Meat is bad for you. Wait, it’s OK

Contrary to decades of work, researchers from Dalhousie and McMaster Universities recently found that red meat, including bacon, is not harmful. It wasn’t a new study but rather a “study of studies,” a meta-analysis of existing studies.

image: Foreman Grill Recipes

It was a perfectly flawed study. Perfect because it offered a veneer of the scientific method; flawed because of what it didn’t include.

It didn’t include studies that found the opposite of their conclusion. Those well-researched studies found a link between meat consumption and coronary heart disease, heart attack, Type 2 diabetes, cardiovascular death and all-cause mortality. That’s quite an exclusion.

As well, the researcher’s conclusions were contrary to those of the World Health Organization, the Canadian Cancer Society, the American Institute for Cancer Research, and the American Heart Association. Their findings also diverged from Canada’s new Food Guide which suggests eating less animal protein.

Why did the researchers not include studies that concluded the opposite of their report? They weren’t funded by the cattle or pork industry. The reason that they didn’t include the studies was technical. The self-selected 14 member panel decided that these findings were not of sufficient quality.

What they did include is suspect. For example, they included one trial that dominated their analysis; a trial involved almost 49,000 women. But that trial was designed to examine dietary fat intake, not meat intake says nutritionist Leslie Beck (Globe and Mail, October 2, 2019).  It seems to me that a study purporting to investigate the relationship between meat consumption and health shouldn’t include fat consumption.

And the researcher’s findings were flawed in another way. They did not distinguish between the consumption of red meat and processed meat, despite evidence that processed meat such as bacon is more harmful.

It’s not surprising that their study should come to the conclusion that it did. Obviously, what’s included will determine the outcome.

The researchers at Dalhousie and McMaster Universities were exhaustive in a peculiar way. They were exhaustive in the number of findings: they conducted not just one review but five.

Three of the reviews analyzed more than 100 observational studies involving more than six million participants. These types of studies link associations between consumption and health by following people for decades to see if participants who became ill or died.

Another of the five reviews analyzed randomized controlled trials, studies that show cause and effect of eating more or less red meat.

The researchers were thorough enough to appear scientific but blind in excluding accepted knowledge. They couldn’t see the forest for the trees.

The authors acknowledged their lack of confidence in their data. They conceded that their recommendation was weak but judging by the headlines they received, you wouldn’t know it.

Finally, studies on groups of people don’t necessarily predict outcomes for individuals. Leslie Beck says:

“A large body of evidence suggests that a high intake of red and processed meat increases the risk of ill health. I acknowledge that the risk on an individual level may be small, and that it’s your overall diet that matters most when it comes to health, not one food.”