Vinod Khosla. Steve Jennings/Getty images for TechCrunchAfter passing on the startup several years back, Vinod Khosla made an investment in HealthifyMe.Insider was told by a venture capitalist that he was impressed with the app's use AI for health and fitness.Khosla Ventures led the $75 million round of funding for HealthifyMe in July.Check out more stories from Insider's business page.Vinod Khosla, a billionaire investor, recently invested in an Indian app for health and fitness called HealthifyMe. Insider got an exclusive interview with Khosla Ventures boss Vinod Khosla about why he invested millions in the startup, even though he had only passed on it a few years back.HealthifyMe is a combination of human coaches and artificial intelligence. It offers nutritional advice, exercise classes, and diet plans to approximately 25 million users. Khosla Ventures was co-lead investors in HealthifyMe’s Series C funding round. The company raised $75 million last month. HealthifyMe now has more than $100 million in funding from investors such as Unilever Ventures, Elm, an IT security company that is owned by Saudi Arabia's Public Investment Fund.Khosla was attracted to the startup's large market and its aim of making people healthier and more active. He stated that the greater the problem, the greater the opportunity. "Obesity is a major problem, as well as health."He said that HealthifyMe's mission was "good for society, good business."Khosla was most excited by the app that harnesses AI to provide tailored nutrition advice based on user's specific health conditions and local cuisine. He said that without this technology, the company would need to hire a large number of nutritionists making it less affordable and scalable.HealthifyMe's AI use gives it a better growth trajectory than a typical diet company. The app also trumps traditional dieting and weight loss books because it can update its advice on the basis of the most recent scientific research.Insider was told by the venture capitalist that he is looking to invest in entrepreneurs with visions of disrupting large markets. He mentioned Square CEO Jack Dorsey who founded his payments company with the aim of turning small businesses around. Khosla is particularly fond of entrepreneurs who see their dreams become a reality as they grow and expand their businesses.He said that HealthifyMe has "continued expanding their vision of the market size and what they can achieve with AI."Insider was told by Khosla that he had met Tushar Vashist, HealthifyMe CEO and cofounder, a few years back. However, he wasn't sure the entrepreneur would deliver on his promises. He said, "Silly of you."Although the investor did not get on board at first, he said that "the boat came around again".Continue reading: Warren Buffett and Vinod Khosla are on opposite ends of investing spectrum. The legendary VC explains why valuations don’t always matter and why he doesn’t worry about market crashes or asset bubbles in an exclusive interview.