3. Milk
Milk is not a problem for most people but those with a lactose intolerance should certainly stay away from it. That’s because lactose intolerance is caused by an inability to produce lactase, which in turn prevents you from being able to break down and digest lactose. This causes lactose to build up inside the intestines where it can give off gas, leading to stomach upsets, wind and yes – constipation.
This is actually very common, with anything from 70-90% of the population of Earth suffering from the condition (depending on which reports you believe). But what is important to recognize is that the majority of these people are based outside of the US.
There is actually a big racial difference here, with those with African American and Asian descent being far more likely to experience the intolerance.