Inspired by animal experiments showing that underfeeding enhances vitality and prolongs life by 30 percent or more, the US-based Calorie Restriction Society is slashing calorie intake in a bid to beat back the clock and halt the ageing process.
Society member Bob Cavanaugh said: "Some people are doing it strictly to enhance longevity," Cavanaugh said by phone from his home near Moorehead City in North Carolina.
"Others do it to avoid age-related disease, or because they already have diabetes, high cholesterol or clogged arteries and want to clean up their bodies by using diet."
A worldwide epidemic of obesity-related diseases has put a spotlight over the last decade on the link between food and health.
"In rich countries, 90 percent of the population probably eats, on average, about 50 percent too much," noted Christiaan Leeuwenburgh, head of the biology of aeging division at the University of Florida's College of Medicine.
"Even if they were to reduce their calorie intake by half, they would still only be at baseline," the optimal balance between energy input and output, he told AFP.
A wealth of scientific evidence has confirmed that maintaining that balance helps prevent type-2 diabetes, cardiovascular disease and cancer.
But experiments with both animals and humans have also shown that pushing one's calorie intake 10 to 20 percent below that baseline threshold, without lowering nutrients, may provide additional health advantages.
Luigi Fontana, a professor in the Division of Geriatrics and Nutritional Science of Washington University in St. Louis, Missouri, has led or co-authored more than a dozen studies on reduced calorie intake in humans.