How "Red Meat Causes Diabetes" Becomes a Headline

 

You may have seen a headline a time or two about red meat consumption being linked to diabetes, or about red meat appearing to be a prime driver of the condition. Such a headline is circulating in some corners of the media as I write this, which explains the timing of this post.¹

But how does that happen? How does that headline come to be, and how have scientists determined that red meat may be to blame for the rapid rise in diabetes? A rise, one must note, that in America has occurred alongside a significant decrease in red meat consumption.

 

Beef consumption: USDA consumption trends²; Diabetes rates: CDC diabetes statistics³

 

Below I lay out a chain of events that leads to multiple rounds of authoritative-sounding proclamations on the diabetic dangers of meat consumption.

Here’s how it happens:

 

Shoddy Scientific Strategies

We start, for example, with this study from 2011 that “evaluated the association between unprocessed and processed red meat consumption and incident T2D in US adults.”⁴ The researchers went about this task by surveying people on what they eat (and other lifestyle habits) and assessing them for disease. Then they divided people into five quintiles of red meat consumption and noted that the group eating the most red meat was noticeably more likely to have diabetes than the group that ate the least. Voila! – red meat consumption is associated with diabetes.

And in a sense, that statement is true. People who have diabetes seem to eat more red meat than people who don’t. But the methods used to make this determination, the decision to publish a paper claiming as such, and the common mainstream reporting of the red meat-diabetes link seem to fall something short of honest and factual. To be somewhat fair to the reporters who write or comment on such topics, they’re only repeating what they’ve been told by often respected institutions (Harvard, for one) and clearly aren’t reading these papers with any interest in the underlying methods and findings.^5–7 So lets do that for them…

The huge problem (there are others, but we’ll keep this as straightforward as we can) with this study is simple. They found that those who ate the most red meat, and had the highest rates of diabetes, consumed about 740 calories more each day than those who consumed the least red meat. They then proceeded to break down this calorie consumption by food group. What you see below is each category the researchers chose to measure and the number of servings the high-meat group ate compared to the low-meat group. Obviously more red meat, and also fewer whole grains, fruits and veggies, etc. I’ve used USDA serving recommendations to best estimate the caloric cost of each of these differences.

 

Item	Servings +/-	Calories +/-
Red Meat	+1.9	+ 400
Fruit/Veg	-1.0	-60
Egg	+0.3	+25
Soft Drinks	+0.3	+30
Dairy	+0.4	+75
Nuts	0	0
Potato	+0.4	+40
Fish	-0.25	-50
Poultry	-0.1	-10
Alcohol	+0.4	+75
Whole Grains	-3.0	-225
Total Calculated	--	+300
Actual Calories	--	+740

 

So the study accounts for consumption of red meat, poultry, fish, dairy, eggs, whole grains, potatoes, nuts, fruits, vegetables, alcohol….but comes up more than 400 calories short of explaining the diet of the meat-eating group. Which foods are missing? Well, there are two huge ones – sugar and refined grains. They don’t measure or list the amounts of these foods being consumed, but by process of elimination we can be quite sure the meat-eaters are also consuming multiple hundreds of calories more per day of these items.

 

The Effects of the Calories is What Matters

Why is this so important? Because diabetes is a disease of insulin resistance. The cells of your body have a tolerance, so to speak, for the storage hormone insulin. A person becomes insulin resistant when the cells don’t respond to insulin the way they used to, which causes blood sugar to be excessively elevated for long periods of time. This in a nutshell is diabetes. And likely the best way to become insulin resistant is to force your body to deal with chronically elevated insulin levels. You can think about it like any other tolerance in this sense – the first cup of coffee you ever drank had you wired, now it takes two to stay awake. In much the same way, cells become dulled to the effects of excess insulin.

Sugar and refined grain consumption is so important because carbohydrates are the primary macronutrient that raise levels of insulin in the blood. Protein has a milder effect, while fat has no effect whatsoever. So while red meat is extremely low on the list of foods that raise insulin levels, sugar and refined grains are about as high as it gets.

So what the researchers claim they found is that “red meat consumption was positively associated with the risk of T2D.” What they actually found was that red meat + sugar + refined grain consumption was positively associated with diabetes. I won’t speculate (yet) as to why they chose to publish a paper focusing on the only one of those items that has a negligible impact on insulin and blood sugar.

(I’ll note here that many interventional trials, in which researchers actually control a subject’s diet rather than surveying them afterwards, have demonstrated the capacity for high-fat diets to reduce insulin levels, reduce blood sugar, and improve diabetic complications.^8–18 These studies never seem to become headlines.)

 

Healthy User Bias

Let’s expand further – why are people who eat more red meat also eating more sugar and developing diabetes? This is a good time to briefly discuss something called “healthy user bias.” Basically, people who want to be healthy tend to do things they believe are healthy. As most people in developed countries have been hearing their entire lives that red meat and saturated fat aren’t so great, it ends up being the unhealthy ones who are willing to throw caution to the wind and consume them anyway. You can see this in the study above – the meat eaters drink more alcohol, they exercise less, they’re significantly more likely to smoke, and, of course, they eat more sugar and processed grains.

Now, the researchers make adjustments for the drinking, smoking, and sedentary lifestyle in order to minimize or eliminate the effects these factors could have on the results. But they make no effort whatsoever to adjust for sugar/refined grain consumption or its two major effects – elevated blood sugar and elevated insulin levels. This point is truly beyond comprehension and renders an observational study like this little more than an absurdity. You simply cannot claim to assess the risk of diabetes while taking deliberate steps to ignore arguably the single greatest lifestyle factor that influences that risk.

But, the link between red meat and diabetes is indeed what they chose to report, so that is what filters out into the public consciousness. It becomes “known” that red meat could cause diabetes. Which leads us to our latest headline making the news, misleading the public in a similar manner.

 

Expanding on the Previous Shoddy Science, with More Shoddy Science

“Refined carbs and red meat driving global rise in type 2 diabetes, study says”¹

The headline might make you think this claim was based on elaborate trial, or at least a painstaking assessment of the dietary choices of diabetic patients. But in reality, its based on nothing more than the previous set of highly questionable papers like the one just discussed above. The researchers here made no assessment whatsoever as to what might cause diabetes. They simply searched for studies like the one above and used them to form assumptions about which foods do cause diabetes. Then they attempted to figure out how much each pre-determined cause might contribute to the millions of cases of diabetes around the world.

Broadly speaking, the process these researchers used to determine the respective contribution of these food groups to diabetes risk was as follows:

1. Find a bunch of observational papers like the one discussed above that link various food groups to diabetes, and decide which were worthy to include
2. Use national datasets to calculate the consumption of these various food groups and compare it to the researchers own recommendations (based reportedly on government and health agency guidelines, plus the aforementioned studies) for how much people “should” be consuming of each
3. Calculate the degree of deviation between the actual consumption in these populations and the recommended amount
4.  Compare the degree of deviation for each food group to rates of diabetes in the various populations, and attempt to calculate the degree of responsibility each deviation has on the incidence of diabetes

To be clear, this paper did not measure the dietary patterns of diabetics. It did not attempt to measure all possible dietary trends. It simply decided ahead of time which dietary patterns might cause diabetes and tried to rank them using national consumption data.

This is how you end up with the surprising result that “insufficient yogurt intake” is the world’s 5^th leading cause of diabetes. I would bet an extremely large sum of money that it is not. But these researches found some piece of epidemiology suggesting that people who have diabetes eat less yogurt than those who don’t, and so set their threshold for optimal consumption nice and high – four times higher than the average person consumes in a day. Obviously, most people (and most diabetics) don’t hit this arbitrary threshold for yogurt consumption, so you end up with a significant deviation from their recommended amount. Thus, they end up assigning a reasonable proportion of all diabetes risk specifically to the insufficient consumption of yogurt.

Excess consumption of refined grain is ranked first because people tend to consume a lot of it and because they (correctly!) set the optimal intake at zero. But they also set the threshold for red meat consumption very low, based entirely on “evidence” like that discussed above. How low? Roughly half an once of red meat per day. Similar to the yogurt example, it is inevitable that most populations are consuming more than this amount, and so it shows up a significant deviation from the researchers pre-determined optimal amount.

Sugar Actually Does Affect Your Health

The eleven dietary trends chosen were as follows: Too much red meat, processed meat, potatoes, refined grain, soda, and fruit juice, and not enough fruit, vegetables, whole grains, yogurt, and nuts. Once again, despite diabetes being a condition diagnosed by the presence of excess blood sugar, sugar itself was not even considered as a possible culprit in any single case of the disease.

Why did these researchers, much like the ones in the first study, choose to avoid sugar in their assessment of diabetes risk? I have no idea. I do know this study was authored by many of the same people who recently created a new “food compass score” that found Frosted Mini-Wheats to be one of the healthiest foods a person could eat, so this is hardly the first time they’ve ignored sugar.¹⁹ Nor are they the only researchers to do this. Skipping right past sugar consumption is a huge, huge problem in so many observational nutrition papers. And because healthy user bias dictates that sugar and meat consumption often correlate, the result is frequently that meat is made to look dangerous. Which in turn further magnifies the healthy user bias, and so on.

This is where we blur the line between objective and opinion. I don’t know why the authors of these papers make the choices they do. But I can say with complete certainty that they are making choices that avoid implicating sugar in a disease quite literally defined by elevated blood sugar. I think this is probably deliberate. I think funding from sugar and grain corporations influence their choices. I think they are doing this to pass the blame somewhere else. I think they are doing this to push an anti-meat narrative.

Regardless of the reasons, the result is a mainstream message that the consumption of red meat, a food that has no real effect on blood sugar and little effect on insulin, places one at greater risk for diabetes. And that simply isn’t supported by physiology, disease trends, or the available scientific evidence.

1.               Refined carbs and meat driving global rise in type 2 diabetes, study says | CNN. Accessed April 25, 2023. https://www.cnn.com/2023/04/17/health/rise-type-2-diabetes-global-wellness/index.html

2.               USDA ERS - Food Availability and Consumption. Accessed April 25, 2023. https://www.ers.usda.gov/data-products/ag-and-food-statistics-charting-the-essentials/food-availability-and-consumption/

3.               Long-term Trends in Diabetes.

4.               Pan A, Sun Q, Bernstein AM, et al. Red meat consumption and risk of type 2 diabetes: 3 cohorts of US adults and an updated meta-analysis. The American Journal of Clinical Nutrition. 2011;94(4):1088-1096. doi:10.3945/ajcn.111.018978

5.               Writer APHS. Clearing up the confusion over red meat recommendations. Harvard Gazette. Published November 8, 2019. Accessed April 25, 2023. https://news.harvard.edu/gazette/story/2019/11/clearing-up-the-confusion-over-red-meat-recommendations/

6.               What’s the beef with red meat? Harvard Health. Published February 1, 2020. Accessed April 25, 2023. https://www.health.harvard.edu/staying-healthy/whats-the-beef-with-red-meat

7.               Avenue 677 Huntington, Boston, Ma 02115. Red meat linked to increased risk of type 2 diabetes. News. Published August 10, 2011. Accessed April 25, 2023. https://www.hsph.harvard.edu/news/press-releases/red-meat-type-2-diabetes/

8.               McKenzie AL, Hallberg SJ, Creighton BC, et al. A Novel Intervention Including Individualized Nutritional Recommendations Reduces Hemoglobin A1c Level, Medication Use, and Weight in Type 2 Diabetes. JMIR Diabetes. 2017;2(1):e6981. doi:10.2196/diabetes.6981

9.               Westman EC, Yancy WS, Olsen MK, Dudley T, Guyton JR. Effect of a low-carbohydrate, ketogenic diet program compared to a low-fat diet on fasting lipoprotein subclasses. International Journal of Cardiology. 2006;110(2):212-216. doi:10.1016/j.ijcard.2005.08.034

10.             Yancy WS, Olsen MK, Guyton JR, Bakst RP, Westman EC. A Low-Carbohydrate, Ketogenic Diet versus a Low-Fat Diet To Treat Obesity and Hyperlipidemia. Ann Intern Med. 2004;140(10):769-777. doi:10.7326/0003-4819-140-10-200405180-00006

11.             Garg A, Grundy SM, Unger RH. Comparison of Effects of High and Low Carbohydrate Diets on Plasma Lipoproteins and Insulin Sensitivity in Patients With Mild NIDDM. Diabetes. 1992;41(10):1278-1285. doi:10.2337/diab.41.10.1278

12.             Gower BA, Chandler-Laney PC, Ovalle F, et al. Favourable metabolic effects of a eucaloric lower-carbohydrate diet in women with PCOS. Clinical Endocrinology. 2013;79(4):550-557. doi:10.1111/cen.12175

13.             Yuan X, Wang J, Yang S, et al. Effect of the ketogenic diet on glycemic control, insulin resistance, and lipid metabolism in patients with T2DM: a systematic review and meta-analysis. Nutr Diabetes. 2020;10(1):1-8. doi:10.1038/s41387-020-00142-z

14.             Gu Y, Yu H, Li Y, et al. Beneficial Effects of an 8-Week, Very Low Carbohydrate Diet Intervention on Obese Subjects. Evidence-Based Complementary and Alternative Medicine. 2013;2013:e760804. doi:10.1155/2013/760804

15.             Meng Y, Bai H, Wang S, Li Z, Wang Q, Chen L. Efficacy of low carbohydrate diet for type 2 diabetes mellitus management: A systematic review and meta-analysis of randomized controlled trials. Diabetes Research and Clinical Practice. 2017;131:124-131. doi:10.1016/j.diabres.2017.07.006

16.             Huntriss R, Campbell M, Bedwell C. The interpretation and effect of a low-carbohydrate diet in the management of type 2 diabetes: a systematic review and meta-analysis of randomised controlled trials. Eur J Clin Nutr. 2018;72(3):311-325. doi:10.1038/s41430-017-0019-4

17.             Nielsen JV, Joensson EA. Low-carbohydrate diet in type 2 diabetes: stable improvement of bodyweight and glycemic control during 44 months follow-up. Nutrition & Metabolism. 2008;5(1):14. doi:10.1186/1743-7075-5-14

18.             Unwin D, Unwin J, Crocombe D, Delon C, Guess N, Wong C. Renal function in patients following a low carbohydrate diet for type 2 diabetes: a review of the literature and analysis of routine clinical data from a primary care service over 7 years. Current Opinion in Endocrinology & Diabetes and Obesity. 2021;28(5):469-479. doi:10.1097/MED.0000000000000658

19.             Mozaffarian D, El-Abbadi NH, O’Hearn M, et al. Food Compass is a nutrient profiling system using expanded characteristics for assessing healthfulness of foods. Nat Food. 2021;2(10):809-818. doi:10.1038/s43016-021-00381-y