Could Intermittent Energy Restriction and Intermittent Fasting Reduce Rates of Cancer in Obese, Overweight, and Normal-Weight Subjects? A Summary of Evidence.
Level 5 - mechanism / opinion, no new human data
Narrative review synthesizing animal models and short-term human biomarker studies without systematic review methodology
PubMed 27422504 · doi:10.3945/an.115.011767
What was done
The authors summarized animal studies evaluating tumor incidence during intermittent energy restriction (IER) or intermittent fasting (IF) compared with continuous energy restriction (CER) or ad libitum feeding. They also reviewed available human studies (≤6 months) comparing IER or IF with CER on cancer-related biomarkers in overweight, obese, and normal-weight individuals.
What was found
No quantitative numerical values were reported in the abstract. In spontaneous mouse tumor models, IER alternating with ad libitum feeding for 1, 2, or 3 weeks was reported to be superior to CER in reducing tumor rates. In short-term human studies (≤6 months) in overweight and obese subjects, IER led to greater improvements in insulin sensitivity (homeostasis model assessment) than CER, with comparable reductions in adipokines and inflammatory markers, and minor changes in the insulin-like growth factor axis. No human data were available comparing IER or IF with CER in normal-weight individuals.
Why it matters
This review highlights that while intermittent fasting shows preclinical antitumor promise and metabolic biomarker improvements, current evidence is insufficient to recommend IER over continuous caloric restriction for cancer prevention in humans.
Limits
Direct clinical cancer endpoints in humans were not evaluated, relying instead on animal tumor models and short-term surrogate biomarkers (≤6 months). No sample sizes or numerical effect estimates were provided in the abstract. Data for normal-weight human populations are completely lacking, and long-term adherence, safety, and efficacy remain untested.
Cited by
- supports In animal models, intermittent fasting suppresses spontaneous tumor formation, inhibits growth of implanted cancer cells, and enhances cancer cell killing by chemotherapy and radiation.