Why do you have a diet?

That depends on what type of diet you mean. There are many types of diet. Some diets treat a disease or condition. Other diets are for optimum health. Others diets are for weight loss or weight gain. For example, there is a diabetic diet, diverticulitis diet, irritable bowel diet, Crohn's disease diet, acne diet, autistic diet, epilepsy diet, low carb diet, weight maintainer diet, weight gain diet, anti-Candida diet, food allergy/intolerance rotation diet, elimination diet, hypertension diet, cardiovascular disease diet, kidney disease diet, etc.

.