How does the concept of metabolic acidity (acid-ash) fundamentally differ from the immediate chemical acidity caused by carbonic acid in beverages?
Metabolic impact is slow and chronic, judged by mineral residue after digestion, unlike carbonic acid's immediate, transient chemical effect.
Dietary acidity is assessed through two very different lenses. The acidity from carbonic acid is an immediate chemical property of the beverage before ingestion, resulting from a gas-water equilibrium, and its effect is transient, dissipating as the gas leaves the liquid. Metabolic acidity, often discussed in terms of acid-ash or alkaline-ash diets, relates to how the minerals remaining after the food is digested affect the body's long-term $ ext{pH}$ balance. Foods like meat and eggs, high in sulfur-containing amino acids, produce an acidic residue slowly over time, representing a chronic metabolic load, which is wholly separate from the initial chemical tartness provided by dissolved $ ext{CO}_2$ in a drink.
