A bunch of recent studies have shown that limiting daily calories can result in longer life in worms, flies, mice, and monkeys. The research has shown that eating less food, but not to the point of being malnourished, brings on metabolic, hormonal, and other little-understood changes that all work together to lengthen lifespan.

A recent study on humans published in the Journals of Gerontology, Series A: Biological and Medical Sciences has shown that cutting back on calories can also drop biological age. Researchers from the Duke University School of Medicine took 220 people and gave a random sampling of them a diet where calories were restricted by 25% of the current diet, or told to maintain their normal intake for two years. They found that the 145 people selected to restrict their diet had an average 12% reduction in intake over the study length.

To calculate biological age, the scientists checked a bunch of biomarkers like cholesterol, blood pressure, and various blood tests before the study to show that everyone had a similar biological age based on their chronological age. When they checked on the participants at 12-month intervals, however, they found that the calorie-restricted group had an average drop in biological age of 0.11 years, while the regular group’s age rose by 0.71 years.

"Ours is the first study to test if caloric restriction can slow measured biological aging in humans in a randomized setting," said study lead author Daniel Belsky, Ph.D., an assistant professor at Duke. "Our findings suggest a template for developing and evaluating therapies designed to mimic the effects of caloric restriction to ultimately prevent chronic diseases."