So in 2019, he launched Simple, an AI-powered health coaching app that helps people lose weight. Avo today handles more than 100,000 coaching conversations a day and processes nearly 300,000 daily meal logs, Prytkov said. Although the coaching premise of the app has remained unchanged, the rise of LLMs has been a boon to personalization. Eventually, he plans to expand beyond weight loss and make a health app that can help with sleep, stress, and movement. “Our vision is to become the Duolingo of health,” Prytkov said.