A 2025 study on more than 180 elite athletes found that the standard equations used to “predict” resting metabolic rate (RMR) are wildly unreliable—missing a large share of athletes who were actually experiencing metabolic suppression and low energy availability. In fact, depending on the equation used, the number of athletes flagged as having a low RMR ranged anywhere from 1% to 68%, despite nearly half being at real risk. The takeaway is simple: if you want to understand your true metabolic status, you can’t rely on generic formulas. Direct measurement through high-quality RMR testing is the only accurate way to assess how your body is functioning at rest.