We have been having a discussion about vocabulary around here lately and how words sometimes don't necessarily mean what you think they mean.
Case in point: Bear asked what the word "diet" meant. SugarPlum started to explain to him that a diet was where people eat less food so that they can lose weight and get skinny. I had to clarify that that wasn't exactly true, but that it was one example of a diet. A diet, basically, is what a person regulary eats, or what selection of foods he or she is consuming. This may or may not result in weight loss.
For instance, I am presently on the "Eat a Box of Girl Scout Cookies Each Night While You Sit on Your Ass and Play on the Computer" diet. And I haven't lost one single pound.