After Geometry: Isolating the Residual Physiological Component of Metabolic Adaptation

Once the decelerating trajectory of human mass change is recognized as a geometric consequence of surface-area scaling, a substantial fraction of what has historically been labelled metabolic adaptation is removed from the explanatory burden of biology. What remains is a residual: any systematic deviation of observed mass or energy trajectories from the geometric baseline. This residual – not the raw deceleration – is the proper object of physiological investigation. The present paper outlines a framework for isolating and modelling it. Geometry supplies a baseline that is entailed by its premises and is direction-symmetric; biology is responsible only for what cannot be accounted for by that baseline. Distinguishing the two levels prevents the continued misattribution of geometric entailment to regulatory physiology and opens the way to more precise, less confounded models of true adaptive responses.