Modelling as a profession was first established in 1853 by Charles Frederick Worth, the father of haute couture. Types of modelling include: fashion, glamour, fitness, bikini, fine art, body-part, and commercial print models.
Cara Delevingne works out with a trainer, James Duigan (He has also trained some other hot bodies like Elle Macpherson, Rosie-Huntington Whiteley, etc). To get a body like Cara, he advises to include oily fish and chicken into the diet to getting a good butt. Caffeine intake should also be degraded to get good sleep. Try to remove the sugar intake completely from the diet. If it is not possible, make sure to eat the sugar at the end of the meal to prevent the unnecessary blood-sugar peaks.