Fasting Mimicking Diet (FMD) — Diets

Periodic 5-day low-calorie plant-based protocol designed to mimic fasting physiology while allowing food intake.

Overview

The Fasting Mimicking Diet (FMD), developed by Valter Longo at USC, is a 5-day low-calorie, low-protein, high-fat plant-based protocol providing ~1,100 kcal on day 1 and ~800 kcal on days 2-5. It is designed to trigger fasting-like metabolic changes (reduced IGF-1, elevated ketones, autophagy) while allowing food consumption. Multiple clinical trials (including the landmark 2017 Science Translational Medicine study) demonstrate benefits for body composition, blood pressure, CRP, IGF-1, fasting glucose, and biological age markers. Monthly cycles (5 days per month for 3 consecutive months) are the standard protocol.

Indications

  • Biological age reduction
  • Cardiometabolic risk factor improvement
  • IGF-1 and growth factor reduction
  • Stem cell-based regeneration
  • Body composition improvement

Mechanism of Action

Low protein and calorie intake reduces circulating IGF-1 and insulin, mimicking the hormonal milieu of water fasting

Dosing

CompoundDoseFrequencyNotes
Fasting Mimicking Diet~1,100 kcal day 1; ~800 kcal days 2-55 consecutive days per month for 3 monthsHigh fat, low protein, plant-based; ProLon is the commercial kit

Evidence Grade

GRADE C

Safety & Contraindications

  • Fatigue, headaches, and weakness are common during the 5-day cycle
  • Not recommended for individuals with BMI < 18.5 or eating disorders
  • Diabetic patients require medical supervision and medication adjustment
  • Gradual return to normal diet after each cycle to avoid GI distress
  • Consult physician if on blood pressure or diabetes medications