Calories and the PACE Versus the Pace of Aging

“Calorie restriction slows pace of aging in healthy adults.” This headline for a press release from Columbia University sounds pretty impressive. Until you stop and read the paper – which comes to no such conclusion. It appears that the headline writers were referring not to the pace of aging, but to P.A.C.E. – the Pace of Aging Computed from the Epigenome. In their paper, the authors were specific in saying that this study is not conclusive about the effect restriction of calories has on aging:

“Ultimately, a conclusive test of the geroscience hypothesis will require trials with long-term follow-up to establish effects of intervention on primary healthy-aging endpoints, including incidence of chronic disease and mortality.”

Mixed Results in a Study of Epigenetic Markers

If you can get past the misleading PR spin, this is an interesting analysis. The data for it come from an RCT of 25 percent calorie restriction for two years, called the CALERIE study. Previously published in Lancet, the primary analysis showed that people had a tough time actually achieving a 25 percent calorie reduction for two years, despite intensive support. Their actual reduction in calories turned out to be 12 percent versus the control group. Even so, they did lose weight that was mostly fat mass and their cardiometabolic health improved.

What this study adds is a measurement of multiple surrogates for cellular aging derived from measures of epigenetic changes. One of those surrogates, the DunedinPACE DNAm algorithm, showed a significant improvement in the calorie restriction group. But other measures did not point to improvements in biological age.

A Tough Goal to Chase

People are keenly interested in slowing down the effect of aging, so earlier work showing that calorie restriction might have an effect on lifespan is tantalizing. It works great in mice. But it’s a tough goal to chase in humans because our baseline of lifespan is so much longer longer than mice. Plus, humans don’t live in a laboratory where you can take away a quarter of their food supply.

But the fascination with this proposition continues, even though real evidence that restricting calories will slow aging is absent and unlikely to appear for many years, if ever.

Click here for the study, here for the press release, and here for further perspective.

Aged Angel, painting by Odilon Redon / WikiArt

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February 11, 2023