一项发表在《科学》杂志上的研究表明，碳水化合物在人类四百万年的进化过程中提供了超过一半的总能量需求，其主要来源为果实和蜂蜜[1]。这项由David Raubenheimer、Jennie Brand-Miller和Les Copeland等研究者进行的研究通过对不同时期人族饮食的建模发现，大脑发育所需的葡萄糖不能仅从肉类获得，而必须依赖植物中的天然糖分[1]。人脑在静息状态下消耗身体总能量的五分之一，远高于非人灵长类动物的不到一半，五岁儿童更是将其维持生命所需能量的66%用于大脑[1]。
研究指出，早期人族祖先露西（南方古猿）超过三分之二的能量来自天然糖分[1]。大约一百万年前，火的掌握使得熟淀粉能够取代部分天然糖分[1]。大约十万年前，磨石和炉灶的出现表明谷物中的淀粉变得更易获取[1]。研究还揭示，女性在哺乳期每天使用约80克葡萄糖来生产人乳中的糖分，而现代人类需要约一半的能量来自碳水化合物[1]。这一发现解释了现代人类对甜食的渴望，以及低碳水化合物饮食的健康意义[1]。
A study published in Science reveals that carbohydrates supplied more than half of the total energy requirements throughout four million years of human evolution, with fruits and honey serving as the primary sources [1]. Researchers modeled the diets of different hominin species across evolutionary periods to demonstrate that the glucose needed for brain development could not be obtained from meat alone, but rather depended on natural sugars from plants [1].
The human brain consumes one-fifth of the body's total energy at rest, significantly more than in non-human primates, which use less than half [1]. This demand is particularly acute in early childhood—five-year-old children allocate 66 percent of their energy expenditure to their brains [1]. Early hominin ancestors such as Lucy (Australopithecus) derived more than two-thirds of their energy from natural sugars [1]. The discovery explains modern humans' attraction to sweet foods and provides insight into the health implications of low-carbohydrate diets, as carbohydrates remain essential, with contemporary humans requiring roughly half their energy intake from this macronutrient [1].
Over time, technological advances gradually shifted the source of carbohydrate intake. Around one million years ago, the mastery of fire enabled cooked starches to replace some of the natural sugars in the diet [1]. Approximately 100,000 years ago, the emergence of grinding stones and hearths indicated that starch from grains became more accessible [1]. Additionally, lactating women expend roughly 80 grams of glucose daily to produce the sugars present in human milk, underscoring carbohydrates' critical role in human reproduction and development [1].
