Milk drunk ~ past the Milk DWI limit While in high school, I asked a black student there why he couldn’t drink milk and he called me racist. I just knew I could drink milk and everybody else I thought I knew could. That’s the 40% left. The reasons why Africa has stunted growth in brain development and in height; whereby, they cannot catch up. It’s not normal. Somewhat less than 40% of people in the world retain the ability to digest lactose after childhood. The numbers are often given as close to 0% of Native Americans, 5% of Asians, 25% of African and Caribbean peoples, 50% of Mediterranean peoples and 90% of northern Europeans. Sweden has one of the world’s highest percentages of lactase tolerant people.