Despite claims by the World Health Organization (WHO) that eating processed meat causes colon cancer and red meat probably causes cancer, the observational data used to support the claims are weak, confounded by multiple unmeasured factors, and not supported by other types of research needed for such a conclusion. Although intervention studies are designed to test the validity of associations found in observational studies, two interventions of low-fat, low-meat diets in volunteers that failed to find a benefit on cancer were not considered in the WHO decision.
It is likely that the association of red-meat consumption with colon cancer is explained either by an inability of epidemiology to detect such a small risk or by combinations of other factors such as greater overweight, less exercise, lower vegetable or dietary fiber intake, and perhaps other habits that differentiate those who eat the most meat from those who eat the least.

https://www.peak-human.com/post/dr-david-klurfeld-on-meat-not-causing-cancer-bogus-vegetarian-scientists-and-balanced-nutrition SCROLL down for show notes!

He was on the World Health Organization working group to decide if meat causes cancer in 2015 with a bunch of vegetarians and vegans and says it was the most frustrating professional experience of his life

There were 22 scientists - half of which were epidemiologists

They claimed they used 800 studies but they actually only used 18

There was a group of people that were strongly against the vote

He thinks a number of the people made up their minds before they even arrived

National Cancer Institute study with 900 people split into 2 groups who had an intestinal polyp removed on a colonoscopy. One group told to eat whatever they want, one group was assigned a “healthy” diet low in red meat and processed meat, high in fruits, vegetables, and whole grains. 3 years later the risk to get a 2nd polyp was exactly the same in both groups. The emission of red and processed meats did nothing.

Then came the Women’s Health Initiative - largest nutrition study in history. 9 years of a low fat diet compared to a control - again, no difference in risk for colon cancer

So they threw out the 2 studies that were actually scientifically controlled on humans, none of the animal studies showed any problem with meat, and they're left with epidemiology and mechanistic studies they CANNOT show causation

One of the members of the working group did a study feeding mice bacon and also an agent to induce cancer and actually found the bacon diet reduced precancerous lesions!

They relied on one study that fed mice blood sausage at 3 times the normal dose of protein and the diet had a calcium deficiency - only then was

The report on that 2015 decision finally came out this summer and he has no idea why or if they omitted those studies he brought up

He mentioned to a staff member of the WHO that he thought people on the working group should declare that they are a vegetarian as a conflict of interest - she laughed and said she was a vegetarian and they changed the subject

Being a vegetarian, in his view, is far more of a conflict of interest than who funds you - it's a more deep-seated belief

He estimates ¼ to ⅓ of the committee making the decision against red meat were vegetarians