The Fasting-Mimicking Diet: 5 Days a Month
Valter Longo, PhD, Director of the USC Longevity Institute, developed and clinically trialed the fasting-mimicking diet (FMD): a low-calorie, low-protein, plant-based diet (roughly 800-1100kcal on day 1, tapering to roughly 500kcal on days 2-5) followed once a month. Disclosed commercial interest: Longo founded and holds an ownership stake in L-Nutra, maker of the commercial FMD kit ProLon; a DIY version following the same macronutrient targets (vegetable broths, nuts, olives) follows the same published methodology at lower cost. Hard longevity or mortality endpoints in humans are not yet established; do not oversell this beyond the published surrogate-marker outcomes.
Eat a low-calorie, plant-based day, roughly 800-1100 kcal, high in unsaturated fats and complex carbs, low in protein ~800-1100 kcal
Day 1 is designed to ease the body toward a fasting-like metabolic state without a sudden drop.
Eat a lower-calorie, plant-based diet, roughly 500 kcal, built around vegetable broths, nuts, and olives ~500 kcal/day
This is the core of the published protocol, designed to sustain the fasting-like metabolic state (reduced IGF-1, ketone production) for the remaining four days.
Follow the 5-day protocol once every month, returning to normal eating in between 5 days/month
The published research protocol uses monthly repetition, not a continuous or weekly pattern.
If skipping the commercial kit, match the same macronutrient targets yourself: vegetable broths, nuts, olives, complex carbs, staying within the calorie ranges above Matching the kcal targets above
The published methodology is the calorie and macronutrient pattern, not the specific commercial product; a DIY version following the same targets replicates the studied approach at lower cost.
The fasting-mimicking diet is designed to trigger some of the same metabolic shifts as water fasting (reduced IGF-1, ketone production, a switch toward fat metabolism) while still delivering enough nutrition to be followed periodically rather than requiring true fasting.
View sources
Valter Longo: Fasting-Mimicking Diet and Longevity
Valter Longo, Part 2
Valter Longo on the Fasting-Mimicking Diet
Fasting and fasting-mimicking diets for weight loss and prevention of metabolic disease
Not medical advice. This page is for education only and is not a substitute for professional medical care. Consult a qualified clinician before changing your health routine.
Independent curation. YourProtocol is an independent platform. This protocol is based on the publicly available work of Valter Longo, PhD and is not created, reviewed, endorsed by, or affiliated with Valter Longo, PhD or USC Longevity Institute.
Is this for you
- People interested in a structured, periodic approach to fasting-like eating rather than daily intermittent fasting
- Anyone who wants the DIY version of a commercial fasting kit they have seen advertised
Cautions
- Disclosed COI: Longo founded and holds an ownership stake in L-Nutra, maker of ProLon
- Hard longevity or mortality endpoints in humans are not yet established; surrogate metabolic markers are what the evidence actually supports
- Not appropriate during pregnancy, for anyone underweight, or without checking with a physician if you have a medical condition
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