Ketogenic diets are high in fat, moderate in protein and low in carbohydrates, with weak to preliminary evidence of anticancer effects, relief of side effects, and benefits on your body terrainthe internal conditions of your body, including nutritional status, fitness, blood sugar balance, hormone balance, inflammation and more.

Safety and precautions

A ketogenic diet (KD) is a complex diet to follow and may cause side effects, some of which may be serious: weight loss, nutrient deficiencies, and more. Unless weight loss is desirable, this could be a concern. “As cancer patients are particularly susceptible to clinically significant malnutrition in the form of weight loss from both fat and muscle mass, this side effect should be most carefully evaluated before applying the diet in clinical settings.”1Erickson N, Boscheri A, Linke B, Huebner J. Systematic review: isocaloric ketogenic dietary regimes for cancer patients. Medical Oncology. 2017 May;34(5):72. Individualized close monitoring of the diet and ongoing education and support is recommended to improve safety and enhance completion of the KD.2Karen Collins, MS, RDN, CDN, FAND, Oncology Dietitian and Nutrition Advisor to the American Institute for Cancer Research. Presentation March 2017: “Culinary Translation in Breast Cancer Care and Survivorship” in Washington, DC; Erickson N, Boscheri A, Linke B, Huebner J. Systematic review: isocaloric ketogenic dietary regimes for cancer patients. Medical Oncology. 2017 May;34(5):72; Oliveira CL, Mattingly S, Schirrmacher R, Sawyer MB, Fine EJ, Prado CM. A nutritional perspective of ketogenic diet in cancer: a narrative review. Journal of the Academy of Nutrition and Dietetics. 2017 Mar 30. pii: S2212-2672(17)30115-6; Winters N, Kelley JH. The Metabolic Approach to Cancer: Integrating Deep Nutrition, the Ketogenic Diet, and Nontoxic Bio-Individualized Therapies. Vermont: Chelsea Green Publishing. 2017; Lise Alschuler, email communications, September 18, 2017 and October 24, 25, 26, 2017.

Also, because any anticancer effects of a ketogenic diet are due to metabolic changes, we highly recommend you be carefully assessed by a qualified physician or practitioner to determine the specific manipulation that might work best in relation to the metabolic characteristics of your cancer.

Preliminary evidence of low adherence and completion rates among people following a ketogenic diet; researchers interpret these as an indication that side effects or quality of life during KD are a barrier to participation or adherence

  • Low rate of acceptance of the KD dietary restrictions by people with cancer—only 37% of those on the KD were able to follow the diet for the duration of the study—in a review of clinical studies3Erickson N, Boscheri A, Linke B, Huebner J. Systematic review: isocaloric ketogenic dietary regimes for cancer patients. Medical Oncology. 2017 May;34(5):72. 
  • Quality of life was a factor in decisions to decline participation in a trial which also had poor retention—only 4 of 12 patients completed the 3-month diet—among people with glioblastoma in a small RCT4Martin-McGill KJ, Marson AG et al. Ketogenic diets as an adjuvant therapy for glioblastoma (KEATING): a randomized, mixed methods, feasibility study. Journal of Neuro-oncology. 2020 Mar;147(1):213-227.

Side effects and adverse events

Short-term effects in early implementation of this diet, usually transient and easily managed:5Branco AF, Ferreira A et al. Ketogenic diets: from cancer to mitochondrial diseases and beyond. European Journal of Clinical Investigation. 2016 Mar;46(3):285-98; Schmidt M, Pfetzer N, Schwab M, Strauss I, Kammerer U. Effects of a ketogenic diet on the quality of life in 16 patients with advanced cancer: a pilot trial. Nutrition & Metabolism. 2011 July 27;8(1):54.

  • Nausea and vomiting (most common)
  • Constipation
  • Gastroesophageal reflux (heartburn)
  • Acidosis (a condition resulting from blood being too acidic, especially due to dehydration)
  • Dehydration
  • Lethargy
  • Low blood sugar (hypoglycemia)
  • Weight loss

People with advanced metastatic tumors following a ketogenic diet had stable diarrhea but worse nausea and vomiting over time6Schmidt M, Pfetzer N, Schwab M, Strauss I, Kammerer U. Effects of a ketogenic diet on the quality of life in 16 patients with advanced cancer: a pilot trial. Nutrition & Metabolism. 2011 July 27;8(1):54.

“As cancer patients are particularly susceptible to clinically significant malnutrition in the form of weight loss from both fat and muscle mass, this side effect should be most carefully evaluated before applying the diet in clinical settings.”7Erickson N, Boscheri A, Linke B, Huebner J. Systematic review: isocaloric ketogenic dietary regimes for cancer patients. Medical Oncology. 2017 May;34(5):72.

Other short-term effects observed in clinical studies:8Erickson N, Boscheri A, Linke B, Huebner J. Systematic review: isocaloric ketogenic dietary regimes for cancer patients. Medical Oncology. 2017 May;34(5):72.

  • Anemia
  • Bad breath (halitosis)
  • Decreased amino acid levels
  • Eye nerve damage (optic neuropathy)
  • Flu-like symptoms or fatigue
  • Functional changes in basal ganglia, granulocytes (neutrophils) and thrombocytes (platelets)
  • High uric acid levels in blood (hyperuricemia)
  • Inflammation of the pancreas (pancreatitis)
  • Itching (pruritus)
  • Low blood calcium levels (hypocalcemia)
  • Low blood magnesium levels (hypomagnesemia)
  • Low or high blood potassium levels (hypo- or hyperkalemia)
  • Swelling of feet

Common long-term effects:9Branco AF, Ferreira A et al. Ketogenic diets: from cancer to mitochondrial diseases and beyond. European Journal of Clinical Investigation. 2016 Mar;46(3):285-98; Sharman MJ, Kraemer WJ et al. A ketogenic diet favorably affects serum biomarkers for cardiovascular disease in normal-weight men. Journal of Nutrition. 2002 Jul;132(7):1879-85.

  • High blood lipids (hyperlipidemia): most common, although with conflicting reports of improvement in lipid profile
  • Heart muscle disease (cardiomyopathy)
  • High cholesterol (hypercholesterolemia), although with conflicting reports of improvement in cholesterol
  • Kidney stones (nephrolithiasis)

Other long-term side effects observed in clinical studies:10Erickson N, Boscheri A, Linke B, Huebner J. Systematic review: isocaloric ketogenic dietary regimes for cancer patients. Medical Oncology. 2017 May;34(5):72.

  • Thickening and hardening of the walls of the arteries (arteriosclerosis)
  • Carnitine deficiency, a metabolic state in which carnitine concentrations in plasma and tissues are less than the levels required for normal function 
  • Decreased growth in children and adolescents
  • Deficiencies of vitamins, minerals and enzymes 
  • Irregular menstrual periods
  • Loss of bone density (osteopenia or osteoporosis) or bone fractures

Keep reading about ketogenic diet

Author

Laura Pole, RN, MSN, OCNS

Senior Clinical Consultant
View profile

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

Nancy Hepp, MS

Lead Researcher and Program Manager
View profile

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

Reviewers

Lise Alschuler, ND, FABNO

Naturopathis oncologist and CancerChoices advisor
View profile

Dr. Alschuler, ND, FABNO, is a professor of Clinical Medicine at the University of Arizona where she is the associate director of the Fellowship in Integrative Medicine at the Andrew Weil Center for Integrative Medicine. She received her undergraduate degree from Brown University and completed her naturopathic medical training at Bastyr University where she also completed her residency in general naturopathic medicine. She is board certified in naturopathic oncology and maintains a clinical practice out of Naturopathic Specialists, LLC. Dr. Alschuler co-hosts a podcast, Five To Thrive Live!. She is co-author of Definitive Guide to Cancer, now in its 3rd edition, and Definitive Guide to Thriving After Cancer.

Lise Alschuler, ND, FABNO Naturopathis oncologist and CancerChoices advisor

Last update: June 9, 2022

CancerChoices provides information about integrative in 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 psychosocial therapy, and acupuncture therapies and self-care lifestyle 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.

References[+]