Only a small percentage of the world's population is lactose intolerant.

The story behind the answer

False. Globally, lactose intolerance is common: about two-thirds of adults lose much of their ability to digest lactose (the sugar in milk) after childhood. Only a minority—those with “lactase persistence”—can routinely digest milk in adulthood.

Here’s why: Like most mammals, humans normally switch off the lactase enzyme after weaning. In some populations, genetic changes spread alongside dairy farming 5,000–10,000 years ago, keeping lactase active for life. Lactase persistence is frequent in Northern Europeans and some pastoralist groups in East Africa and the Middle East, but lactose intolerance is common in East Asian, Indigenous American, and many West African populations. Memory tip: Most mammals stop drinking milk after infancy—humans are mostly the same; long-term milk drinking is the exception, not the rule.