Fasting and Fasting-Mimicking Diets

About this approach

Fasting approaches range from limiting eating to certain hours to periods of substantial food restriction. A fasting-mimicking diet uses a specified reduced-food plan rather than complete abstinence. These methods are being studied during cancer treatment, but they are not established ways to improve cancer outcomes for everyone. Someone losing weight, struggling to eat or taking glucose-lowering medicines may face particular risks.

Where it fits: Investigational nutrition strategy during cancer treatment

Where this treatment is used

Animal findings and early human studies have prompted research into whether fasting changes treatment tolerance or response. In the randomized DIRECT study, a fasting-mimicking diet was tested with preoperative chemotherapy in a selected breast-cancer population. Some response measures favored the diet, but overall treatment toxicity was not reduced, and adherence and different analyses complicate interpretation. Studies also differ in the eating pattern, timing and accompanying medicines. A registered study with nutrition monitoring offers a clearer framework for testing these questions than a universal fasting prescription.

Procedure and practical considerations

Reduced intake can cause dehydration, weakness, dizziness and inadequate nutrition. Losing muscle or weight unintentionally is especially concerning during cancer therapy. Fasting may also disrupt medicines that must be taken with food and can create blood-sugar problems in people using diabetes treatments. Symptoms and nutritional decline need prompt reassessment; hunger or metabolic measurements are not reliable indicators of anticancer benefit.

Clinics reporting this approach

These clinic profiles mention this approach in their published materials. Open a profile to compare locations, services, practical details, and ways to get started.