“UMZU also bills him as a microbiome expert, based on his claims to be the first person to complete the Duke University neuroscience course in three years, and to have cured a brain tumour with nutrition, supplements and exercise. A now-deleted page on Walker’s personal website claims that his passion for health began when he performed an illegal bladder stone surgery on a man in Mexico at the age of 16.” Wired: They wanted big balls. This startup said it could help. (Nuts.)