Why You should Eat Meat: My Appearance on the Joe Rogan Experience

On Sept. 27, my debate with Dr. Joel Kahn on the Joe Rogan Experience on the merit of including meat in a healthy diet lasted almost four hours. There are very few well-structured debates on this topic, and Joe did a great job of facilitating a lengthy discussion on such a controversial topic.

I’d certainly encourage all of you to watch or listen to the recording, but if you don’t have a chance to listen to it all, I’ll provide a summary of the highlights in this article.

You can also check out “Why Eating Meat Is good for you,” the cornerstone page that we put together in preparation for the debate. It outlines my key arguments and contains links to relevant blog articles and studies categorized by topic.

Background and Introductions

For those who don’t know him, Dr. Kahn is a 42-year vegan who attended the University of Michigan medical school. He also did training in internal medicine and cardiology before opening a preventive, plant-based cardiology practice in Michigan.

Of course, as many of you know, I was a macrobiotic vegan myself for many years, and a vegetarian for quite some time as well. When i was traveling around the world and became sick, it led me to question many of my earlier beliefs about vegetarianism and veganism and ultimately led me to reincorporate meat in my diet.

There Are Serious Problems with Epidemiological Research

To kick things off, we jumped right into the problems with nutritional epidemiology. Randomized clinical trials are incredibly expensive and, in many cases, impractical, so we’re left with observational studies that look at a certain group of people and try to draw inferences from their behavior about associations with disease.

I laid out the three biggest problems with nutritional epidemiology research.

Data Collection

Most observational studies employ “memory-based assessments” (i.e., questionnaires), which rely solely on a person’s recollection of what they ate.

The Healthy-User Bias

When someone engages in a behavior that’s perceived as unhealthy, they are more likely to engage in other behaviors that are perceived as unhealthy and vice versa.

Low Relative Risks

In nutrition, relative risks are often so low that they are indistinguishable from chance:

In fields outside of nutrition, nobody bestfootmassager.net would consider an increase in risk less than 100 percent (a doubling) to be anything worth paying attention to.

Dr. Kahn contended that if we throw epidemiology away, we throw away about 80 percent of nutrition research. Since we can’t do the randomized controlled trials, we’re really left with basic science and studies of centenarians in blue zones like Loma Linda, California.

I certainly don’t think we should throw out epidemiological research, but we should understand the limitations and look at the findings with a critical eye.

No, Vegetarians and Vegans Don’t Live Longer

This led to a discussion of lifespan among those following different diets. I pointed out that there are eight major studies to date that have compared lifespan in vegetarians and vegans and omnivores, only five of which did a good job controlling for the healthy-user bias. Four studies sought to compare vegans and vegetarians against health-conscious omnivores, as opposed to the general population. The fifth study found did not select health-conscious omnivores as a comparison group, but it did a much better job controlling for potential confounding factors than most observational studies do.

They found that both groups had a longer lifespan than the general population, but there was no difference in lifespan between the groups. Several meta-analyses that consider all of the available studies have confirmed this finding. (1) For more information, see my article “Do Vegetarians and Vegans Live Longer than Meat Eaters?”

Is There a Connection between Red meat and Cancer?

Dr. Kahn immediately turned to the 2015 World Health Organization (WHO) report that found an association between red meat and cancer. He argued that even though the differences are small, 50,000 people could potentially avoid colorectal cancer by avoiding red meat. Furthermore, with newer statistical methods, we can better isolate the effects of animal protein in observational studies.

I pointed out that the WHO report found only an 18 percent increased risk of cancer from eating processed meat, and a two percent increased risk from eating unprocessed red meat. This means that 5.3 people of 100 eating more processed meat would develop cancer, vs. 4.5 people of 100 eating less processed meat. As many epidemiologists have suggested, these tiny differences are difficult to distinguish from chance in observational studies.

What’s more, there are several other studies that have shown no relationship between unprocessed red meat consumption and cancer. For an excellent review of the role of meat in a healthy diet, I suggest this article by David Klurfeld, the National Program Leader for Human Nutrition in the Agricultural Research Service of the U.S. Department of Agriculture and an associate editor at the American Journal for Clinical Nutrition.

We next discussed several mechanisms for how processed meat might contribute to cancer risk, with N-nitroso compounds, heterocyclic amines, heme iron, Neu5Gc, and TMAO being the most highly cited. However, these often don’t consider the context of the meat consumption. For instance, chlorophyll-rich green vegetables prevent myoglobin form being turned into nitro compounds. Similarly, certain spices and marinades have been shown to reduce the formation of heterocyclic amines.

Given this, not surprising that in all the studies of the relationship between red meat and cancer that controlled for vegetables, a greater increase was seen in people not consuming vegetables. (2) Vegetable consumption seems to confer a protective effect against any potential harm that may come from eating meat. (3)

Dr. Kahn agreed with this and encouraged listeners to at the very least eat vegetables with their meat.

Does Saturated Fat Increase your Blood Cholesterol?

We next moved to saturated fat. Dr. Kahn claimed that basic science has shown that when you eat foods rich in saturated fat, you reduce the receptors on the liver that take cholesterol out of the blood. Cholesterol stays in the blood and eventually leads to atherosclerosis. He cited a 1997 paper that analyzed the results of 395 metabolic studies where they changed the diet and measured the response to cholesterol: (4)

You add saturated fat, cholesterol skyrockets.

I took a brief look at this paper after the debate, and they did find an increase in blood cholesterol when saturated fat was replaced with complex carbohydrates, but the difference was only 9.4 mg/dL reduction in LDL. It also resulted in a reduction of HDL of 1.8 mg/dL. Many of these metabolic ward studies were also short-term feedings studies that lasted less than a month, and did not measure clinical outcomes. (5)

Dr. Kahn further argued that every major health agency in the world recommends limiting saturated fat intake. I reminded him that these agencies are often behind the times, and:

… the history of science is really the history of most scientists being wrong about most things most of the time.

In the last two revisions of the USDA dietary guidelines, they removed restrictions on total fat and cholesterol-and I wouldn’t be surprised if saturated fat is next.

The most important question, however, is not whether eating saturated fat increases blood cholesterol levels. It’s whether eating saturated fat increases the risk of heart disease. After all, if saturated fat increases blood cholesterol but doesn’t increase the risk of heart disease, why should we care about cholesterol going up?

19th October 2018/by wp_admin_project