Review of Sacred Cow: The Case for (Better) Meat

The full title is Sacred Cow: The Case for (Better) Meat: Why Well-Raised Meat Is Good for You and Good for the Planet by Diana Rodgers and Rob Wolf. The book looks into the ethical and religious, environmental, and nutritional aspects of eating meat, as well as not eating ultra-processed junk. They argue, convincingly, that we are being sold an oversimplified narrative that the only approach to improve our health, cause the least harm to all beings (human and animal), and save the planet, is to eat a vegan diet. If you can’t go that far, at least eat as little meat as possible, especially red meat. The truth is, to put it mildly, more nuanced than that. They obviously did a lot of work researching this, and their writing is enjoyable. I recommend the book highly, regardless of what your current views are on this. Remember, they are paleo diet advocates, and I lean more towards whole-foods plant-based. But I pretty much agree with everything in the book on ethical/religious and environmental issues. I have disagreements with them about nutrition, which we’ll get to below. But that’s kind of the point. If we find common ground on the ethical/religious and environmental issues, only then is it possible to have a rational discussion about nutrition.

I’ve touched upon this in the past, and the main point was that the ethical/religious and environmental arguments make the discussion much more contentious, so opposing groups will not listen to each other and look for common ground or compromise. I mentioned back then that we could defuse this by using the term “reduceitarian” (as in the book of the same name by Brian Kateman) instead of “vegan”, and that everyone could do their part to address the “less harm” and environmental issues by not eating junk, and reducing their consumption of animal products. I also pointed that the paleo diet is already reduceitarian by limiting dairy.

I think Diana and Rob might agree that’s a step in the right direction, except they don’t think the focus should be on meat consumption, but instead on replacing modern industrial agriculture, both plant and animal, with a more sustainable version. They made powerful arguments on that point. I was especially fascinated learning about the environmental aspects, To me, feeding the world as nutritiously as possible, while doing the least harm, is an optimization problem. That’s in my “wheelhouse” because I used to write software for mechanical engineers to optimize their designs.

Up till now, I had read widely, and with an open mind, on the nutritional aspects of various diets (like whole-food plant-based, the paleo diet, and low-carb). But I hadn’t investigated the ethical and environmental aspects deeply enough. I had bought claims like the standard statistic, “meat production causes more greenhouse gas emissions than transportation”. I think in the back of my mind I wondered if it was exaggerated, but I never dug deeper. That’s why this book was such an eye-opener.

Giant fields of commodity crops like soybeans, wheat, potatoes, and corn are unsustainably farmed just to make junk food. That does a lot of harm, to bees and animals in the fields being sprayed, as well as to the environment. So who is doing the least harm, a “junk food” vegan, simply because they abstained from meat, or someone who avoids junk and gets their plant food and meat from from sustainable and humane sources?

Of course these are not the only two choices. There are plenty of vegans who also don’t eat junk food and sustainably source their food. But I’m afraid the message is slipping into the mainstream consciousness that you can save the planet by eating your crappy diet as long as you substitute an Impossible Whopper for your meat Whopper to go with your fries and soda.

And what’s often left out of the picture is that a lot of environmental harm is done from unsustainable farming practices of some plant crops. Rice is a major contributor to greenhouse emissions. The authors give evidence that “riceless Fridays” might actually be more beneficial than “meatless Mondays”.

The authors describe some examples of extremist, and rude, actions by vegans, which I was sorry to hear about. All the vegans I know personally are nice and gentle people who do not judge others for their food choices. To be fair, I need to point out that vegetarians and vegans often face questioning and sometimes contempt for their choices. I know I did when I was a vegetarian back in my youth, even though I was never trying to proselytize or “convert” anybody. This is yet more evidence of the “religious-war”-like nature of this issue, which I’d like to see taken down a few notches by both sides.

Bottom line: These are examples of how the issue is more nuanced than”meat bad, plants good”. What I totally agree upon is that if we want to do the least harm to our fellow creatures and the environment, the focus needs to be shifted to sustainable agriculture of both plants and animals. It is “factory farming”, or modern industrial agriculture, that is the main problem. The authors take it further and teach us about “regenerative” farming which actually improves the ecosystem, and show that humane integration of animals into a combined farming system helps make it regenerative. A great way to learn more about this is on the website “a greener world“, which has certifications like “animal welfare approved” and “regenerative” approved”. I would love to see that take off, much like free range certification for eggs or fair trade certification for coffee and chocolate. Diana is on the board of their animal welfare approved branch.

You can get more of the details by reading the book, or read on and I’ll give you my take. I’m going to discuss the issues in this order: ethical/religious, then environmental, then nutrition. This is actually the reverse of the order in the book. But as I said, only after the first two issues are addressed can we talk about the health effects of animal products rationally, and carefully listen to each others views.


I (and the authors) respect the views of those who avoid meat and other animal products for religious regions or humane reasons. For example Buddhists want to reduce the suffering for all beings. Or people may have seen documentaries showing cruelty to animals in the farming industry. This leads many to become vegan or at least reduce their meat consumption. There is a lot of cruelty in modern industrial animal agriculture. That is why I’ve support the Humane Farming Association (and will now add Diana’s Animal Welfare Approved to my list): A lot of this can be minimized by better farming practices.

The authors show that modern industrial farming of plants also causes a lot of suffering, and give a good argument that a sustainable farming combination of plants and animals can actually lead to less overall suffering, especially if you include the welfare of wild animals. For example, current practice is to grow giant “monocrops” like soybeans or corn. Just plowing the field kills animals, The heavy use of pesticides and herbicides like roundup is killing off bees needed for pollinating.

My wife and I are enthusiastic fans of a show on RFDTV called “FarmHer”. It chronicles the contributions of women in the farming community across the US, including farms with animals. From the many first hand accounts, it is clear that many women and men in the farming community believe passionately in sustainable farming and care deeply about the welfare of their animals. So does Diana, as is clear from stories from her farm in the book.

But couldn’t you take the further step of better faming practices and abstaining from meat to do even less harm? It depends on what you’re substituting for your meat, tofu from sustainably raised soybeans may be a good step, tofu from soybeans conventionally farmed may not be, because it may be avoiding harm to farmed animals, but causing harm to wild animals. An Impossible burger, made from a variety of conventionally farmed ingredients, is even less likely to be a step in the right direction.


Let’s start with one of the biggest misconceptions that’s become something “everybody knows”: animal agriculture, especially beef production, causes more greenhouse emissions than the entire transportation sector. It turns out the calculations on which this statistic is based are inaccurate. The authors meticulously chased the numbers for the claim about greenhouse emissions from beef production. For the details I’ll leave you to read the book because it is complicated to explain. But here is one tidbit illustrating the bottom line: the Epa estimates the contribution of all livestock in the US is 4% (only half that from beef), vs. 28% for transportation. Transportation actually contributes 7 times the amount of livestock! Compare that to the exaggeration being bandied about that agricultural livestock contribute more than transportation.

Pronghorn antelopes, fantastic endurance athletes. They can run for an hour as fast as a human can sprint.

Here’s another fascinating point that is overlooked in this discussion. You might be thinking, “wait a minute, what about all the methane from those cow farts?” First of all, ruminants, like cows, apparently belch methane, not fart it. But we currently have 94 million cows in the US. In 1850, there were well over a hundred million total ruminants on the great plains, and sadly a great many are gone now. These included bison, elk, caribou, deer, and pronghorn antelopes. Their methane emissions added up to about 82% of the current methane emissions from cows. But the world’s methane emissions have gone up by about 2 and a half times (250%) since 1850. I don’t think we can blame that on the cows.

Returning to the optimization problem, of providing the most nutritious food while doing the least harm to the planet, I’d always thought some animals fit in the mix. A lot of the traditional healthy “Blue Zones” communities herd goats or sheep on marginal land not suited for growing crops. There are a lot of cows grazing on our hillsides in California. I never thought they were the issue, it was the feedlots where you see (and smell) the cows crammed together when you’re driving south on Interstate 5. I first heard the marginal land argument, specifically using the example of sheep herding in New Zealand, from Dr. Grant Schofield and his colleagues in the book What the Fat?.

But the authors go further than this. They show the role animals, especially cattle, play in regenerative practices, which actually restore the soil and improve the local ecosystem. They contrast this with conventional practices that they refer to as extractive (I’ve also heard them called mining the soil). A lot more plants and animals exist in the healthy ecosystem of a regenerative farm, vs a conventional one:

The authors powerfully argue that regenerative farming that raises animals and plants sustainably causes less environmental harm than industrial agriculture farming of plants. Practices include rotating fields with plant crops and animals. The fallow field (with last year’s remaining harvest, or planted with a cover crop, is grazed on by the animals, who of course provide free fertilizer. The details are fascinating and encouraging. Another way animals can contribute is by fertilizing hillsides they graze on which otherwise can get depleted by runoff. I can attest to this mechanism, since I hike in open spaces where cattle grazing is permitted. There’s plenty of cow fertilizer. It’s a very good incentive to be mindful when you walk!

Definitely sustainable combined plant/animal farming is superior to conventional farming. What about sustainable plant farming? That’s superior to conventional also, but the authors make a case that the presence of the animals actually improves the situation, as long as the grazing is maintained properly. Their hooves improve the soil by working organic matter into it and improving its ability to hold carbon, which offsets greenhouse gases from the animals.

Here’s one crucial calculation: Can we produce enough food if we switch from grain-fed beef to grass-fed? They proved the answer is yes. And if we really want to make sure there’ll be enough land to make plant and animal food, a major step nobody talks about is to stop wasting the large percentage of cropland used for commodity crops to make junk foods. Grow something useful on it.

There is one other important misconception that needs to be addressed. That is the claim that it takes a lot more land to provide the same nutrition if its by raising beef rather than a plant crop. The authors investigate the claim and show the calculations are misleading. The thinking goes like this: “what if you grow corn, and eat it, vs. growing the corn, feeding it to a cow, and instead eat the meat from the cow”. This makes it seem like you’d need a lot less land if you just ate the corn. But even with conventional farming, only a fraction of the food that a cow raised for beef eats in its lifetime comes from food directly grown for it (feed crops). It spends the majority of its life on pastureland, then the last few months in a feedlot. Even in the feedlot a good percentage of the “grain” it’s fed is not from feed crops like corn but from agricultural waste. Second, you have to compare the nutrients from the beef vs. the corn. To match the protein and micronutrients, you’d have to supplement the corn with other plant foods.

This calculation is important to me because I’ve had that misconception in my mind for over 50 years! When I was 18 I read the book Diet For a Small Planet by Frances Moore Lappe. She showed how we can get high quality protein (the right blend of essential amino acids) by combining different plant foods, and that this has been done for centuries in traditional cultures (rice and tofu, tortillas and beans, etc.). This major contribution of her book has stood the test of time. But the title of the book comes from calculating how many acres it takes to grow the same amount of protein from animal protein vs. plants such as soybeans. For beef she estimated it would take over 10 times as much. But this calculations suffers the same inaccuracies as shown in the previous paragraph.



  1. Overall, I consider the overlaps between the authors’ recommendations and those I believe to be healthy are vital, These include eating no junk, minimizing dairy, and eating lots of healthy plant foods, The main point of contention is over how much meat should be in a healthy diet. I readily concede it doesn’t need to be zero, and may be number as high as 15%. The authors argue for a higher figure of 40%, and I’ll discuss the controversial evidence below.
  2. They make a very good point that nutrition needs vary at different stages of life, children vs adults, vs. aging adults. I totally agree and feel there is an especially important distinction between those in a growth stage vs aging (I am becoming experienced at the latter…)
  3. The authors concede you can be healthy on a vegan diet but only if you know what you are doing, You have to supplement missing or harder to get nutrients like B12 and omega3. And you can get enough protein but need to be careful to do so. I discussed protein combining above. Some vegan authors say you’ll get plenty of protein as long as you eat a variety of healthy foods. It depends on what you mean by plenty, as we’ll see below. I personally feel you need to at least audit your diet once in a while to assure adequate protein, and consider using concentrated sources like tofu or tempeh.
  4. The authors also argue that the evidence for the health consequences of meat eating are not as solid as presented in guidelines. This is a crucial point. If you concede, as I do, that some meat can belong to a healthy diet, the question becomes how much. Making an analogy with drugs, we want the optimal dose but minimal side effects. So it’s important if the evidence for “side effects” is solid or exaggerated. I still believe there are compelling concerns remaining about health aspects of excess meat consumption. I must agree to disagree on what amount constitutes excess.
  5. They specifically cover protein, and argue that the guidelines may be adequate to avoid deficiencies, but not to thrive. I agree with that. The current guidelines are for about 10% calories from protein. I’ve discussed previously why that is too low, and came up with an estimate of about 12%. The authors argue for 20%, which is still way below estimates I’ve found for the safe upper limit of protein. I’m not going to squabble about 12 vs 20. My only comment is that they assume the entire 20% has to come from meat. Why not some from meat and some from healthy plant sources (mushrooms, lentils, etc.)? This is important because there are health and longevity concerns over excess animal proteins in the diet (details below).


Let me review some background on where I come from on nutrition before I delve into how it largely overlaps, but somewhat contrasts, with the authors. I’m mostly a WFPB guy. The authors are more paleo (but having read Robb’s book Wired to Eat. he is more flexible in his interpretation of paleo, as I am of WFPB). The term “whole food plant based” (WFPB) was coined to distinguish from an unhealthy vegan diet. WFPB is, in a nutshell: no junk, a variety of healthy minimally processed plant foods, minimal dairy, and reduced meat (including fish). A healthy vegan diet is a subset of WFPB that has no animal foods. Unfortunately, “whole food plant based is quite a mouthful”. So the shorter “plant based” is now in vogue. But french fries and oreos are plant based! Leaving out the “whole foods” takes us full circle back to “junk food vegan”.

Now let me contrast WFPB with the Paleo diet, which I discussed previously here. Paleo is an attempt to follow a diet closer to what we evolved on, specifically before the onset of agriculture. It can be summarized as no junk, a variety of healthy minimally processed plant foods, minimal dairy, minimal grains. Previously this diet discouraged legumes also, but now they’re considered OK unless you’re intolerant.

Note that there is considerable overlap between the two diets. The contrast is mostly between limiting meat in WFPB, vs. grains in Paleo. And as to grains, grain intolerant people can certainly follow WFPB and use gluten-free grains or pseudo-grains instead like buckwheat or quinoa (which are both really seeds).

Meat is the more crucial contrast between the two diets, especially in connection with discussing this book. WFPB recommends considerably lower amounts than paleo.

Ok, on to the details. I readily agree with the authors on all points above except 4 and 5. I refer you to the book for details of the discussion of points 2 and 3. So let’s go over 4 and 5.

First I agree with the authors in their discussion of the quality of evidence from nutritional studies. Animal studies provide important clues, but not proof. And “Correlation is not causation”: the authors give an amusing example of this. I’ll add my own. Coffee correlates with lung cancer. Does it cause it? Of course not. It turns out heavy smokers tend to be heavy coffee drinkers as well. However, epidemiologists are experts on using statistical methods to correct for effects like the coffee/smoking confusion. Another important point is that animal studies are not enough to prove the same issue occurs in humans. Both observational studies, like the famous Framingham heart study, as well as animal studies, can raise concerns. Interventional studies in humans are needed to provide proof. But when multiple studies point to similar concerns, that is enough to raise a red flag for me, personally, even if they technically don’t yet constitute proof.

Health aspects (“side effects”) of meat

A lot of the discussion of meat hinges on whether saturated fats are healthy. I’ll concede the authors point that the science on this is not as settled as commonly thought. Here’s my take. A major conventional argument goes like this: the ldl (bad cholesterol) number below which Heart attacks are rare in traditional populations, including hunter-gatherers, with and ldl (bad cholesterol) of 70 or less. Ldl is well-known to go up when you add more saturated fat to your diet. End of story. Well, not quire…

The latest word is that what really matters is oxidized ldl. The likelihood of having oxidize ldl is reduced if you have a high ratio of good cholesterol (hdl) to triglycerides, in which case TC or even the amount of ldl may not matter. As an aside, note that the second author of the “ldl under 70” study is paleo diet proponent Dr. Loren Cordain, who believes it’s important for any meat consumed to be lean because that better approximates the wild game consumed by hunter-gatherers. One last aspect to consider is that interventional studies have conclusively shown that a diet that leads to the very low ldl mentioned above reverses coronary artery disease (CAD) [1,2]. I’m not aware of any studies showing the second approach, of keeping hdl high and triglycerides low, reverses CAD or even prevents it (although minimizing oxidized ldl is certainly a good sign). Since I already have signs of CAD, I still minimize saturated fats in my diet.

I lot of authors and some nutritionists seem to believe that saturated fats are the main issue, but there are other health aspects.

The authors argue that the recommendations to reduce red meat (especially processed versions) because it is carcinogenic are not as solid as we think. These are based on WHO guidelines for hazardous substances, which say red meat is carcinogenic, but not how strongly.

There does seem to be a negative association between protein intake from animal sources and all-cause mortality, ref [3] is one example, but there are multiple references like this, But remember correlation vs. causation, above, so more evidence is needed for proof, although this does raise concern.

Other aspects include a variety of harmful substances like TMAO, which I discussed previously. The authors give some references that question how strong the claim is that these are harmful. I chased these and contrasted them to my previous references, and frankly do not have the nutritional biochemistry background to tell who is right. So I’ll just leave it that this point is controversial. However, I’ll point out the Dr. Michael Greger, who review thousands of nutritional studies every year, and does have the appropriate expertise, remains firmly convinced that there are many unhealthy “side effects” of meat (see details on his website and in his book How Not To Die)

But there remains a vital point that was not discussed in the book. I mentioned the role of nutrition in different stages of life above. The are substances which are healthy and beneficial for a growing organism, but actually can become harmful (e.g. cancer-promoting) in excess for an aging organism. These include IGF-1 (“insulin-like growth factor 1”) and mTOR (“mammalian target of Rapamycin”). There is a really good discussion of this in Dr. Valter Longo’s book The Longevity Diet. It’s a fascinating story and it has to do with the long history of researching diet and longevity, including caloric restriction. It turns out the beneficial part of caloric restriction for longevity has been traced to restriction of animal proteins. The evidence in humans is more correlational [3], except we do have the evidence that all of the longer-lived Blue Zone populations eat significantly lower amounts of animal protein than the general population.

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What’s the Safe Upper Limit For Meat in a Healthy Diet?

This is point 5 above. Right away, based on some of the Blue Zones populations, I’d concede the safe upper limit could be at much as 15%, The authors argue for more like 40%, so we have a bit of controversy here. One issue I have is that they accept Dr. Cordain’s controversial number of 45%-65% of calories from animal foods being in the diet we evolved on. But since we’re looking for a safe upper limit, I’ll concede that at least some of the population may thrive on a higher level. Our tolerances vary, as shown in Wired To Eat. There are known genetic variations, for example, in the gene that determines how much salivary amylase we have in our saliva. Those with less tolerate less starch but possibly more meat.

The other way the authors approach it is looking for the right amount of protein, and as we saw above they came up with 20%. Since lean beef, for example, is about 50% protein, that leads to about 40% meat. Normal recommendations for protein are about 10%, I’ve discussed how children, athletes, and older adults might need more like 12%. The authors correctly point out the protein has a high satiety value so more of it might help prevent overeating. But they assume all of our protein intake has to be from meat. That is the main bone of contention (no pun intended). Especially for aging adults, there is the issue of the relation between animal protein and longevity discussed above. This concern could be addressed by getting at least some of your protein from plant sources.

I would add an argument in favor of higher total protein (plant plus animal) for aging adults however, and that is prevention of muscle loss (sarcopenia). In his book, Dr. Longo describes the centenarians he knew in the region of Italy he grew up in (sounds like another Blue Zone). They are healthy, but somewhat frail. He thinks adding some fish to their diet would help with this. The centenarians in China described in the book Longevity Village are healthy and robust. And they have a significant amount of fish in their diet. The point is not fish specifically, but adequate high quality protein. But even this argument points more towards the figure of about 12% protein in the diet, not the 20% assumed by the authors.

On Longevity

One of the problems with looking for traditional populations with good longevity is they don’t often have access to good health care, and may have a higher incidence of child mortality. The average longevity of the population seems lower, but if you compared those who reach adulthood and don’t die of infectious disease, they be healthier and longer-lived than modern populations. That argument is made here. But there are ways to correct for that, for example looking at the life expectancy of members of a population make it to middle age (e.g. to menopause for women). For example, the Tsimane in Bolivia are ahealthy traditional population that are a combination of subsistence farmers and hunter gatherers, They have very low incidence of our number one killer, heart disease. The “middle-age corrected” longevity of Tsimane is about 70 [4]. The last remaining hunter-gatherer people in the world I am aware of are the Hadza of Tanzania. They appear to eat a diet of about 70% plant, 30% meat. Their corrected life expectancy is also about 70 [5]. This is somewhat lower than the typical longevity in populations eating a modern diet. Contrast this to the Blue Zone populations who get a lot of their protein from plant and less from animal sources, whose longevity is higher than populations on a modern diet, and have higher rates of people living to 90 or 100. Given that I’m 68, the idea of making it to 90 or 100 is more appealing than 70!


My overall take away is: don’t eat junk, and support organizations that promote regenerative agriculture, and try to buy your food from sustainable sources (local doesn’t hurt either). That’s the best approach to causing the least harm. Not eating junk is the most important step, health-wise, as long as you make that, you’ll be far healthier than those eating the typical modern diet. And please don’t judge people whose food choices differ from yours. As for the controversy over the amount of meat that is healthy, I’ll leave that up to you to decide. For me, the longevity issue still seals the deal, so I think replacing a good percentage (not necessarily all), of your animal protein with healthy plant sources is a good step to consider..


  1. Ornish, D, “Can lifestyle changes reverse coronary heart disease?: The Lifestyle Heart Trial”, The Lancet,, 1990.
  2. Esselstyn C, “A way to reverse CAD?”, J Fam Pract., 2014.
  3. Song, M, et al, “Association of Animal and Plant Protein Intake With All-Cause and Cause-Specific Mortality,” JAMA Internal Medicine, 2016
  4. Gurven, M, et al, “Mortality Experience Of Tsimane Amerindians Of Bolivia“, American Journal of Human Biology, 2007.
  5. Pontzer, H, et al, “Hunter‐gatherers as models in public health“, Obesity Reviews, 2018.

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