IGF-1 and fasting

Definition

IGF-1 (Insulin-like Growth Factor 1) is a growth hormone that significantly decreases during prolonged fasting, favoring autophagy and potentially increasing longevity.

How it works

IGF-1 is an anabolic hormone produced primarily by the liver in response to growth hormone, mediated by a protein- and calorie-rich diet. During a high-calorie diet, elevated IGF-1 signals the body of sufficient resource availability, promoting growth, reproduction, and anabolic cellular processes. However, chronic overactivation of IGF-1 has been linked to accelerated aging, increased cancer risk, and reduced lifespan. During fasting, IGF-1 levels drop 20-40%, deactivated growth pathways, and activated cellular maintenance mechanisms such as autophagy.

Role

Regulatory hormone of cellular growth whose reduction by fasting activates health and longevity mechanisms.

Examples

• Elevated IGF-1 after a protein-rich animal meal
• 30% decrease in IGF-1 after 48 hours of fasting
• Correlation between chronically elevated IGF-1 and breast cancer risk
• Protein-poor diets reducing IGF-1 and increasing lifespan in animals

Recommendations

Alternate between periods of normal protein consumption and fasting to optimize IGF-1 levels · Avoid chronic overconsumption of animal proteins that maintains elevated IGF-1 · Practice regular intermittent fasting to benefit from IGF-1 reduction and its protective effects.

Key takeaway

Fasting reduces IGF-1, activating cellular renewal and potentially increasing longevity and protection against chronic diseases.

Related terms