Ayurveda stresses a lot on the role of diet in maintaining good health and preventing onset of diseases. According to the philosophy of Ayurveda, health is not just maintained by taking a balanced diet but it depends on various factors like: constitution or prakriti of an individual, digestive power or agni, taste or rasa of the food item, heating or cooling energy of food or veerya, and post-digestive (metabolic) effect or vipaaka.

Constitution Or Prakriti
The inherent constitution or prakriti of an individual consists of one or more of the doshas i.e. the vaata, pitta and kapha. This determines which type of food helps the person in promoting health and nutrition and which are not conducive for the same.

Digestive Power Or Agni
The digestive power or agni is also based on the balance of the doshas in the body. Any imbalance leads to disorder of digestion and metabolism of food.

Agni is of 4 types:-
1.Vishama Agni:. Due to vaata dosha, the gastric fire becomes vitiated, causing irregular appetite, indigestion and gas. Emotionally, this can result in anxiety, insecurity, fear and neurological or mental problems.
2. Teekhna Agni: Pitta dosha is responsible for this type of disorder. It may cause hyper-metabolism, hyperacidity, heartburn and hypoglycemia leading to inflammatory diseases.
3.Manda Agni: This is due to excess kapha condition, leading to slow metabolism, overweight, allergies and congestive diseases.
4. Sama Agni: This type of agni is the result of balanced tridoshas. A person having this type of agni can eat almost any type of food without difficulty. Digestion, absorption and elimination are very normal for such a person.