Evolutionary Medicine: New Avenues of Research on Sugar

Author(s): Riccardo Baschetti*


This article may open new avenues of research on sugar (sucrose), because it challenges experts in clinical nutrition by questioning two deep-rooted medical tenets that stigmatize sugar in the media. The first entrenched medical tenet claims that the metabolic effects of sugar depend on its ingested quantity, regardless of its form of ingestion, which accordingly is omitted in many experimental studies on sugar. In sharp contrast, evolutionary medicine stresses that concentrated sugar is harmful because it is nonexistent in nature, but diluted sugar is harmless because it is the most abundant carbohydrate of fresh fruit, which was the main food of our prehistoric ancestors for tens of millions of years. Consequently, fruit shaped genetically their metabolic physiology. Thanks to evolutionarily conserved physiological traits adapted to fresh fruit, our absorption of diluted sugar is harmlessly “linear?, i.e., slow and calorie-constant within the caloric range of fruit. Above this range, our absorption of concentrated sugar is harmfully “exponential?, i.e., precipitous. The second ingrained medical tenet claimsthat the quantity of sugar in sugar-sweetened beverages explains the reported association between their intake and some diseases. By contrast, evolutionary medicine emphasizes that this association reflects primarily the neglected metabolic effects of dietary salt, which was unknown for the 99.99% of our evolutionary existence. Salt unnaturally accelerates the absorption of sugar-sweetened beverages when they are ingested together with salt-containing foods, as generally occurs. By passing partly into those beverages, salt abnormally turns the linear harmless absorption of diluted sugar into a virtually exponential harmful absorption

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