A small study has found that people whose biological age is younger than their chronological age lost more weight during a medically supervised fast.
Researchers led by Steve Horvath at the University of California, Los Angeles, recruited 32 volunteers aged 25 to 72 with no known health conditions. The participants consumed 200 to 250 calories daily for 12 days through fruit juice, vegetable broths and honey in three windows each day.
The team tracked biological age using 12 epigenetic clocks. Those participants judged to have a younger biological age at the start of the study lost more weight than those who were biologically older.
Horvath said the mechanism is unknown but may involve better metabolic adaptability in younger individuals. The study was published on the bioRxiv preprint server and the authors stressed it was not suitable to attempt without medical supervision.
Horvath called for further research into whether the pattern holds under less extreme diets. A healthy lifestyle including exercise and not smoking can help lower biological age, he added.