17.7 आहारः food, तु indeed, अपि also, सर्वस्य of all, त्रिविधः threefold, भवति is, प्रियः dear, यज्ञः sacrifice, तपः austerity, तथा also, दानम् almsgiving, तेषाम् their, भेदम् distinction, इमम् this, श्रृणु hear.

Commentary:
Each Every being that eats.Imam This That which is going to be described.Tesham Their Of food, etc.According to the Gunas, a mans taste for a particular food is determined. There are three kinds of food that a man can eat.All foods have different properties. Different foods exercise different effects on different compartments of the brain or the mind. A confection of sparrow, meat, fish, eggs, onion and garlic excites passion. Fruits, barley, etc., render the mind calm and serene. The nature of food greatly influences the being of a man. Man feels a desire for particular foods according to his Guna or temperament.The body is the instrument by which man accomplishes all his purposes in the world. It is the horse that takes him to his destination or goal (Moksha). Therefore it should be kept clean, strong and healthy. The body is a mould prepared by the mind for its activities. There is an intimate connection between the body and the mind. The nature and condition of the body has a vital effect upon the mind and activities. Therefore the materials or foods that build the body and the mind should be pure, wholesome, nutritious, substantial and bland.Everything in this world is threefold. The food is either Sattvic, Rajasic or Tamasic according to its,character and effect upon the body and the mind. You can find out the nature or temperament of a man from the nature of the food he takes. You can find out your own nature, whether you are Sattvic, Rajasic or Tamasic, from your predilection to particular food and then abandon the Rajasic and the Tamasic foodstuffs and take to the Sattvic diet.Why is there also a triple division in sacrifice, austerity and charity Because this threefold division is according to the nature of the Gunas. You can find out and abandon the Rajasic and the Tamasic ones and take recourse exclusively to the Sattvic ones.The practice of Krichhra and Chandrayana Vratas that produce emaciation of the body and the senses is austerity. Tapas means meditation also. It produces Brahmatejas or divine splendour and glow on the face.