Research

Energy balance

The age-related decline in resting metabolic rate (REE) is driven by the loss of body cell mass (BCM) rather than an intrinsic slowing of cellular metabolism, and this loss is only accurately captured by Total Body Potassium (TBK) measurement.

Your metabolism doesn't inherently slow down as you age; rather, you lose the metabolically active tissue (muscle and cells) that drives it. To maintain your energy expenditure, you must prioritize preserving muscle mass through resistance training and adequate protein intake, rather than accepting metabolic decline as inevitable.

GoodRefutesHIGH confidence
It is the decline in cell mass with age, detectable by TBK but not by other methods, rather than any metabolic alteration, that explains the decline in FFM-adjusted REE with age.
Ronenn Roubenoff et al. · The Journals of Gerontology Series A · 2000

Why this rating

Large sample size (n=131), rigorous methodology comparing four distinct body composition methods, and consistent findings across sexes.

Source

The Effect of Gender and Body Composition Method on the Apparent Decline in Lean Mass-Adjusted Resting Metabolic Rate With Age

Ronenn Roubenoff et al. · The Journals of Gerontology Series A · 2000

DOI 10.1093/gerona/55.12.m757

cross_sectional · n=131Cited 57×
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DOI resolved against Crossref · corpus check 2026-06-10

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