Balance and Harmony of the Three Doshas
When the three Doshas are well harmonized and function in a balanced manner, it results in good nourishment and well-being of the individual. However, when there is imbalance or disharmony within or between them, it will result in elemental imbalance, leading to various kinds of ailments.
The Ayurvedic concept of physical health revolves round these three Doshas and its primary purpose is to 
help maintain them in a balanced state and thus to prevent disease. This hum oral theory is not unique to the ancient Indian Medicine: The Yin and Yang theory in Chinese medicine and the Hippocratic theory of four humors in Greek medicine are also very similar.
The Qualities of the Three Doshas:The three Doshas possess qualities and their increase or decrease in the system depends upon the similar or antagonistic qualities of everything in gusted.
Vata is: dry, cold, light, mobile, clear, rough, and subtle.
Pitta is: slightly oily, hot, intense, light, fluid, free flowing, and foul smelling.
Kapha is: oily, cold, heavy, stable, viscid, smooth, and soft.
Both Vata and Pitta are light and only Kapha is heavy.
Both Vata and Kapha are cold and only Pitta is hot.
Both Pitta and Kapha are moist and oily and only Vata is dry.
Anything dry usually increases Vata, anything-hot increases Pitta and anything heavy, Kapha.
Puffed rice is dry, cold light and rough - overindulgence in puffed rice therefore is likely to increase Vata in the over indulger.
Mustard oil is oily, hot, intense, fluid, strong smelling, liquid, and increases Pitta in the consumer.
Yoghurt, which, being creamy, cold, heavy, viscid, smooth and soft is the very image of Kapha, adds to the body's Kapha when eaten.
All Five elements, as expressed through Vata, Pitta and Kapha, are essential to life, working together to create health or produce disease. No one dosha can produce or sustain life - all three must work together, each in its own way.