Overview
What is it?
Intermittent fasting (IF) is an eating pattern that alternates between periods of fasting and normal eating. It includes methods like time-restricted eating (e.g., eating within an 8-hour window), alternate-day fasting, and fasting-mimicking diets. While not naturally occurring in humans, fasting has been practiced for centuries for religious, cultural, and health reasons .
How does it work?
Intermittent fasting works by triggering metabolic changes in the body. During fasting, the body shifts from using glucose as its primary energy source to burning fat, producing ketones. This process activates cellular repair mechanisms like autophagy (cleaning out damaged cells), reduces inflammation, and improves mitochondrial function. These changes enhance stress resistance, promote cellular health, and may slow aging .
What are the benefits?
Intermittent fasting has been shown to improve several health markers linked to longevity. Benefits include improved insulin sensitivity, reduced body fat, lower blood pressure, and enhanced heart rate variability. It also protects against age-related diseases such as diabetes, cardiovascular disease, and neurodegenerative disorders like Alzheimer’s and Parkinson’s. Animal studies suggest IF can extend lifespan by up to 80% in some species .
Effectiveness
What does the research say?
Research indicates that intermittent fasting can improve longevity by enhancing metabolic health and reducing the risk of age-related diseases. In animal studies, IF has been shown to extend lifespan by 11-80%, depending on the species and fasting regimen. Human studies suggest improvements in insulin sensitivity, reduced inflammation, and better cognitive function, which are associated with increased healthspan .
Side Effects
Mood changes
Short-term fasting can lead to mood swings, including increased feelings of depression, anxiety, and irritability, though some people report improved mood over time .
Fatigue and irritability
During fasting, some individuals may experience fatigue, irritability, and difficulty concentrating, especially in the initial stages of adapting to the fasting regimen .
Increased risk of hypoglycemia
Intermittent fasting can lower blood sugar levels, which may be risky for individuals with diabetes or those prone to hypoglycemia. Proper medical supervision is recommended .
Potential negative effects on reproductive health
In young animals, intermittent fasting has been linked to reduced reproductive function, though human studies are limited. More research is needed to understand its impact on human reproductive health .
Adverse effects in certain medical conditions
Prolonged fasting may worsen conditions like cancer or circulatory diseases and is not recommended for children, the elderly, or underweight individuals without medical supervision .
Evidence
Clinical Studies & Trials
[1] Impact of intermittent fasting on health and disease processes.
This review explores how intermittent fasting improves health by enhancing mitochondrial function, DNA repair, and autophagy. It also discusses its role in reducing age-related diseases and extending lifespan in animal models.
View study[2] The Effect of Fasting on Human Metabolism and Psychological Health.
This paper examines the metabolic and psychological effects of fasting, including its impact on mood, lipid metabolism, and glucose regulation. It highlights both the benefits and potential side effects of fasting.
View study[3] Fasting: From Physiology to Pathology.
This review discusses how intermittent fasting influences gut microbiome, metabolism, and aging. It highlights its role in extending lifespan and reducing age-related diseases in animal models.
View study[4] Fasting: molecular mechanisms and clinical applications.
This paper explores the molecular mechanisms of fasting, including its effects on ketogenesis, autophagy, and stress resistance. It also discusses its potential to extend lifespan and protect against diseases.
View study[5] The Health-Promoting Effects and the Mechanism of Intermittent Fasting.
This review highlights the health benefits of intermittent fasting, including its role in extending lifespan, improving cognitive function, and reducing oxidative stress. It also discusses potential side effects.
View study[6] Efficacy and Safety of Intermittent Fasting in People With Insulin-Treated Type 2 Diabetes (INTERFAST-2)-A Randomized Controlled Trial.
This clinical trial evaluates the safety and efficacy of intermittent fasting in individuals with type 2 diabetes. It focuses on hypoglycemia risk and insulin adjustments during fasting.
View study