Is a ketogenic diet effective as a treatment for cancer?

Ketogenic Diet is Not Recommended as a Cancer Treatment

The ketogenic diet is not recommended as a treatment for cancer due to lack of clinical evidence for efficacy and potential risks of malnutrition in cancer patients. 1

Evidence Against Ketogenic Diet for Cancer Treatment

Lack of Clinical Evidence

• No clinical trials have demonstrated a benefit of ketogenic diet in cancer patients 1
• A 2021 systematic review of 39 studies with 770 cancer patients found no conclusive evidence for anti-tumor effects or improved overall survival 2
• Clinical evidence for the effectiveness of ketogenic diets in cancer patients is still lacking due to heterogeneous results and methodological limitations 2

Potential Harms

• Ketogenic diets may lead to insufficient energy intake and weight loss due to their low palatability 1
• These diets increase the risk of:
  • Insufficient intake of energy, fat, and protein
  • Micronutrient deficiency
  • Exacerbation of malnutrition 1
• The majority of patients on ketogenic diets experience significant weight loss and mild to moderate side effects 2
• Patient adherence to ketogenic diets was rather low in most studies 2

Recommended Nutritional Approach for Cancer Patients

The European Society for Clinical Nutrition and Metabolism (ESPEN) provides clear guidelines:

1. Prioritize adequate nutrition: Cancer patients should receive nutritional intervention to increase oral intake if malnourished or at risk of malnutrition 1
2. Avoid restrictive diets: Dietary provisions that restrict energy intake are strongly discouraged in patients with or at risk of malnutrition 1
3. Preferred approach:
   • Nutrition counseling to manage symptoms
   • Encourage intake of protein- and energy-rich foods
   • Use oral nutritional supplements when enriched diet is insufficient 1
   • If oral intake remains inadequate, consider enteral nutrition, followed by parenteral nutrition if necessary 1

Common Pitfalls in Cancer Nutrition

• Many "anti-cancer diets" including ketogenic diets are based on anecdotal evidence rather than scientific reasoning or solid evidence 1
• Information about these diets often comes from unverifiable sources in popular literature and internet rather than peer-reviewed literature 1
• Cancer patients are often anxious to try dietary approaches perceived as "protective," which should be acknowledged but followed by unbiased counseling about nutrition's actual capabilities and limitations 1
• There are no diets known to reproducibly cure cancer or prevent cancer recurrence 1

Research Context

While some preclinical studies suggest potential mechanisms by which ketogenic diets might affect cancer metabolism 3, 4, 5, these theoretical benefits have not translated to clinical outcomes. The American Cancer Society notes that there is little or no evidence supporting the use of alternative dietary therapies among cancer survivors 1.

Current research suggests that ketogenic diets should not be regarded as an alternative to standard cancer treatment 1. A 2017 systematic review concluded that more robust and consistent clinical evidence is necessary before ketogenic diets can be recommended for any cancer diagnosis or as adjunct therapy 6.