Effects of Intermittent Fasting on Health, Aging, and Disease
Rafael de Cabo, Ph.D., & Mark P. Mattson, Ph.D.
N Engl J Med, Dec 26, 2019 • DOI: 10.1056/NEJMra1905136
Key Insights
- Metabolic Switching: Fasting shifts the body from glucose to ketones as fuel. This boosts efficiency, reduces inflammation, and supports brain health.
- Cellular Stress Resistance: Fasting activates repair pathways (autophagy, DNA repair, antioxidant defenses) and suppresses inflammation.
- Health Benefits: Evidence shows improvements in insulin sensitivity, blood pressure, heart health, and resistance to chronic diseases.
- Beyond Weight Loss: Many benefits occur even without major weight loss — including better glucose control, endurance, and cognition.
Evidence from Studies
- Animals: Intermittent fasting extends lifespan, reduces obesity, protects against diabetes, heart disease, cancer, and neurodegeneration.
- Humans: Clinical studies show fasting improves insulin levels, waist circumference, heart-rate variability, memory, and cognitive performance.
- Neuroprotection: IF enhances learning, memory, and may delay neurodegenerative processes like Alzheimer’s and Parkinson’s.
Popular Regimens
- Time-Restricted Feeding: Eating within 6–8 hours daily (e.g., 16:8).
- 5:2 Fasting: Eating normally 5 days per week, fasting (500–700 kcal) on 2 days.
- Alternate-Day Fasting: Fasting every other day or large calorie reductions.
Practical Considerations
- Initial side effects include hunger, irritability, and low concentration — often improving after ~1 month.
- Gradual adaptation (reducing eating window step by step) helps long-term success.
- Medical guidance and proper nutrition are essential, especially for those with health conditions.
Conclusion: Intermittent fasting offers broad-spectrum benefits for metabolism, aging, and disease prevention. While long-term human trials are ongoing, current evidence suggests fasting is a powerful tool for improving health span and possibly lifespan.
📖 Source: Rafael de Cabo & Mark P. Mattson.
Effects of Intermittent Fasting on Health, Aging, and Disease.
New England Journal of Medicine, 2019; 381:2541–2551.
https://doi.org/10.1056/NEJMra1905136