Astanga Hrudaya a classical Ayurveda text that starts with the secrets of the healthy life says following Ayurveda strictly makes you healthy for 100 years.
आयु: कामायमानेनधर्मार्थसुखसाधनम्।आयुर्वेदोपदेशेषुविधेय: परमादर: ॥
|| AstangaHrudaya Sutrastana 1st chapter ||
The purpose of life is to attain Dharma (the path of righteousness), Artha (earning resources in ethical way), Kaama (fulfilling ones desires) and Moksha (achieving Salvation), which can be achieved only with a long healthy life. This can be attained by following the guidelines in Ayurveda with utmost respect.