Intermittent Fasting: Is the Wait Worth the Weight?
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Purpose of Review
We review the underlying mechanisms and potential benefits of intermittent fasting (IF) from animal models and recent clinical trials.
Numerous variations of IF exist, and study protocols vary greatly in their interpretations of this weight loss trend. Most human IF studies result in minimal weight loss and marginal improvements in metabolic biomarkers, though outcomes vary. Some animal models have found that IF reduces oxidative stress, improves cognition, and delays aging. Additionally, IF has anti-inflammatory effects, promotes autophagy, and benefits the gut microbiome. The benefit-to-harm ratio varies by model, IF protocol, age at initiation, and duration.
We provide an integrated perspective on potential benefits of IF as well as key areas for future investigation. In clinical trials, caloric restriction and IF result in similar degrees of weight loss and improvement in insulin sensitivity. Although these data suggest that IF may be a promising weight loss method, IF trials have been of moderate sample size and limited duration. More rigorous research is needed.
KeywordsIntermittent fasting Fasting Obesity Calorie restriction Metabolism Insulin resistance Weight loss
Intermittent calorie restriction
Alternate-day energy restriction
Continuous energy restriction
Randomized controlled trial
Glucose infusion rate
Reactive oxygen species
- ad lib
This work was supported in part by the National Institutes of Health [UL1TR001430, P30DK046200, T32DK007201].
Compliance with Ethical Standards
Conflict of Interest
Mary-Catherine Stockman declares that she has no conflict of interest.
Dylan Thomas declares that he has no conflict of interest.
Jacquelyn Burke declares that she has no conflict of interest.
Caroline M. Apovian has received research funding through grants from Sanofi-Aventis, Orexigen, Aspire Bariatrics, GI Dynamics, MYOS, Takeda, Gelesis, Vela Foundation, Dr. Robert C. and Veronica Atkins Foundation, Coherence Lab, Energesis, Patient-Centered Outcomes Research Institute (PCORI), the National Institutes of Health (NIH), Eli Lilly, and MetaPrteomics LLC; has received compensation from Nutrisystem, Zafgen, Sanofi-Aventis, Orexigen, Novo Nordisk, GI Dynamics, Takeda, Scientific Intake, Gelesis, Merck, Johnson & Johnson, Amylin, EnteroMedics, Arena Pharmaceuticals, Rhythm Pharmaceuticals, and Xeno Biosciences for service on advisory boards; and owns stock in Science-Smart LLC.
Human and Animal Rights and Informed Consent
This article does not contain any studies with human or animal subjects performed by any of the authors.
Papers of particular interest, published recently, have been highlighted as: • Of importance •• Of major importance
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