Marks Daily Apple
Serving up health and fitness insights (daily, of course) with a side of irreverence.
16 Aug

Does Eating Red Meat Increase Type 2 Diabetes Risk?

If you already eat Primal, your email inboxes are most likely filling up with links to the story. Concerned mothers clutching the local paper’s “Health” section are calling (or, if they’re hip, texting). Smug vegetarian Facebook friends are posting the story on your wall, sans commentary. Yes, it’s about that time again. It’s another week, it’s another observational study by data-mining researchers hoping to establish a solid link between red meat and some chronic, horrific illness. So, what’s killing us this time? Well, considering that they’ve already done studies linking red meat to colorectal cancer, heart disease, and outright death, type 2 diabetes is next.

Here’s a link to the full study (PDF). Researchers drew on data from three large-scale dietary habit questionnaires of medical professionals to explore how red and processed meat intakes associated with the incidence of type 2 diabetes. The first set was the Health Professionals Follow-Up Study, which comprised 37,083 male physicians followed for 20 years; the second was the Nurses’ Health Study I, which included 79,570 female nurses followed for 28 years; and the third was the Nurses’ Health Study II, which followed 87,504 women for 14 years. These data were pooled with additional data from 442,101 participants in existing studies, so it was a big pile of numbers with which to work.

Sure enough, they found a link between processed meat intake and type 2 diabetes, with a smaller link between unprocessed red meat and the illness. A daily 50 gram serving of processed red meat was associated with a 51% greater risk of developing type 2 diabetes, while a 100 gram serving of fresh red meat represented a 19% increased risk. Unprocessed meat included “beef, lamb, or pork as main dish” (roasts, steaks, chops), “hamburgers” (but I’m sure they got bunless burgers, right?), and “beef, pork, or lamb as sandwich or mixed dish” (served up on coconut flour bread, no doubt). Processed meat meant “hot dogs,” “bacon,” “sausage, salami, bologna, and other processed red meats.”

To give a complete picture of the data, I’ll briefly discuss what the “heavy meat eaters” did when they weren’t eating red meat. You tell me if you notice any alarming trends that might have something to do with type 2 diabetes. Folks in the highest quintiles of meat intake were the least active and the most sedentary. They exercised the least and smoked the most tobacco. They drank more alcohol than any other quintile. They guzzled more soda and other sweetened beverages. In the high meat quintiles, folks ate 800 more calories per day than folks in the low meat quintiles. They were much heavier, too (all muscle, I’m sure). Trans fat intake was higher in the high-meat quintiles, too, as was potato intake (since these data included the years before trans fats were taken out of fast food deep fryers, I’m thinking these guys enjoyed a burger and French fry value meal on occasion). They ate the least amount of fiber from grains, indicating they probably ate the most refined grains, drank the most coffee, and ate the fewest fruits and vegetables. In short, people who ate the most red and processed meat were also the unhealthiest by both Primal and mainstream standards. And if what they were doing was actually healthy or neutral (like drink coffee and avoid fiber from grains), it wasn’t by design. These people (all health professionals, ironically) most likely didn’t particularly care about their health.

There are also variables that weren’t even considered that could have impacted the results. Added sugar, which many people heap into their coffee, wasn’t covered. They did cover the polyunsaturated fat:saturated fat ratio, but those numbers only incorporated the fat content of whole foods like nuts, meat, eggs, and dairy, not whatever cooking oils were used to fry up all that meat. So there are a couple other significant confounders.

You know how we’re always making the point that people who eat the most meat, except for us weirdo Primal types, are also the most likely to be unhealthy in other areas, to eat fast food, to be sedentary, and to smoke? Well, here’s direct evidence that this actually is the case.

And then there’s the issue of relative versus absolute risk (for a good primer on relative risk, check out Dr. Eades’ post on the subject). 51% greater risk sounds pretty awful, right? I mean, that’s over half. And when most people hear a figure like that, they take notice. They don’t really think about what the number means in terms of absolute risk, but they immediately link whatever risk factor is being highlighted to the big scary percentage figure – and the damage is done. In reality, the effect size is tiny. The absolute risk of getting diabetes was rather small for a participant of the studies mined for their data – about 7% over the course of the 14-28 year range. A 51% increase in risk bumps that up to about 10.5%, not 58%, while a 20% increase bumps risk up to around 8.4%, not 27%. I don’t fault the researchers for using statistics, because they’re totally valid, but I worry that the average person will see those big percentages and think that represents absolute risk. And then they give up their meat.

So what’s the problem with observational studies?

It’s not that there’s anything inherently wrong with an observational study. In fact, they’re extremely useful and downright necessary for generating hypotheses, but they cannot establish causality. As both Mat Lalonde and Tom Naughton consistently emphasized during their presentations at the Ancestral Health Symposium, we do science and we do our cause a disservice when we overstate the evidence drawn from an observational study. The same goes for health researchers, who to their credit usually do a good job keeping their conclusions (if they make any at all) conservative. It’s the science reporters that love definitive headlines and concrete conclusions.

“Associated with”? Ha!

“Relative risk”? Never heard of it!

“Causes”? Now we’re talking!

Check out the headlines, which range from the conservative “Red Meat Linked to Increased Risk of Type 2 Diabetes” to the bordering-on-unequivocal “Bacon ‘increases risk of diabetes.” The former hails from the Harvard School of Public Health’s PR department, which actually conducted the study, while the latter comes from the Irish Independent. It’s a perfect example of what’s wrong with science reporting. Those headlines are designed to draw you in and precondition your expectations for the content. Heck, you might not even have time for the full text, in which case you’ll be left with the idea that bacon causes diabetes. Maybe it does, maybe (probably) it doesn’t, but we can’t know from observation.

As I read the study, I was pleasantly surprised by the restraint of the authors. Sure, the science reporters took the limited evidence and ran with it, but you expect that from them. It doesn’t surprise me anymore. The actual researchers, though, seemed to make it abundantly clear that no concrete conclusions about causality could be inferred from the data analysis. They even went on to propose a few potential mechanisms, as if to suggest that, I dunno, more studies were required to establish any sort of causality. In fact, they fully and continually admitted the limitations of the study as they composed the text. Until, that is, the very last sentence of the full text:

“Therefore, from a public health point of view, reduction of red meat consumption, particularly processed red meat, and replacement of it with other healthy dietary components, should be considered to decrease T2D risk.”

In other (my) words, “Despite our repeated insistence on the limitations of observational data analyses, and the fact that both causality and biological mechanism have yet to be established and indeed cannot ever be established through an observational study such as the one described in this paper, we recommend that the public reduce their consumption of red meat. The evidence in favor of such a recommendation is weak, poor, inconclusive, and highly confounded by listed variables like sedentary lifestyles, smoking, alcohol consumption, caloric intake, soda drinking, and bodyweight, plus the variables we didn’t even consider, including the oil the meat was cooked in, the baked goods the meat was served upon, and sugar intake, but do it anyway. We’re from Harvard, by the way.”

So, in the end, should this observational study cause red meat-eaters to worry? No. The confounding variables are vast and the absolute risk is low. Plus, remember: you are not the typical meat eater. You cook your meat in good fats, you eat plenty of vegetables, you lift heavy, you walk, you enjoy life, you savor relaxation and understand the pitfalls of stress, seed oils, sugar, and sunlight deprivation. Should any observational study in the future force you screaming from your butter/red meat/full-fat dairy/deep squats/barefoot running, remember that fact. No observational study should make you fear anything – not if you’re thinking clearly, can make the distinction between relative and absolute risk, and are able to identify potential confounding variables. But it should keep you questioning things, which is exactly what we need if we’re to keep learning, growing, and progressing.

You want comments? We got comments:

Imagine you’re George Clooney. Take a moment to admire your grooming and wit. Okay, now imagine someone walks up to you and asks, “What’s your name?” You say, “I’m George Clooney.” Or maybe you say, “I’m the Clooninator!” You don’t say “I’m George of George Clooney Sells Movies Blog” and you certainly don’t say, “I’m Clooney Weight Loss Plan”. So while spam is technically meat, it ain’t anywhere near Primal. Please nickname yourself something your friends would call you.

  1. I eat a pound of red meat per meal.

    If this was true I would have lost a foot by now.

    Laws of the Cave wrote on August 16th, 2011
  2. Let’s not forget that the data from the Nurses’ Health Study is complete trash, as Chris Masterjohn has already proved:

    “Epidemiological studies about meat intake usually tell us less about the risk or benefit of eating meat and more about people’s propensity to lie about how much hamburger they eat.”

    J. Stanton wrote on August 16th, 2011
  3. “We’re from Harvard, by the way.”

    Thnaks for making me spray water out my nose onto my laptop. :-)

    Tanis MacDonald, DVM wrote on August 16th, 2011
    • ROFL!(Hey – good excuse for getting a new comp!)

      PrimalGrandma wrote on August 16th, 2011
    • I snorted my coffee when I read that line :)

      shadia wrote on August 17th, 2011
      • I watched someone snort coffee grinds up their nose once. He was saying how he’d snort anything for kicks and someone mentioned coffee and he said he’d probably snort it. I had a ziplock bag full of instant coffee in my backpack so I mentioned that and he said he was up to the challenge, sniffed up a huge line, and ended up with a really sore nose and a headache.
        I also saw someone snort nutmeg and salt and pepper, and I think he might have actually snorted ketchup too though I can’t remember for certain. I didn’t see but apparently he also smoked salt, knowing what it was.

        Animanarchy wrote on August 17th, 2011
  4. My mom gets migraine pills sometimes that cost $15 each. Such a waste! I told her that I bet her migraines are caused by inflammation or something else that can be cured by changing her diet, but no…. food can’t be a factor in these sort of things at all. Migraines just happen, right? Of course our family doctor, who says that you can eat junk like granola bars and “fruit” snacks throughout the day for satiety and be healthy eating “one healthy meal” like a pasta dinner a day, isn’t going to provide any useful information. She doesn’t look that healthy by the way. I bet she gets handouts for all the meds she prescribes. She gave my mom antidepressants, which I bet she wouldn’t need if she wasn’t on the sugar rollercoaster and if she was taking some vitamins to prevent deficiencies which causes brain chemical imbalances? Nah, multivitamins are too expensive, unlike all the cookies, crackers, chips, sugary cereals, and so on that are practically toppling out of the cupboards.
    When I was younger the doctor prescribed me a crapload of antibiotics that I now realize I never needed, with the possible exception of when I had pneumonia. “Here, drink this artificially coloured and flavoured banana medicine, it will make you all better, and have a lollipop before you go.” Holy shit eh. What kind of doctor gives sugar to little kids? Most of them!
    Two winters ago I had bronchitis and didn’t bother going to the doctor – that cleared up on its own, even though I was smoking cigarettes at the time! (Something I’ll never go back to). And I bet the main reason I got sick is because I was living in a shelter where practically every single meal was spaghetti or something else made of flour because that crap is cheap, and I was doing lots of stupid things and not sleeping enough.
    I also offered to save my mom some money by cooking up a batch of herbal brownies or something (costs me a few dollars to cure any headache naturally), which I bet would work just as well if not better with less side effects, but no such luck. She hates the idea (illegal = bad; legal = good , because altruistic angels are in charge of the legal system – I could go on for pages about that, but won’t bother) and would rather take stuff made in a lab by Big Pharma, and drink a couple beers or glasses of wine to feel good. I told my parents that over 60% of liver failures in the U.S. are determined to be caused by aceteminophen. They still went and bought more Tylenol.
    Well to each their own.
    Since going primal I haven’t had as much as a cold and I don’t think I’ve had a single headache, except the strange discomfort I get in my head when I drink too much coffee, which I attribute to a temporary increase in blood pressure in the brain. I look healthier than I used to, and with a history of lots of smoking I can still outrun my mom who’s been doing chronic cardio most of her life, so hopefully eventually the undeniable evidence will be enough to snap them out of their CW hypnosis.

    Animanarchy wrote on August 16th, 2011
    • P.S. I know I had bronchitis because I eventually saw a doctor in rehab (a check-up there was required) when the bronchitis was pretty much gone and after listening to my breathing he told me I had a slight case of it, but didn’t prescribe anything since it was going away.

      Animanarchy wrote on August 16th, 2011
    • I saw a lady in the store the other day with her brandnew spankin baby. The baby was so tiny, it still was purple and wrinkled.
      The Lady looked extremely exhausted, holding the baby in 1 arm, and a bottle of childrens Nighttime Tylenol in the other hand.

      I almost said something…or slapped her…

      Primal Palate wrote on August 16th, 2011
  5. How about this research linking dietary fat to diabetes?

    Dave Sill wrote on August 16th, 2011
  6. A grass fed ribeye stake is so much more than the equivalent protein,fat and vitamins from other sources, and It makes you feel fantastic all day long.

    It’s also possible that these people demonstrating the higher risk link are quite sick from other causes and the meat is having a protective effect.

    Last time I checked spam was better than starvation.

    alex wrote on August 16th, 2011
  7. I know the primal community isn’t attached to red meat the way big tobacco is attached to cigarettes, despite the snark.

    It seems quite reasonable that cafo beef WOULD be bad for people. First, it tastes like sh&*. Second, cows are fed toxic crap, confined, their intestines full of genetically modified grains & antibiotics & growth hormones, creating a growth medium for superbugs.

    Then, all the fat & organs that aaccumulate the toxins are mixed w/nitrates for processed meat!

    I don’t find it hard to believe at all that eating those animals is unhealthy. Studies like this, however weak, spur my commitment to local, grassfed beef, pork, goat, bison, chicken, duck, etc. And wild caught sustainable fish.

    fitmom wrote on August 16th, 2011
  8. Great post as always Mark!! You saved my life buddy!!

    Considering that I cured my T2 by eating hardly any other meat except red meat these past 3.5 months I can clearly de-bunk anything that any idiot doctor can come up with.

    I’ve lost 35 lbs, dropped 10% body fat, and now have normal levels of fasting BG when just 3 months ago, my doctor wanted me on Lipitor for having total cholesterol of 212, hdl 48, LDL 130 and trigs of 78…oh yea, and wanted me on insulin too!! I said no thanks, I’ll figure it out, and I found Mark’s Daily Apple!!

    Day 1 my fasting BG was 190
    Yesterday it was 97

    Yea I owe it all to Primal/Paleo life and lots of red meat and Bacon!!

    Thanks Mark!! When I reach my goal weight, you’ll definitely be getting my story to share with everyone!!

    Tim wrote on August 16th, 2011
  9. Mainstream media pisses me off! Journalists that probably don’t even have their weight in check writing this kind of stuff!

    The media loves this hype. Today I saw an article in Portuguese newspaper stating that “Fatties May Be Healthier Than Thin People”. They dug up a Canadian study that said that obese people with no physical or psychological diseases were healthier than the non obese or overweight people. Basically they compared a minority of obese people with “super genes” to the general population of non overweight people.

    All the overweight people were commenting and were relieved that they could go on with their “healthy diets”. No matter if you have high blood pressure, high cholesterol, insulin resistance and obesity because everybody was cheering! I know everybody wants to be accepted and feel good… But letting yourself being convinced by this utter nonsense is a big sign of stupidity! I didn’t bother commenting because the character limit of that comment was 150 characters… That is why I am venting here!

    Pieter wrote on August 16th, 2011
  10. people are destoried due to lack of knowledge, seek the truth and the truth shall set you free. question all wisdom!

    Dasbutch wrote on August 16th, 2011
  11. Thanks, Mark.

    Hugo wrote on August 16th, 2011
  12. I love these dissection of studies posts!! Totally awesome and keep it up, please!!

    Dawn wrote on August 16th, 2011
  13. Thanks. I am off to eat my gf lamb stew a 2nd night in a row.

    Sarena wrote on August 16th, 2011
  14. I’ve said it before….you can go nuts reading all the health “studies” out there.

    Mary Hone wrote on August 16th, 2011
  15. The way that I see it I am healthier eating primal! If I feel better I am going to continue my diet. If a diet really works there is going to be lots of studies that are bullshit.

    Josh San Diego wrote on August 16th, 2011
  16. Screw CW and everything related to it. Try different things out (what you do and don’t eat, how you move around, exercise, etc.) and if it works, great. If it doesn’t, then try something else. Some folks seem to do better on more carbs and less protein– not everything works for everybody. So, even if stuff doesn’t work for us, that doesn’t mean it won’t work for somebody else. Listen, listen, listen to what your body is telling you, and that’s the route you need to take.

    If you look good – and better yet FEEL good! – then just maybe it might be GOOD for you! Duh—

    All I know is that PB is really working for me.

    PrimalGrandma wrote on August 16th, 2011
  17. What really got me disillusioned a while back was the magazine ‘Men’s Health’. I was a very regular reader, but then I noticed that they would often publish articles, or short summaries of studies like the one you linked to. Often the same issue would have one piece telling us bacon was good for us, and another telling us it was death on a plate.

    I stopped getting the magazine, but then was really kind of stuck for what to do for a couple of years. Then a couple of months ago I found MDA, and have been going great ever since.

    I’m posting this from the stand up workstation I made yesterday :)

    phreeB wrote on August 16th, 2011
  18. Well, I’m a goner.

    I was outside in the sun all day (like I am everyday) standing and working with my hands… When I came home, I push mowed the lawn for the 45 minutes it takes, then did a bunch of other house chores that required all sorts of movement and stairs… and this was all with the anticipation for the 2 cups of creamed leafy greens and the big fat juicy blood red strip steak I had for dinner.

    If only I would have sat my butt down as soon as I got home and read this I could have avoided this certain demise I’m sure to face. I think I’ll sit as still as I can now and hope that no movement will minimize the damage that I undoubtedly will succumb to.

    Todd wrote on August 16th, 2011
    • Good grief – whatever you do, don’t even think about moving a muscle! ROFL!!

      (IMHO, you get a heads up for “sarcasm of the day”!)

      PrimalGrandma wrote on August 16th, 2011
  19. So if more people stop eating meat, does that mean that prices will drop and make my budget happier?

    David wrote on August 16th, 2011
    • The secret is buy bulk…..sshhh don’t tell anyone :-)
      we get hamburger for about $4/pound, we get 20 pounds at a time.

      bbuddha wrote on August 16th, 2011
      • I just picked up my 1/2 angus cow last Friday…steaks, roasts, ground, pot roast….and it wound up being about $5 a pound overall for grass-fed, pastured beef. SO excited. They even saved me the MASSIVE liver and heart, which I cut into pieces and froze in baggies to add into my dogs’ primal meals (and they are thriving too, by the way, 11 weeks primal for them too!)

        Peter wrote on August 16th, 2011
  20. Beautiful.

    Nick wrote on August 16th, 2011
  21. As a FORMER Insulin using type II Diabetic i can say that the ONLY thing that saved me from death and a life filled with medications was a paleo diet. I eat red meat, unprocessed and grass fed when I can get it. I eat pork, fish chicken, hard chesses and green and colorful veggies with a few berries and raw nuts.

    I do NOT have to use insulin or meds anymore. High healthy fat and limited protein has saved my life and changed my way of eating forever, Screw theses studies, they are full of crap!

    Dusty wrote on August 16th, 2011
  22. Thank you so much for writing about this study!

    When I read that news headline my heart sank. Diabetes runs in the family and I want to do everything to avoid it. I’ve been transitioning to a primal lifestyle and doing a ton of reading and it can be overwhelming sometimes.

    Thank you for writing about this study and breaking it down so that I can understand exactly why I have nothing to worry about!!!

    Bananya wrote on August 16th, 2011
  23. mark, hank you for the great post that spawned so many amusing comments. i love this site almost as much for it’s readers/commenters as i do for the great info that it provides!

    markbouvier wrote on August 16th, 2011
  24. I skipped straight to the proposed mechanisms where I found some very poor explanations.

    Iron is easily oxidised (think rust) regardless of the form it comes in. The heme structure as part of hemoglobin is used to safely oxidise iron and return it to an unoxidised state. Heme iron is found in all meat, not just red meat. There’s also much more iron in legumes anyway.

    On oxidation, the best antioxidants are glutathione and alpha-lipoic acid. Found where? Grass-fed meat.

    They bring up saturated fat without any discussion on how it may be relevant.

    Then in the ultimate discussion of mechanisms they say that red meat is associated with weight gain, which is associated with diabetes.

    Steven wrote on August 16th, 2011
  25. Yeah…The Statist Terrorists want to keep you weak and stupid in your tax farms by detroying you with their public schools, TV programming, eating high-carb/low-fat, and staying out of the sunlight. Doing these things make people vote for the political terrorists who want to own and control them. People (Especially American) have never been more stupid and weak since they started obeying the political terrorist over the last 50 years.

    IM Pericles wrote on August 16th, 2011
  26. When it comes to processed meats, there’s a huge variance in quality and health effects.

    Afterall, you get processed meats loaded with MSG, Dextrose, Maltodextrin, etc.

    Than you have processed meats preserved with nitrates and sodium.

    The differences between the two types of processed meats are stark, and somewhat overblown. After all, bacon cured with nothing more than salt is considered “processed meat” the same as a Johnsonville Brautworst, loaded with MSG, dextrose, corn syrup, maltodextrin, etc.

    But event then…in the worst case scenario….I believe even the worst processed meats are nowhere near as bad for you — especially in terms of diabetes — as so called health food like canola oil-saturated granola and whole wheat bread and whole wheat pasta.

    What these kind of studies really tell us is this: people who listen to conventional wisdom and try to eat healthy, versus people who don’t give a shit and eat anything and everything; including all the neolithic agents of disease (grains, sugars and Omega 6 rich, oxidized vegetable/grain oils) AND red meats and processed meats.

    Keoni Galt wrote on August 16th, 2011
  27. The are lies, damn lies, and then there are statistics

    David wrote on August 17th, 2011
  28. I have noticed people who walk frequently end up in a trauma center. So is walking dangerous or stepping in front of a moving car dangerous? Without mentioning the latter your conclusion may be that walking is dangerous?

    Greg wrote on August 17th, 2011
  29. Pretty much agree with everyone, these studies are stupid-frustrating. Buuut at least we in this community can make the distinction. Gonna go eat my semi (mostly) raw, grass-fed steak for lunch. STOKED

    dani wrote on August 17th, 2011
  30. I got an “observational” study for all of you. Both of my parents were diabetics. I stopped eating meat when I was 12 however I continued to eat all the junk food out there. I am now almost 50 and still NO signs of diabetes. hhhmmmm….maybe it IS the meat? My parents LOVED meat. They both also had heart disease. You meat eaters will argue anything to defend your right to continue to cause suffering, pollution and death…it’s funny actually…

    boochips wrote on August 17th, 2011
    • Sorry to hear your parents had heart disease.

      Meat notwithstanding, did they live healthy lifestyles? Exercise? Avoid processed/refined foods? Avoid transfats and fried foods? Are you sure it’s the meat that caused their heart disease and diabetes?

      Peter wrote on August 17th, 2011
  31. When you have a line like that which just stands out from the rest of a reasonable article, I wonder if that’s not something put in to satisfy the reviewers.

    And these authors are just trying to get a line on their CV so they can get tenure and keep their jobs most likely. They can’t afford to care about things like critical thinking and proper science.

    Such would kill their career.

    Michael wrote on August 17th, 2011
  32. Excellent post, I did a similar post on my blog, you’re went into much more detail.

    Problem is red meat consumption will always be correlated with a host of diseases because people were told back in the 80s the red meat is bad for you.

    So health conscious people started avoiding it – leading to the correlation between people who junk and red meat consumption.

    Amit wrote on August 17th, 2011

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