Will Ruminant Cattle Save Us?

Source: Beef magazine


After reviewing Can Fixing Dinner Fix the Planet by Dr. Fanzo in my last blog post, a friend replied with a post about “Sacred Cow”, a book and movie with a very different take on eating beef, basically saying that cattle can help save the planet. The argument was all very well researched and referenced. This left me in quite a quandary. Did I get it all wrong in saying that we should be eating less beef in that last post?

I have spent a lot of time tracking down a very complicated story. In fact, I think that I am going to have to start all my blogs from here on with the mantra, “It’s complicated.” Here is the complicated and intriguing version of what I found. Like so many things in our world these days, it is not black or white, and if we are not patient enough to listen to the full nuanced story, then we are not in a position to give meaningful relevant answers. I don’t say this to criticize one side or the other. Like almost everyone, I would really like short sound-bite sized answers. But that is not the world we live in. So here is a somewhat middle ground complex answer that I have come to that will probably not satisfy everyone but is the most honest answer that I can find at the moment.

First, I will explain some basics about protein nutrition with a summary of my last anti-beef post. Then a summary of the Sacred Cow pro-beef position with some pros and cons with some basics about ruminants and how they can benefit us. Then a dive into some of the complex issues surrounding the multiple uses of farmland, the conflicts with ethanol production from corn, the contribution of non-meat animal products like dairy and eggs, first world vs third world needs, and the contribution of fish to human protein nutrition. With all that in mind we will try to answer the question, should we eat less beef or meat?

Protein Basics

First, let’s start with a quick review of the basics of what humans need in terms of protein. The generally accepted wisdom among nutritionists is that adult humans require about 0.66 grams of mixed source protein per kg of body weight per day. When we convert that into the Recommended Dietary Allowance (RDA), we bump that up a bit to 0.80 g/kg to make sure that we cover everyone, even those with unusually high needs, and then we multiply it by an average body weight to give us the official RDA of 56 g/day for adult men and 46 g/day for women. We tend to bump that up some for pregnant women, for people who are aggressively weightlifting, for vegans, and for the elderly who are not metabolizing protein so well. But for most folks 19-70 years old, the RDA is just fine. How does that compare to what us Americans actually consume? On average, adult women in the US consume about 70 g/day and men consume about 100 g/day. So, when you hear that people are not consuming enough protein, please remember that we are already consuming about twice as much as we require.

Here are some finer details if you care to know. Proteins are made up of 21 amino acids, about half of which we require in our diets because our bodies do not synthesize them directly. Animal sources of food generally have all these required amino acids; not so much for the plant sources such as beans and other vegetables. But if you are a vegan and if you eat a varied diet with grains and beans and veggies and fruits, then you should be just fine, amino acid-wise. Your protein requirements are a bit higher than described above since the plant protein quality is a bit lower.

Low Beef Basics

In the previous article I agreed with the author of the book I reviewed in recommending that we all should eat less beef. I will quickly summarize from the previous review of Can Fixing Dinner Fix the Planet. I said then:

While ruminants (mostly cows) can be raised on pastureland, only about 1/3 worldwide are and almost none in the US are. Beef comes at an enormous environmental cost. It takes up to 30 pounds of grain to get a pound of beef. Other meats, including pork and poultry are more efficient. This is grain and land that could be used for human food directly. You may have heard about “cow farts” and how they contribute to greenhouse gases; a true fact, except that it is actually cow burps. About 40% of all greenhouse emissions related to the livestock industry come from this source.

Thinking more globally, Dr. Fanzo continues, “When health and sustainability align, choices become easier. If beef consumption in high-consuming countries declined to about 50 calories a day, it would nearly eliminate the need for additional agricultural expansion and associated deforestation.”

I am embarrassed to admit now that several facts that I have previously written are misleading and several are complicated and need some explanation that will follow. One misleading statement is that none of US cattle are raised on pasture. In fact, most are raised on forage and other ingredients most of their first year. Forage can be grass in the field or grassy type products that are cut and stored for later use. Most beef cattle are “finished” for the last few months of their lives in feed lots where they are fed a very nutritious diet that includes ground corn and other food concentrates. The other misleading fact is in the 30 pounds of grain per pound of beef. This is based on the assumption that cattle are fed only corn or other grains. As you will see below, this is wrong on several counts.

Sacred Cow Basics

I listened to an hour-long talk by Diana Rodgers, RD on YouTube that was very well presented and, in many places was well documented and well referenced. She favors grass-fed beef production, and she contends that ruminants will help save the planet and our health. While I do disagree with some of her points, I want to compliment her on her diligent research on the topic of meat and health. There is also a book and movie by the same title, Sacred Cow. From the website, she states, “Our hope is to create a new dialogue examining our cultural bias against cattle, pointing out the importance of red meat to our food system and how well managed grazing animals are one of our best solutions to repair the damages of our industrial agricultural system.”

Here are some issues I had with Ms. Rodgers’s presentation. She contends that adults in the US are only consuming about 2 oz of beef a day. I thought that was rather low. I found this fact was rather hard to pin down. The Big Ag folks contend it is about 3.6 oz per day while estimates from government intake data (NHANES) estimate about 2.4 oz per day. But even at 2 oz per day, that comes to 46 pounds a year.

Without a lot of supporting data, she recommends an animal protein intake of about 1.6 g/kg/day. This is twice the RDA and has very little support among other dietitians and nutritionists.

Ms. Rodgers contends that ruminants are the best caretakers of our native grasslands and are the true carbon recyclers of the planet. There are some truths here. The problem is that in the US not all cattle are raised and finished this way. She and I would probably agree that currently in the US, cattle are not a “…well managed grazing animal”, as she aspires from her website. I will also contend below that her solution for well managed grazing animals may be a better solution than she intended.

Two facts that she presents are verifiable and supported by other research and publications. Only 4% (give or take) of the greenhouse gas in the US is from methane from cow burps. However, in the larger picture, global greenhouse gas production from the entire cattle and cow (beef and dairy) industry is 14.5% of the total. In fact, per kg of animal protein produced it would appear that beef cattle are still the major contributors of greenhouse gases compared to other animals and animal products we consume.

Source Kilogram of greenhouse gas emitted per kg of protein produced by each of these food sources.
Note the extreme amount produced by cattle.

But, as Ms. Rodgers contends, as much as 90% of what cattle eat is inedible by humans. This leads to my own confusion about consuming beef mentioned at the start. Why is eating beef such a problem? We often compare the efficiency of raising cattle to other meat sources, such as chickens and pigs. Only 9% of the corn crop in the US goes directly to cattle, while about the same goes to pork and chicken. These are all worth considering as we weigh the importance of eating less beef and less meat overall. A United Nation FAO report of livestock production yielded this graphic of food sources for livestock. Note that only 13% is Grains and 1% Other edible. That leaves 86% inedible. However, that 13% of animal food from grain is actually 32% of the overall global grain production.

Of the 6.0 billion tons of feed used for cattle each year, these are the percentage breakdown of where that feed comes from across the globe.

Ruminant Properties

Ruminant animals include cattle, bison, sheep, goats, and deer. Their unique digestive system allows them to utilize cellulose from grasses and other sources. They derive nutrition from these foods that other animals, including pigs, chickens, and humans cannot benefit from. In the economy of agriculture, this is a great benefit to us humans. We can feed ruminants plants we can’t eat like grass and corn stalks and hay. They turn this into meat and milk, and we benefit. Note that in the graph above, 46% of livestock food around the world is grass and leaves. While I was not able to independently confirm the following calculation, the following quote makes sense from what we have seen so far. “For every 0.6 pounds of human edible protein cattle consume, there is a return of 1 pound of human edible protein in the form of beef.”

Multiple Use Complications

Ruminant nutrition is beneficial to humans. Material that is inedible to humans can be made into food that humans can benefit from. But let’s add another complication that I will not delve too deeply into here since it desires an entire episode. This is the “Fuel vs. Food” controversy. Some of what we feed to cattle is the by-product of the fermentation process of turning corn into ethanol for use as fuel for our cars. About 1/3 of the domestic US corn crop is currently being used for this purpose. So, the fuel and the cattle industries have this interesting synergism. One literally feeds the other.

Here is another way to look at the graph above. If there were no livestock industry and no ethanol industry to feed it, how could all this land and these products be turned to human benefit? The argument is often made truthfully that much of the grassland around the world is not usable for anything else except grazing cattle. But is this true everywhere, especially in the US? If less corn was going to ethanol, could more land be used for other things than corn and soya? I suspect so. Or could that corn and soya enter the global market and bring the price down for children in Kampala, Uganda?

Rich vs Poor Country Complications

There is a complication here on the protein needs of rich countries and poor countries. Rich countries such as the US consume more protein, especially animal protein, than needed. Poor countries are generally in need of protein. One size does not fit all. While many folks, including me, suggest that rich countries should reduce their animal protein intake, we need to consider ways to encourage protein intake in poorer countries, including livestock production especially on marginal land that is otherwise not useful for other agricultural purposes.

Land Use Complications

Generally speaking, grain crops go to one of three things, human dinner plates, fuel production either as ethanol or as biodiesel, and animal feed. At this point, about half of the grain production in the world is going to fuel and animals and half to humans. About a third goes to animals and this creates some interesting math that has been missed by some authors, including Dr. Fanzo, the author of Can Fixing Dinner Fix the Planet. Also misguided was the author of an influential academic article from 2013 that suggested ways to increase food production by reducing livestock. These authors, using data on the conversion of animal food protein into human food protein, found beef production to be incredibly inefficient at 5%. This 5% means that when 20 pounds of protein in grain is fed to animals, only 1 pound of animal protein is produced for the market. This is a common misperception and does not consider the ruminant advantages of cattle and the 86% non-human food sources of livestock production. The conclusions about beef in many of that academic source (cited by others almost 700 times) are erroneous for this reason.

But there is another side. National Geographic did a nice spread on the challenges of feeding 9 billion people in the future. One of their nice graphics illustrated the degree to which land was being used to support human food vs animal and fuel-based foods. They show that most of the agriculture in the US and Europe supports animals and fuels while in Africa and India most of the agricultural land is used for people. An FAO article from the UN states that “…26% of the Planet’s ice-free land is used for livestock grazing and 33% of croplands are used for livestock feed production. Globally, livestock provides 25 percent of protein intake and 15 percent of dietary energy.” So, over half of the usable land gives us only a quarter of our protein.

Reproduced from Vox article Dec 16, 2014 that is reproduced from Nat Geo article. This graph shows how crops across the globe are used either for human food or for feed (for animals) and fuel (as converted into ethanol or as biodiesel).


Just a quick bit of context here on the other major source of protein in the human diet, fish. Fish are an interesting “crop” since no one plants seed, fertilized, or patiently grows this “crop.” Frankly, we just go out and grab it, pretty much as fast as we can. Aquatic foods, including fish, comprise 7% of protein intake worldwide. And this has cost us dearly. We are depleting wild fish stocks rapidly. Presently, about half of the fish we consume are raised in aquaculture, closer to the usual model of normal agriculture.

From: FAO. 2022. The State of World Fisheries and Aquaculture 2022. Towards Blue Transformation. Rome, FAO. https://doi.org/10.4060/cc0461en. The fraction of protein in the human diet that comes from various sources.

Dairy and Eggs?

Dairy and eggs are an interesting source of animal protein that does not directly involve the slaughter of animals for food. In fact, they are much more efficient means of producing human consumable protein from feeding grain to animals. Together, eggs and dairy have a protein conversion rate of about 40%. This makes the vegetarian diet appealing from the environmental point of view. The healthiness of these food sources is still debated, but as protein sources in the diet, they rank as exceptionally high-
quality protein. Interestingly, both cultured fish and chickens can be raised with about the same protein efficiency. Pork, the other red meat, is closer to beef in protein conversion efficiency. The trouble with pork is that pigs are fed on mostly human-edible grains like corn and soy and do not have the ruminant advantage. This brings pork much more into the spotlight as a protein source we might consider reducing for environmental reasons. While pigs apparently do not have the methane burps of cattle or the ruminant advantages of cattle, they are still somewhat costly protein sources considering their food sources and land use. They also create quite a bit of waste that often creates environmental issues.

Is meat truly unhealthy?

This is very hotly debated. Many nutritionists, including me, have said for a long time that red meat, and processed meat in particular, is unhealthy. A recent set of articles in the Annals of Internal Medicine by a thoughtful group of international scientists, concluded that the recommendation to eat less red meat was unnecessary and that the science behind it was weak. For example, they surveyed the literature and found that avoiding red meat consumption would lead to about 4 fewer cardiovascular deaths about every 11 years per 1000 people. That means that there would be 4 fewer deaths per 1000 people who ate no meat every 11 years compared to 1000 people that regularly ate meat. Now, in fairness, lots of very smart scientists disagree strongly with these conclusions and it has descended into a deep argument into how best to do nutritional research.

I will spare you the waist deep arcane arguments here, but I come out somewhere in the middle. There are several reasons to believe that these results underestimate the size or truthfulness of this negative meat effect on our health. (A student of mine and I wrote a nice article connecting red meat with diabetes.) But if you have a choice between stopping smoking a pack a day and stopping eating a cheeseburger a day, I suggest you stop smoking. But, if it’s a choice between a cheeseburger and a Mountain Dew, I would drop the burger.

Grass-fed Beef

Diana Rodgers, in her movie and talk, makes a strong argument for raising beef steer on grass pastures. I agree. There are very modest differences in the healthiness of the final beef product for humans but a great benefit for the planet and the market. It avoids the problematic aspects of the current means of cattle production including the erosion problems, over fertilization leading to anoxic rivers and river outlets, noxious concentrated animal feeding operations (CAFOs), the synergism with the ethanol industry, the destruction of the Amazon rain forest, and the possible breeding of resistant bacterial strains. (These were all spelled out in the previous post.) There is simply not enough pasture to raise all the beef we are currently eating. Thus, the price of beef would probably go up by some huge amount, maybe triple. Hamburger might be $10 a pound. This would have enormous effects. Cattle would eat what they naturally like to eat-grass. Corn would be fed to people, not cattle that are being finished. There may be other effects that are a bit more difficult to predict. More marginal land would probably be turned into pasture. The demand for pork and chicken would increase and thus their prices would increase. We already consume twice as much protein as we require. We already are using far more land than we need for these products.

I suggest that we switch to grass-only and let beef compete with other commodities grown on the diminishing resource we call arable land. You might raise the very sensible question, is this even practical or possible? Probably not at present, but somebody must at least put it forward as the most sensible eventual solution. We can move that way in small increments.

Should we eat less beef?

This is the crux of the matter and why you have patiently read through all this so far. Diana Rodgers, the author behind Scared Cow and the Annals authors have assembled some powerful arguments against limiting beef. I respect their research and findings. Rodgers and her crew put together a very impressive film that I watched carefully in its entirety. It does not dwell much on the issues we have raised here. It addresses the question of how we can grow beef cattle sustainably. A compelling picture was painted of entirely pasture-raised animals. If this was the only beef that we raised and ate, then I would be in favor of including beef in the American (and European) diet. We would have a lot less of it and it would cost a whole lot more.

But remember that cattle, grass-fed or not, still contribute greenhouse gases into the environment. Depending on how you count it the beef cost, it is as much as one seventh of the current greenhouse
gas load.

So, I agree with Ms. Rodgers in her rather idealistic conclusion in favor of grass-only beef. I might go further and suggest that we encourage this on grassland that is not suitable for other purposes. Other countries with serious protein needs will need other protein solutions that will still require animal production, including ruminants. One size will not fit all.

Should we eat less meat?

Based on what we have seen here, maybe the even larger question is, should we be eating less of all types of meat? In my previous article based on Dr. Fanzo’s suggestions, I was suggesting less beef, but here I am going to widen that based on the research presented here. For the sake of our health (less than before, but still an issue) and the sake of the planet (think of land use, greenhouse gases, and energy use) and the needs of 8 billion neighbors, we Americans do not need all the animal protein we consume. We can easily fall back to eggs, dairy, and maybe a little chicken and cultured fish for our limited animal protein need, eschewing red meat (beef, pork, and lamb) and do everyone a favor.


We have come full circle. We started by doubting the conclusions from my previous review of Dr. Fanzo suggesting we eschew beef completely. We found some weaknesses in her and other’s arguments. We found our true requirement for protein, and we discovered the benefits of ruminants. We learned about the number of resources and amount of land that go into livestock. I have concluded that grass-fed beef does solve many of the problems raised previously. I am now concluding that the need is there to reduce all our red meat consumption for the same three reasons as we started with, our health, the planet’s health, and our 8 billion neighbors. Yes, it is indeed complicated.

3 thoughts on “Will Ruminant Cattle Save Us?

  1. Thank you, Martin, for your honest assessment of this complex issue. For the past 18 months our family has focused on a lower-carb diet, especially eliminating processed sugar. Typically this leads to higher meat consumption since pastas are a higher carb food. What ideas do you have to achieve a proper protein balance without additional meat consumption, especially beef and pork?


  2. Martin,
    Your fans are ready for a new health and nutrition posting addressing more recent information about alcohol consumption.


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