Some Body Help Me

Does diet relate to food? If you do not eat food, do you have a healthy diet? Maybe these questions seem stupid but I am really confused and need some help. I just finish eating at the "Food Plantation". It has good food and when you feel like pigging out it is a good place to go. Well my question came up while I was eating. I was all alone on this occasion. Eating alone can be boring and I forgot to bring a book. So, as I am eating I look at the wall for pictures or just generally try to entertain myself. I really cannot stare at the other people because it makes them uncomfortable and I really do not like black eyes or bitchy old ladies chewing me out. I read a saying printed on the wall. It said, "Food is a part of a good diet". OK, I am thinking. But what kind of food? It does not make any judgments. It only says food. Well, not being a dietitian, I am not sure if this is a correct statement. I am confused, so I am asking if anyone out there can help me out on this issue. Is there some other kind of diet?