Lactose Intolerance
Lactose Intolerance is when your body cannot break down the sugar found in milk.
Think of it this way
A jar of sugar cubes sits on a cutting board next to small scissors. The scissors cut each cube into bits that fit through a fine mesh strainer. Without the scissors, whole cubes get stuck in the strainer. In lactose intolerance, the body has no scissors, so the sugar piles up and cannot move on.
Explaining lactose intolerance by grade level
Milk has a type of sugar in it. Your belly needs a helper to break that sugar apart. Some people do not make enough of that helper. Their stomachs may hurt when they drink milk.