Brett Arends's ROI: Want to slow the aging process? It may be as simple as eating less.

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Could going on a diet slow down the process of aging?

Quite possibly, according to new research.

A two-year study of 128 middle-aged people who cut back on calories by 25% found that their bodies aged more slowly as a result.

“The intervention effect…represented a roughly 2-3% slowing in the pace of aging,” reported the team of researchers at Columbia University’s Mailman School of Public Health. That may not sound like much, but it’s enough to lower mortality risk by 10-15%. The effects, they report, were “similar to the effect of a smoking cessation intervention.”

Given that quitting smoking is about the best thing you can do for your health—if you are a smoker—that is high praise.

The study, run by the U.S. National Institute of Aging, tracked how quickly the subjects’ bodies were aging by studying changes in the DNA of the participants, and especially chemical tags called methylation marks, extracted from white blood cells. DNA methylation marks “regulate the expression of genes and are known to change with aging,” the study reports.

The participants had an average age of 38. Some 70% were women, and 77% were ethnically Caucasian. The effects of calorie restriction on 128 subjects was compared to a control group of 69. The participants still ate healthy diets with all the important vitamins and nutrients—just in smaller amounts.

One of the problems with studies like these is that you can’t just lock people up in a lab for two years and control what they eat. For the research project, those undertaking calorie restriction were given a month’s worth of daily meals and meal plans to start them off, and 24 weeks of group and individual counseling. They were also monitored along the way for things like weight loss and body fat percentage.

The researchers acknowledge the limitations. However, their analysis suggested that participants who stuck to the diet best and who cut the most calories, saw the aging slow the most. They suspect their findings represent “the lower bound” of the benefits of dieting: In other words: if anything, the real world results might be even better.

Two years is just a starter. “Decades of follow-up will be required to determine if the…intervention affected disease onset or lifespan,” the researchers wrote.

But the latest study adds to the research suggesting a link between cutting back on calories and living longer—a link that has already been found to exist in multiple other species.

Meanwhile in the U.S., and in much of the developed world, we are heading in the opposite direction. It is now six years since the Cleveland Clinic reported that obesity was costing Americans more lost life years than smoking.