-life care for the Virginia Association for Hospices and Palliative Care.

For CancerChoices, Laura curates content and research, networks with clinical and organizational partners, brings awareness and education of integrative oncology at professional and patient conferences and programs, and translates research into information relevant to the patient experience as well as clinical practice.

Laura sees her work with CancerChoices as a perfect alignment of all her passions, knowledge and skills in integrative oncology care. She is honored to serve you.

Laura Pole, RN, MSN, OCNS Senior Clinical Consultant

Reviewer

Miki Scheidel

Co-Founder and Creative Director
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Miki Scheidel is Co-founder and creative director of CancerChoices. She led the effort to transform Beyond Conventional Cancer Therapies, the prior version of CancerChoices, to its current form. Miki and her family were deeply affected by her father’s transformative experience with integrative approaches to metastatic kidney cancer. That experience inspires her work as president of the Scheidel Foundation and as volunteer staff at CancerChoices. She previously worked with the US Agency for International Development and Family Health International among other roles. She received her graduate degree in international development from Georgetown University, a graduate certificate in nonprofit management from George Mason University, and a Bachelor of Arts from Gettysburg College.

Miki Scheidel Co-Founder and Creative Director

Last update: January 27, 2023

Last full literature review: August 2021

CancerChoices provides information about integrativein cancer care, a patient-centered approach combining the best of conventional care, self care, and evidence-informed complementary care in an integrated plan cancer care. We review complementaryin cancer care, complementary care involves the use of therapies intended to enhance or add to standard conventional treatments; examples include supplements, mind-body approaches such as yoga or psychosocialtherapy, and acupuncture therapies and self carelifestyle actions and behaviors that may impact cancer outcomes; examples include eating health-promoting foods, limiting alcohol, increasing physical activity, and managing stress practices to help patients and professionals explore and integrate the best combination of conventionalthe cancer care offered by conventionally trained physicians and most hospitals; examples are chemotherapy, surgery, and radiotherapy and complementary therapies and practices for each person.

Our staff have no financial conflicts of interest to declare. We receive no funds from any manufacturers or retailers gaining financial profit by promoting or discouraging therapies mentioned on this site.

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