Too Much Of Something
Too much of one thing can be hard on the body. Eating too much candy can of course end up being too much sugar for the body to handle. Eating too much meat can cause gout in some people. Most people know that they need some sort of balanced plan to how they eat. They need to eat plenty of fruits and veggies and so on.
There are some groups out there for example that eat 80% or more fruit. Even though fruit can be really good for you, it does usually contain lots of natural occurring sugars. So maybe for some people, eating a meal plan like this can do more bad than good. So be careful to not over do too much of any one food.