I would say True because fad diets usually have you stay away from certain food groups and that makes your eating habits unhealthy. Certain fad diets can cause lack of very important nutrients that the body needs which isn't good. Lack of nutrients can cause diseases (that can cause death) and deficiencies. Even though they offer quick weight loss doesn't mean its good for your body and well being. You should ask a doctor before doing any drastic diet changes. This is just my answer and opinion. I don't know very much hope this was some what helpful.