The doshas are not exactly body types. The doshas are the three bodily humours that make up one's constitution. They are Vata, Pitta and Kapha.
It's not easy to classify a person as just belonging to one dosha. Most people are a combination of doshas. The theory is that good health is a result of balance among the doshas and ill health is a result of imbalance. Therefore, all treatments and therapies are prescribed according to your doshas and their balance.