Many nutrition experts say that breakfast gives the body energy after a long night without food. Children who eat breakfast often concentrate better at school. A healthy breakfast might include whole-grain bread, eggs, fruit or yogurt. These foods give lasting energy because the body digests them slowly. Sugary cereals and sweet pastries, by contrast, give a quick burst of energy and then leave a person hungry again. Some adults skip breakfast because they are in a hurry or are trying to lose weight, but this does not always help; people who skip meals may eat more later in the day. Of course, the best breakfast differs from person to person, and anyone with a health problem should ask a doctor. Still, a simple meal in the morning is a good habit for most people.

Question: Why does the writer say that anyone with a health problem should ask a doctor?