Doctors are most convinced by research when it is controlled and prospective and interventional; ;in other words a randomized clinical trial. They are expensive to conduct, but we manage to do them when there are huge profits at stake for pharma companies and device makers. But the potential for better health and lower healthcare costs is much greater for a lifestyle intervention like plant-based nutrition than for yet another monoclonal antibody that gives and extra 3 months of life to somebody with Stage IV cancer. We need to be putting the resources into the critical questions of nutrition and health. We have enough evidence from observational studies and very small interventional studies to justify a large multi-center study that lasts 10 years.