Best worst choice: aggravating a dairy intolerance

Expert insight:

People with dairy intolerances have difficulty producing lactase, the enzyme that breaks down lactose, explains Dominic Matteo, a level 2 masterclass instructor at Precision Nutrition in Cleveland. As a result, the sugars can't be absorbed by the colon and are instead fermented by bacteria, which causes a buildup of gas and water. That accumulation leads to the side effects listed above.

If you want to enjoy a slice of pizza or a scoop of ice cream, take a lactase-containing digestive supplement before or during your meal, Matteo says. 

Always choose fermented dairy products over non-fermented types, he adds. The process gives the bacteria time to break down lactose, making the foods easier to digest. Smart picks include Greek yogurt, kefir, and hard cheeses like Parmesan and Manchego—not milk, butter, and soft cheeses like mozzarella or Havarti.

Post-meal, fast for as long as it takes for your symptoms to subside. This gives your body time to digest the dairy without distraction. In turn, the food will leave your system more quickly. 

The bottom line:

There's rarely long-term damage from eating dairy if you have an intolerance, Matteo says, but frequent discomfort can have a negative effect on your overall well-being.