Why did 40% of the human population evolve to tolerate lactose? Lactose tolerance allows people to enjoy a wide variety of food, including milk, butter, ice cream, and cheese. People who have an...

Why did 40% of the human population evolve to tolerate lactose? Lactose tolerance allows people to enjoy a wide variety of food, including milk, butter, ice cream, and cheese. People who have an intolerance experience physical pain, so a tolerance evolved to avoid that. Babies rely on milk to survive, so they need to be able to tolerate lactose. Within cultures that rely on milk-producing animals, individuals who tolerated lactose had a survival advantage.