Milk.

• Position: LIFE-CYCLE STUDIES

Overview

Milk has nourished young mammals for millions of years, but only humans skim, shake, "chocolify," and otherwise alter and commodity the milk of other species. Yet before cattle were domesticated some 9,000 years ago, milking a cow was an extreme sport and humane avoided or just Ignored their milk. And after weaning, they had no need for the enzymes that separate lactose sugars, so most older humans were lactose intolerant. But geneticists guess that 5,000-7,000 years ago in Europe a rare adventurous lactose-tolerant individual dared to drink the milk from his or her cattle. Those with similar genetic advantages eventually followed in a similar milky way.

Many of the cultures that first developed tastes for milk, such as the almost entirely lactose-tolerant Scandinavians, continue to drink it the most: The highest annual per-capita milk consumption worldwide is found in Finland (164...