Lactose intolerance refers to a condition where the body lacks lactase enzyme, leading to symptoms such as abdominal pain, diarrhea, and bloating after consuming dairy products.

It does not have a direct correlation with the ability to gain weight, because aside from dairy products, there are many other foods that a person can eat. If someone is lactose intolerant and cannot consume dairy, they can still eat many other things, which can also contribute to weight gain. Therefore, individuals with lactose intolerance can still gain weight, as there is no direct relationship between lactose intolerance and obesity.