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Grass-Fed vs. Conventional Meat: It’s Not Black or White


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This article is part of a special report on Red Meat. To see the other articles in this series, click here.

I hope you all had happy holidays and are off to a great start this year. I thought I’d share a few thoughts that have been bouncing around my head lately, stimulated most recently by two articles written by fellow health bloggers.

Don Matesz over at Primal Wisdom wrote a thought-provoking piece on the hormone composition of grass-fed and factory-farmed meat. In it he argues (convincingly, I might add) that meat from CAFO (confined animal feeding operations) does not have dangerously high levels of hormones, in spite of claims to the contrary made by advocates of eating grass-fed meat.

Got testicles?

I recommend reading the entire article, I’ll summarize it briefly here. Before CAFO came into being, humans predominantly ate bulls, since eating female animals (cows) was taboo. The taboo made perfect sense in a hunter-gatherer culture, since killing the female could eliminate potential offspring, while killing a few bulls would have no effect on the fecundity of the herd.

Today, CAFO use steer, which are neutered bulls. One reason for this is that steer are a lot easier to manage than bulls. Why? Because hormone levels in bulls (with intact sex organs) are significantly higher than in steer. In fact, bull meat has between 34 and 105 times more testosterone than steer meat. No wonder bulls are harder to manage!

Even when hormones are added to steer in CAFO, the levels are nowhere close to what they are in intact bulls. In fact, studies have found no significant difference in hormone levels between meat from hormone-treated and untreated animals.

This means that Paleo Pete was eating meat with a lot more hormones in it a million years ago than American Andy is when he gets a cheeseburger at McDonalds today.

Hormones in meat are bad – if you eat 200 pounds of meat a day

Studies have also shown that the hormones ingested from food, including CAFO meat, have a negligible effect on human health. From Don’s article:

For example, a prepubertal boy, most vulnerable to adverse effects of excess dietary estrogens, produces about 100 micrograms of estrogen daily. Beef muscle meat contains less than 0.02 micrograms of estrogens per kilogram. To get from beef an intake of estrogens equal to just one percent of his endogenous estrogen production, i.e. 1 microgram, he would have to consume 50 kilograms–110 pounds– of beef in a day!

Another common claim is that adding hormones to meat has increased the rates of cancer and other modern, degenerative diseases. But if that were true, we would have seen these diseases in hunter-gatherer populations that were eating large amounts of bull meat, which has on average 50 times more hormones than the CAFO steer meat eaten today.

So it would seem that there isn’t much difference between grass-fed and CAFO meat when it comes to hormones. So should we all just save some money and eat conventional meat?

It’s not all about hormones. Don’t forget omega-3s!

Not so fast. Mark Sisson published an article earlier this week reporting on a study comparing the effects of eating grass-fed and CAFO meat on omega-3 and omega-6 concentration in human plasma and platelets.

Turns out those that ate the grass-fed meat had significantly higher levels of omega-3 in their plasma and platelets than those that ate CAFO meat, despite the fact that the amount of omega-3 fatty acids in the two types of meat were not hugely different.

The folks consuming grass-finished meat ate, on average, 65 mg/d of long chain omega-3s, while those eating concentrate-finished meat ate about 44 mg/d of long chain omega-6s, yet the lab results – the big improvements in plasma and platelet fatty acid numbers – were lopsided.

What’s happening here? I suspect the answer lies with the difference in omega-6 content in the diets of both groups. Those who ate the CAFO meat had an average intake of 8.5g/d of omega-6 fats, while those that ate grass-fed meat had an average intake of 5.5g/d. In a previous article about how too much omega-6 is making us sick, I explained that omega-6 and omega-3 fatty acids compete for the same conversion enzymes.

Several studies have shown that the biological availability and activity of n-6 fatty acids are inversely related to the concentration of of n-3 fatty acids in tissue. Studies have also shown that greater composition of EPA & DHA in membranes reduces the availability of AA for eicosanoid production.

This works the other way, too. The more omega-6 is consumed, the less omega-3 is available to the tissues. So if two people eat a diet identical in omega-3 content, but one person’s diet is high in omega-6, and the other persons is low, guess who will end up with more omega-3 in their tissues? That’s right – the one with a low omega-6 intake.

This is why I constantly tell people that the most important step they can take in normalizing their omega-3:omega-6 ratio is not boosting omega-3 intake, but reducing omega-6. And this is likely what explains the higher levels of omega-3 in the grass-fed meat eaters in the study, even though grass-fed meat doesn’t have a lot more omega-3 than CAFO meat.

This is important because the ratio of omega-3 to omega-6 in our tissue is crucial to health. Too much omega-6 in relation to omega-3 has been shown to be a factor in everything from depression and arthritis to heart disease and diabetes. There isn’t a modern disease out there that isn’t influenced by this ratio.

Black, white & shades of grey

So here we have one study suggesting there isn’t much difference between CAFO and grass-fed meat, and another suggesting the opposite. What do we make of this?

As much as we’d all like things to be simple when it comes to food and health, they often aren’t. We have to use our brains to sift through the available information and make intelligent choices based on several different factors.

In the case of grass-fed vs. CAFO meat, there’s a lot more to consider than hormones and fatty acids. There’s also antibiotic use in CAFO cattle and the increased risk of foodborne illness in CAFO meat, and there are several economic and social issues as well.

Grass-fed animals are generally treated in a more humane way than CAFO animals. If you’ve ever visited a CAFO you will know what I mean. It’s shocking and disgusting. I personally prefer to support local farmers that use traditional methods of animal husbandry, that pay attention to how the animals are treated and slaughtered, and who care about every phase of the process. I like the money I spend on food to stay in my local community whenever possible. And if you’re looking for a different alternative, there are several benefits of using bone broth when cooking as well!

Clearly, this is not a black and white issue, and there’s a lot to take into account when choosing between grass-fed and CAFO meat. As usual, I’d love to hear your thoughts.


Join the conversation

  1. grass fed beef wins simply because of the omega 3 benefit. if i eat more grass fed beer, free range chicken etc…. i am reducing my omega 6. It’s a no brainer.

  2. Thank you for your artical. I am a non-CAFO livestock farm and appreciate the free knowlege and desire to educate people on the difference in grass fed meat production. However in that same realm of knowledge there is a critical fact that is often overlooked. The Holstein cow picture often shown in these articals makes me cringe every time. The black and white Holstine cow is almost strictly a dairy animal they are not used in beef meat production.

    • Stress and worry is worse for health than anything. People who stress and worry over what they eat are undoing any good from it. And trust me if you listen to all the fear mongering out there and info about what you can’t eat or use or wear you will most likely be very stressed trying to figure out how you can have the time, money and energy to keep up with it all.

      • Incorrect, biased conclusion based upon small sample size. Worrying is an imprecise word, as is “stress”. As, actually, are “happy” and “sad”. All can be positive, the first two are not necessary in bad ways, and a personal inability to process data is a badly made point.

        Much like saying, “I get frustrated and fretful while trying to understand math. Perhaps my strategies are bad and ineffectual, and I almpst certainly might have mental incorrectnesses in approach, as most humans – nearly all to all – do, but studying math is pointless and inherently stressful and worrying in an unhealthy way. Much better to avoid it because it is too difficult and impossible, or at least study it lightly and semi-casually.

        This is a terrible, weak argument. Weakness and strife and difficulty are not inherent. If you are going to be dishonest with yourself, at least do not go spreading harmful, objectively incorrect ideas about as if they were acceptable and defensible.

        Also, consider the cost-benefit of fixing the causal (likely bad approach) to a better understanding and discement of health and diet in general.

        • No it’s not a weak argument. I have seen this phenomenon in many people. People who are very concerned with what they eat are stressing over it a lot. There are many people who can’t really afford to be doing all the the things that the fear mongers promote who try to anyway and all the stress created from their efforts to do things they can’t really afford in money, time, energy etc are probably hurting their health more than if they just ate Cafo meat. Heck just believing the lie that it is highly toxic and dripping with hormones and antibiotics probably causes harm. The placebo effect is very real.
          Don’t get me wrong I’m not saying it isn’t good to do what you can when you can and that you shouldn’t eat whole foods and stay away from the most egregious processed junk foods but people can become so obsessive that the harm from perfectionistic food requirements and the fear that drives the obsession can outweigh any good from efforts to eat perfectly.
          If you read Malcolm Gladwells book outliers you will learn about a group of Italians in a small town in the US that stumped researchers because they lived longer and had much lower disease rates than Americans. They thought it must be that they had stayed away from the sad diet. That turned out to be wrong. It was that they stayed in a tight knit community and had ver close loving social bonds which lowers stress levels and increases immunity.
          My point is that if focusing on food perfection becomes onerous burdensome and stressful then it won’t help your health much. And there are other things that have been proven to help health as much or more than not eating CAFO meat or avoiding anything that has ever touched plastic or is not organic etc.

  3. Chris: The competing nature of Omega 3 and Omega 6 fatty acids poses a question: If one eats foods higher in Omega 6 as a snack (like nuts & seeds) separately from the rest of one’s diet, does that eliminate some of that competition? For instance- eating a breakfast with Omega 3 eggs, few hours later a snack with Omega 6 nuts, few hours later grass fed beef with Omega 3, etc.? Thanks for all your great information and fair treatment of all ideas.

  4. Thanks for the link to your article on omega-6 fatty acids. My general opinion is that all of the little benefits of grass finished animals (a little more omega-3, a little less omega-6, no artificial hormones, no antibiotics, etc) lead to a much healthier product, for the consumer and the environment in general.

  5. Katherine, that’s a great point! We have several community farmer’s markets where we can buy grass-fed meat, and often times the farmer is there answering questions, with photos of his animals and the farm and an open invitation to visit. I like being able to look someone in the eye and talk to them about the meat they produce. However, sometimes the individual prices are very expensive, and we can’t afford it all the time. I spoke to the farmer, and they do half and whole cows for HALF the price per pound, and honestly it’s cheaper than the CAFO meat at the store down the street. Splitting it with like-minded families and we all win. I wish more local farmers could provide meat to stores at reasonable prices, but until people really understand that the money they spend on healthcare and junk food would fund their grass-fed and pasture raised tendencies, it will be difficult.

    On another note, one of the most disturbing things I learned about CAFO beef, is that the grain they eat is now treated with a pesticide so that once it is digested and excreted, their “excrement” will kill pests. They are ingesting pesticide that survives their digestive tract, and we’re supposed to believe that none of that is in the meat? Okay….

  6. For all of the very solid and convincing reasons laid out by Chris and submitted by the blog readers of this article, I try to buy, serve and eat grass-fed meat (and pasture-raised fowl). But here’s one more (I believe) good reason: The more consumers understand their options and get on board purchasing and consuming naturally-raised meat and fowl products, the more widely available and affordable those products will become. Then we ALL can be healthier. (Just take a look at how the natural and organic food industry has finally come of age. When I was desperately trying to raise my children on naturally raised whole food stuffs 30 years ago, the pickins were mighty slim and extraordinarily expensive…) Speak with your wallet.

  7. In the book “The Perfect Health Diet” I’ve read that both Paul and Shou Ching get their meat in the supermarket, because they eat at least 1 pound of wild salmon and sardines per week. Since I have learned about grass fed vs. CAFO meat, I only buy grass fed, despite eating 2 portions of wild salmon per week. I can’t bring myself to eat mass produced meat any longer. I’m wondering what your take is on this…

    • There are many other reasons (social, political, economic) to buy grass-fed meat above and beyond the nutritional advantages.

  8. Don: I know you’re not making that argument, and I hope I didn’t come across as suggesting you were in this article. If so, I’m happy to revise it. Just let me know.

    The question is, if someone can’t afford to get all their meat from grass-fed operations, will eating conventional meat pose all the risks commonly claimed, or is it more important to follow a species appropriate diet, and consider grass-fed meat a way to fine tune the generally correct approach of eating meat, fats, vegetables, and fruits.

    I think that’s a great question to raise and I’m glad you’re addressing it in your series. It’s important to be clear on what the advantages and disadvantages of CAFO vs. grass-fed are, because there’s a lot of misinformation on both sides. I’m looking forward to the rest of your series.

    • So we’re quite sure the fact that half of UK girls are entering puberty before age 10 is not due to meat or dairy, but rather carbs?

  9. Hi everyone,

    Great discussion. As I mentioned at the end of the article, there are indeed several other factors to consider when determining whether to buy CAFO or grass-fed meat. I am personally convinced that grass-fed is a better choice from every perspective – nutritional, social, economic and humane.

    At the same time, I think it’s important to have accurate information about the relative merits of grass-fed meat. This adds credibility to any argument we might make in favor of it (i.e. by not making claims that can’t be supported by the evidence). There are so many reasons to avoid CAFO meat, but the hormone content does not seem to be one of them.

    However, the hormone content in CAFO dairy products is a significant issue, from what I’ve seen. CAFO milk has higher levels of IGF-1, which can definitely cause problems.

    • I certainly have not argued that CAFO meat is equal to grass-fed. The question is, if someone can’t afford to get all their meat from grass-fed operations, will eating conventional meat pose all the risks commonly claimed, or is it more important to follow a species appropriate diet, and consider grass-fed meat a way to fine tune the generally correct approach of eating meat, fats, vegetables, and fruits. That is why I’m writing this series on conventional beef. I don’t want people to give up on a paleo diet because they think that they have to have grass-fed meat to make it work.

    • Dr. Kresser,

      I’m curious to find out the level of natural Estrogen found in meat, poultry and dairy. Is there such a list?

      My teacher in college told the class that eggs are pack-full of Estrogen can cause heavy bleeding in menstruation.

      She told the class that consumption of 2 eggs per day is way too much, due to the estrogen as well as cholesterol (precursor of estrogen hormone) level.

      I’m really curious to find out the validity of this statement!?

      Is there such list which show the natural Estrogen content in Egg?

      Thank you

  10. That’s a good point, Mar. In the early 20th century, Sir Albert Howard argued that the health of the soil is fundamental to the health of all things living on land. At the time, he didn’t have scientific proof, but he had a solid basis in tradition and common sense. Research into organic food production has borne him out, but I think it’s important to consider his approach. Science can confirm or refute what we already believe, but it’s useless for helping us to understand the full range of consequences for adopting new technologies.

    Isaac, you also have a good point. Could it be that hormone-fed beef actually has the opposite hormone balance of intact bulls? I thought castration was also used to increase the growth rate of animals, not just make them more docile. That happens with capons, doesn’t it? Correct me if I’m wrong, but it sounds like feeding hormones to steer is actually a form of chemical castration – one step further than the surgical kind.

  11. IMO, we can only be as healthy as our environment is. That’s my problem with paleo: our ancestors were healthier because the environment was healthier. Pretending to follow a paleo diet drinking water with fluoride and antidepressants as well as eating cafo meat and chipotle food for lunch is mind-boggling to me. If you are a healthy 20-year-old I suppose you can do whatever you want for a while while you are still strong. But how are you gonna age? I don’t need to wait for a scientific study to tell me that grass-fed meat is superior in all aspects to cafo meat. Choosing the road of cheap eating and disregard for the environment -as well as flawed science- is gonna do a great disservice to the paleo movement.

  12. There seems to be a push among the latest generation of WAPF leaders to re-popularize certain food groups even at the expense of the quality of such foods. I am not sure this is wise, nor healthy. Already studies done in Puerto Rico 3 decades ago on the effect of hormones in CAFO poultry had on the general population and it was conclusive that it advanced physiological sexual maturity in girls by a few years and caused boys to have breasts. Now this does not require science, a trip to Puerto Rico will suffice. Fully sexually-mature 11 year old girls are very common. By the way, chickens are fed estrogens, not testosterone.

    There is also the environmental toll of such food production to consider. CAFO operations are one of the prime consumers of GMO grains, which means somewhere out there there are vast extensions of land being sprayed to lifeless dust so that we can eat cheap meat. We all pay a high price in pollution, quality of air, water, land, etc from such food production. Never mind that they are huge energy suckers. They only reason they are profitable is the huge amount of subsidies they receive (which comes out of our collective pocket, so add that to the price tag on the supermarket). We can’t be healthier than the surrounding environment.

    I understand it is important people go back to real food. But real food, in the evolutionary sense, did not grow in CAFOs. But the WAPF health food movement should not abstract types of food from the quality of their production. Health is a very complex web of co-evolutionary relationships and eating respectfully grown foods is as important as eating such food types. After all, over the past century, the world’s health has been declining in direct proportion to the industrialization of food production, distribution, and storage.

    Instead of convincing people that cheap food is ok, something that came about with industrial agriculture after WW2, we should make them more aware of what they eat, they socio-economic ramifications it has, and how it affects their body.

    • Issac,

      If you read my article, you will find that research has failed to show that the increased incidence of premature or inappropriate sexual development in Puerto Rican children was due to hormones in poultry or any other meat product. People overlook the fact that high carbohydrate diets can cause premature sexual development by stimulating the endocrine system.

      I did not write the article to say that we should all forget grass-fed animal products and just use conventional. I studied the data to see if there is evidence for the health claims made against hormone use in conventional meat production, because not everyone can afford top quality grass-fed beef.

  13. Grass-fed meat should also contain much higher levels of some key vitamins and minerals. This is also a very important point to consider when choosing meat.

    It would be interesting to know if the fact that we don’t eat bull meat anymore is one of the reasons why men’s sperm count and infertility rates are so alarming today.

  14. You talk about hormones in beef as though all hormones were created equal. I’m not a doctor or a vet, but naturally occurring hormones may affect cattle very differently than artificially added hormones. Look at hormone replacement therapy given to menopausal women. Doesn’t it affect women in ways that their natural hormones do not?

    Those issues aside, just looking at pictures of a CAFO farm should encourage people not to support them, if only as a humanitarian issue for the sake of the livestock.

    • This is precisely what I was thinking! The adverse effects of the hormones is not be/c they are hormones but be/c the hormones are GMO’s. There have been studies showing mice fed GMO’s are sickly in the first generation, increasingly infertile in the second and third and by the fourth or fifth generation, completely sterile. These animals in the CAFO are being given genetically modified hormones, they are not naturally producing them.

  15. I share Bryan’s concern. I try to eat very fatty meat, and I also eat bone marrow and make stock with bones. I’ve heard that heavy metals and pesticides concentrate in both the fat and the bones. It’s very frustrating because I can’t even buy feet from grass-fed cows – the small-scale slaughterhouses that the farmers use don’t have the proper equipment to scald the feet for legal sale. So I make stock with grass-fed shanks, grass-fed knuckle bones, grass-fed tails, and CAFO feet.

    Of course grass-fed meat tends to be leaner, which for me is a serious negative. I occasionally buy grass-fed suet, but because I have to special order it, and CAFO fat is so cheap and easy to come by, I also get CAFO trimmings from my butcher. I try to use the rendered fat for disposable purposes like deep-frying rather than for browning things that are going to stay in the stew or absorb all the fat. For that I use the leftover fat from making stock, but it usually runs out.

  16. Chris,

    This is all interesting information. One additional point about CAFOs is that they typically use feed that is full of pesticides, herbicides, and GMOs. These chemicals and/or their break-down products may be in much higher concentrations in CAFO meat, especially in the fat, most of which is added during the CAFO feeding. I have not seen any studies addressing this issue, but it could potentially add to our toxic load and increase risk for cancer. Regardless of how much personal health risk is added by CAFO feeding, as you mentioned, environmental and humane issues associated with CAFOs are staggering and these issues alone are worth bypassing CAFO products as much as possible. After all, it is our dollars and choices that have built this system.

  17. Chris,

    I’m a new reader of your material, but find it very interesting. In the above article about grass-fed vs. CAFO meats you mention that high levels of omega-6s vs. omega-3s are are what you need to avoid. Can you expand on this? In other words what foods that are high in omega-6s should I (we) be avoiding? Thanks.