Biological age and the number on your birth certificate are not the same thing. Your chronological age only moves one way. Your biological age can run ahead of it or behind it. Here's what biological age is, what's known to influence it, and what clinical research on the Prolon 5-Day Fasting Mimicking Diet (FMD) showed.
What is biological age, and how is it different from your actual age?
What is biological age?
Biological age is an estimate calculated from biomarkers associated with aging and health risk. It is sometimes called bio-age, and unlike your birth date, it can run higher or lower than your chronological age. A biological age below your chronological age is generally associated with lower health risk.
Chronological age is fixed. Biological age isn't, which is why it's become a focus of longevity research: if it can be measured, it may also be something you can influence.
What influences biological age
The biomarkers used to estimate biological age are shaped by ordinary habits: how you eat, how much you move, how well you sleep, and how you manage stress. Regular physical activity is one of the most consistently studied habits connected to healthy aging, and so is consistent sleep.
Diet has been tested directly. CALERIE, a randomized controlled trial of 220 healthy, non-obese adults over two years, found that being assigned to cut calorie intake by 25 percent slowed the pace of biological aging on one measure (DunedinPACE), by a small amount, but didn't produce a significant change on other biological-age measures in the same study (Waziry et al., Nature Aging, 2023). Two of this study's authors are listed inventors of DunedinPACE, a measure used in the study, which Duke University and the University of Otago licensed to a commercial entity. Research like CALERIE is the kind of evidence base the Prolon 5-Day FMD's own clinical research sits inside, not apart from.
Can diet lower your biological age?
Three consecutive monthly cycles of the Prolon 5-Day FMD were associated with a median reduction of approximately 2.5 years in biological age.
What the Fasting Mimicking Diet data showed
What did the Fasting Mimicking Diet study find?
That result comes from a peer-reviewed study published in Nature Communications in 2024 (Brandhorst et al., PMID 38378685). The diet used in this study was provided by L-Nutra, the company behind Prolon. The University of Southern California has licensed intellectual property under study in this research to L-Nutra and may receive royalty payments from it. Two authors who hold equity in L-Nutra did not take part in collecting or analyzing the data. Biological age was calculated from blood-based clinical markers; liver fat was a separate measure. The study measured liver fat by MRI, as its own outcome.
Is biological age reduction permanent?
The study reported biological age after three consecutive monthly cycles. It doesn't describe a permanent change, and the data doesn't show whether, or for how long, a reduction holds once the cycles stop.
What a 5-Day FMD cycle involves
What is the recommended protocol?
The recommended protocol is three consecutive monthly cycles to start, fifteen days total spread over three months, followed by three to four cycles a year for maintenance.
A cycle itself is five days, built around precisely formulated, plant-based meals designed to keep your body in a fasting state while you still eat. It has a defined start and end, repeated on a schedule, not a single event or an open-ended change to how you eat day to day.
The Prolon 5-Day FMD provides every meal for all five days, and our ingredients and supplement facts page covers exactly what's in each day's meals.
Prolon's approach is built on more than 25 years of research and over 40 clinical trials, backed by more than 200 issued or pending patents globally, and developed in collaboration with research partners including the USC Longevity Institute, Mayo Clinic, and Stanford.
If you want to see what three consecutive monthly cycles look like, the Prolon 5-Day FMD is where to start.
