The word "diet" probably brings to mind meals of lettuce and cottage cheese. By definition, "diet" refers to what a person eats or drinks during the course of a day.

A diet that limits portions to a very small size or that excludes certain foods entirely to promote weight loss may not be effective over the long term. Rather, you are likely to miss certain foods and find it difficult to follow this type of diet for a long time.

A healthy diet is one that is arrived at with the intent of improving or maintaining optimal health. This usually involves consuming nutrients by eating the appropriate amounts from all of the food groups, including an adequate amount of water.