In Ayurveda the human is considered to be made and nourished by the Ahara. The Varna (body colour), Prasada (lusture), Sauswarya (proper speech), Pratibha (wisdom), Medha (memory and intellect), Tushti (feel of satisfaction) and Sukha (pleasure) all are present in ahara which reflects in human after its proper intake. This body nourishing intake of ahara is called as Patthyakara Ahara. Ayurveda has mentioned different types of ahara dravya and ahara kalpana for several diseases. It varies by the type and condition of disease. In this paper the scientific evaluation of ahara and its various annaapana kalpana (Diet) mentioned by Ayurveda in Prameha (Diabetes mellitus) has been presented on the basis of Ayurveda and modern science.