Charles Stull MS RD - The dietary demands of MMA fighters; sure, they're grumpy when they diet. The Ultimate Fight Championship Performance Institute. BIO: Mr. Stull is the Director of Nutrition at the UFC Performance Institute in Las Vegas. Charles Hu Stull joined Ultimate Fighting Championship (UFC) Performance Institute as the Performance Nutrition Manager in 2018. Prior to working at the UFCPI, Charles Stull was the sports dietitian for the UCLA Athletics program. Over the past 5+ years as a sports dietitian, Charles has worked with combat sports athletes (MMA, Muay Thai, Boxing) and athletes in professional organizations such as the NFL, LPGA, and USOPC. Charles was also a DI swimmer at American University and carries a seasoned Muay Thai career with over 15 years of competitive experience.