Dean Ornish's claims of increased mortality and cancer in meat-eaters are based on correlational epidemiology, not interventional trials.

“now the problem with this is this is the kind of stuff that just gets me so riled up because this is epidemiology that he's citing it's not an interventional trial and I've talked about this time and time again on my podcast that what he's referring to our specific Western cohorts of people who are asked about meat consumption and then surveyed for health outcomes and the researchers are noting a correlation without being able to comment on causal effect or causal connection so he's really using epidemiology irresponsibly in my opinion when he's talking about this”