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

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, quite compellingly, 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 superb. I could not recommend the book more highly more 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 had some nits to pick 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 definitely sold me 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 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 that “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. So many become vegan or at least reduce their meat consumption. There is tremendous 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 more sustainable farming practices.

The authors show modern industrial farming of plants also causes a lot of suffering, and give a strong argument that sustainable animal farming (or sustained farming of a 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 stores 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 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 in 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 your 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:

They powerfully argue that regenerative farming that raises animals and plants sustainably causes less environmental harm than industrial agriculture plant farming. 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.

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 are 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 if you just ate the corn. But even with conventional farming, only a small 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 the 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 are healthy, such as eating no junk and lots of healthy plant foods, to be vital, The main point of contention is over how much meat should be in a healthy diet. I readily concede is not zero, it is a number as high as 15%. The authors argue for a somewhat higher figure, and I’ll discuss the 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 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. The authors give some sad examples of children raised by vegan parents who didn’t know enough about nutrition.
  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 is 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.
  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).

One thing has always amused me about the raging controversy between WFPB and Paleo. Lots of authors in both camps recommend 80/20 eating. Nobody’s perfect, so strive to follow the diet really strictly 80% of the time, and “let your hair down” 20%. So I could be really strict about limiting meat most of the time, but allow it 20% of the time. A paleo follower could be really strict about limiting grains most of the time, but allow them 20% of the time. We might end up eating almost exactly the same thing overall. We’d only disagree on when we thought we were being strict!

Meat is the more crucial contrast between the two diets, especially in connection with discussing this book. WFPB recommends 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 lung cancer. Does it cause it? Of course not. It turns out heavy smokers tend to be heavy coffee drinkers as well.

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 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 meat consumed to be lean because that better approximates the wild game consumed by hunter-gatherers. Ok, on to other health aspects.

There is a negative association between protein intake from animal sources and all-cause mortality [2], But remember correlation vs. causation, above. So more evidence is needed.

The authors show 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.

Other aspects include harmful substances like TMAO, which I discussed previously. They give 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.

But there remains a vital point that was not discussed. 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 he goes with the alphabet soup again. Sorry. 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 [1], except we do have the evidence that all of the longer-lived Blue Zone populations eat 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 the Blue Zones populations, I’d concede it’s at least 15%, The authors argue for more like 40%, so we have a bit of controversy here. Their discussion is very well reasoned and with good evidence. One issue I have is that they accept Dr. Cordain’s controversial number of 45%-65% 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 this higher level. Our tolerances vary, as shown in Eat To Live. 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% animal products. 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 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.

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.

The real issue is preventing the scourge of chronic diseases like heart disease, diabetes, and cancer that have been attributed to our poor modern diet. The next best thing to proving longevity is finding populations that are free of these diseases. In addition to the Blue Zones populations, these all tend to be subsistence farmers, like traditional people in Africa and rural China. They all ate a diet with no modern processed junk, also happen to eat a diet lower in meat, because subsistence farmers tend to be poorer and not able to afford as much meat as richer people or modern populations. There is at least one healthy Traditional population that are a combination of subsistence farmers and hunter gatherers, the Tsimane in Bolivia, but their diet also only gets 14% of its calories from animal products. Are there any healthy populations that eat a diet higher in meat?

The Masai come to mind for many people. They traditionally ate a diet high in meat and low in animal products, but absent of modern processed foods, and are cited as being free of heart disease, but the evidence is not conclusive. They do not have particularly high longevity, but that is why I put in the caveat above. They are certainly robust. If facing down lions with spears isn’t enough, David Rudisha proved to the world how robust they are, including at the Olympics in 2012. Here’s the evidence they are free from heart disease: A doctor visited them in 1972 and was permitted to perform autopsies on 50 deceased men. They showed signs of atherosclerosis and significant thickening of the coronary arteries “which equaled that of old U.S. men”. But there were “very few complicated lesions” and he speculated they may be “protected from their atherosclerosis by physical fitness which causes their coronary arteries to be capacious” [3]. As I’ve discussed previously, a heart attack is not caused by clogging with plaque like a pipe. It is more like a pimple bursting, then the clot forming. “No complicated lesions” might be a hint this was less likely, and having larger coronary arteries doesn’t hurt either. This is compelling, but not conclusive, evidence. The other population that is often claimed to be free of modern diseases on the traditional diet is the Inuit in the Arctic but that appears to be a myth [4].

There is an article here that discusses the longevity of hunter gatherers, but the only evidence it gives is the Tsimane, who as we saw do not eat a high meat diet.

I haven’t yet seen scientific proof of healthy populations, free of modern chronic disease, that eat a diet that gets more than 15% calories from meat. It may be out their and I’m not aware of it. Please tell me in the comment section if you’re aware of any.


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. And eat the amount of meat you think is the most healthy for you. 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.

I personally believe that at least for people in my age group (that is the cue for millennials to roll their eyes and say “OK, boomer”), replacing some of your animal protein with healthy plant sources might be a good option.

Finally, thanks Diana and Rob, for the tremendous work you did on this truly eye opening book.


  1. Hristov, A, “Historic, pre-European settlement, and present-day contribution of wild ruminants to enteric methane emissions in the United States”, J Anim Sci. , 2012.
  2. Song, M, et al, “Association of Animal and Plant Protein Intake With All-Cause and Cause-Specific Mortality,” JAMA Internal Medicine, 2016
  3. [3]. Mann, G, , “Atherosclerosis in the Masai”, Amer J Epid, 1972.
  4. Caterina, R, “n–3 Fatty Acids in Cardiovascular Disease”, NEJM, 2011.

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