在《源头节食》一书中,营养学家Elizabeth Somer断言:某些吃的渴望在人类生存和进化中曾经起到了重要作用。“几十万年以前,脂肪和糖是很缺乏的,”她这样写道。“而脂肪是热量重要来源(每克脂肪提供的卡路里是蛋白质或淀粉的两倍多),因此我们的祖先在当时并不需要控制脂肪的摄入量。相反,当他们发现富含脂肪的食物时,他们有多少吃多少,并练就了一种无限储存过多热量的能力。 In Sour Diets, nutritionist Elizabeth Somer asserted that certain eating cravings played an important role in human survival and evolution. ”Hundreds of thousands of years ago, fat and sugar were scarce,“ she wrote. ”And while fat is an important source of calories (more than twice as much calories per gram of fat as protein or starch), our ancestors did not need to control their fat intake at the time. Instead, when they found fat-rich How much they eat, how much they eat, and practicing an unlimited capacity to store excess calories.