(1) (nutrition) The food and drink consumed by an individual or group
(2) The controlled or restricted consumption of food or drink for a particular purpose, e.g. to manage body weight
In nutrition, diet refers to the food and drink that is regularly consumed by an individual (or a group). During a particular therapy of a disease or management of a particular health condition, the diet may be controlled, i.e. one that meets the physical needs of an individual. For instance, the diet of a diabetic person may be restricted to a selection of food and drinks that help manage the level of blood sugar. The diet recommended for patients with diabetes includes plenty of fibrous, non-starchy fruits and vegetables. Starchy foods are rich in carbohydrates that consuming a large portion may result in increased sugar level in blood.
Apart from health reasons, diet may also vary according to other factors, such as religious beliefs and personal preferences. Humans in general take an omnivorous diet. However, some people tend to be selective to certain food types. This selective dietary behaviour led to various diet types, which can be classified based on the kind of food that are habitually or preferentially consumed: