Sacred Cow by Diana Rodgers and Robb Wolf

Rating: 6/10

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High-Level Thoughts

A densely packed book of information on meat and health, ethics, and the environment. Great if you're already bought in to the benefits of meat and want some data, but I think it'd have a hard time convincing a skeptic. I'm also having a hard time verifying some of their claims, so it warrants further research.

Summary Notes

Exec Summary

Meat & Health

  • Most indigenous populations eat a mix of meat & plants. None eat all plants.
  • Since the 70s our beef consumption has dropped, sweeteners, grain, vegetable oils all way up
  • Evidence for longevity from cutting out meat is weak, good counter argument with the Mormons.
  • Very little evidence for benefit of grass feed over grain fed for health, the Omega 6:3 ratio is negligible in absolute quantities.
  • Beef don't absorb glyphosate when they eat it

Meat & The Environment

  • Concentrated feces in a factory farm can't be broken down by dung beetles the way pasture manure can, which is why the methane production is so much higher.
  • Most methane production comes from Fossil fuels, fires, and wetlands farming. Agriculture is negligible.
  • Livestock are only 3.9% of all GHG emissions.
  • Beef and ruminants only get around 10% of their diet from food that's edible to humans.
  • Chicken and Pork eat almost entirely human edible food now, so they stress the system much more.
  • 60% of agricultural land is grazing land, can't farm on it.
  • Beef only get 2-8% of their water from Blue Water, the rest is Green Water that would have been there anyway.
  • Rice takes 410 gallons of water to produce, beef 280.


Beginning about ten thousand years ago, in the first agricultural revolution, human societies gradually transitioned from hunting and gathering to farming, and we began to rely more heavily on crops. Because animals were valued as labor (oxen for plowing) and grains were cheaper, eating meat was more celebratory or sacrificial and symbolic. (Page 12)

Compared to other primates, we have larger brains, shorter large intestines, and longer small intestines. (Page 27)

We need nutrients that are found in both plants and animals. A study in the American Journal of Clinical Nutrition evaluated the diets of 229 hunter-gatherers and found that most ate somewhere from 45 to 65 percent of their calories from animal foods and the rest from plants. This practically fifty-fifty mix allows for the most variety of nutrient intake, since humans do need quite a few nutrients to thrive. (Page 28)

In reality, we're not eating anywhere close to 265 pounds of meat per person, per year. In 2016, when adjusted for loss, Americans ate an estimated 1.8 ounces of beef per day (40 pounds per year), 1.4 ounces of pork per day (31.6 pounds per year), and 2.6 ounces of poultry per day (59.8 pounds per year). (Page 31)

Consumption changes: (Page 32)

  • Since 1970 our intake of beef has actually declined from 2.7 ounces per person per day to 1.8 ounces per day in 2016, while our poultry intake has more than doubled.
  • We've increased our intake of caloric sweeteners
  • our intake of grain products has gone up about 30 percent (and by grains, we're not talking about pearl barley; this is largely ultraprocessed foods made from wheat and corn).

A systematic review of the current research against beef published in the Annals of Internal Medicine surprisingly concluded that the evidence against meat is of low quality, and we in fact don't have the evidence to make public health recommendations to limit red and processed meat consumption. (Page 40)

Coke wants the "official" story to be that what you eat (and drink) does not matter, what matters is how much you exercise." But research shows the opposite; you can't out-exercise a poor diet. (Page 49)

Over nine thousand hospitalized mental patients were fed either a diet rich in Saturated Fat or a diet in which the saturated fat was replaced with Polyunsaturated Fat from Vegetable Oils. The patients fed vegetable oils showed a decrease in cholesterol levels but, interestingly, no decrease in mortality. In fact, the opposite was seen; the patients fed vegetable oils were more likely to die during the study period than those fed saturated fat, who coincidentally had higher cholesterol levels. (Page 53)

A study that looked at people who shopped at health food stores (a change that would seem to account for some of those healthier lifestyle factors) found no difference in mortality between vegetarians and omnivores. (Page 61)

What about those Seventh-Day Adventists? When compared to the typical American omnivore, these studies show that the Seventh-Day Adventists are less likely to have cancer or heart disease or to die from any cause. But they're not factoring in the fact that this population doesn't drink or smoke, has strong community, and lives a very healthy lifestyle overall... It turns out that Mormons practice very similar lifestyle habits to the Seventh-Day Adventists [but eat meat]. Three studies looking at the longevity of Mormons all showed that this group has significantly better health and longer life spans than typical Americans. (Page 62)

Chicken Liver, Salmon, and Oysters are among some of the most nutrient-rich animal foods available, providing large amounts of B12, iron, zinc, and DHA, which are commonly deficient in a diet excluding meat. (Page 71)

Organ Meats are high in vitamin B12, folate, and iron. They are also extremely high in fat-soluble vitamins such as vitamins A, D, E, and K. (Page 73)

We know many may point toward the lower ratio of Omega-6 to Omega-3 as evidence of superiority [of Grass-Fed Beef to Grain-Fed Beef], but look at the absolute amounts. If you eat a kilogram of beef (2.2lbs), then you are still getting only 3.2 grams of omega-6 fatty acids in conventional beef. That's three times less than the quantity supplied by an ounce of walnuts10 and roughly equivalent to an ounce of almonds. (Page 75)

Beef from cattle who eat feed with Glyphosate show the same negligible concentrations of glyphosate as beef from cattle who never ate glyphosate. Glyphosate in the feed of cattle doesn't even appear to negatively affect their body composition or metabolic health. Certainly, there exists a risk that other toxicants do present in greater concentrations in beef from conventional cattle, but we don't have any evidence of this. (Page 79)

Nuts and seeds are an excellent source of minerals, including magnesium, manganese, copper, selenium, and zinc. But relying only on nuts as your primary source of these minerals can have a few downsides. Most nuts are high in Omega-6 fats, which are already found in excess in many of our diets and compete for absorption of anti-inflammatory Omega-3s. (Page 93)

A big reason soy intake is subject to so much research and controversy is because Soy is high in Antinutrients, particularly Isoflavones. These plant compounds are similar to Estrogen and are used by the soy plant as a natural defense, disrupting the reproductive cycle of livestock that eat it. Some research has suggested that isoflavones could result in a disruption in fertility, hormone balance, and thyroid function in humans. (Page 96)

Traditional cultures that consume a lot of soy-based products tend to ferment or prepare the soy in a manner that reduces the content of the antinutrients, reducing the risk of toxicity. (Page 96)

People with allergies to soy can be triggered by Soy Lecithin, which is hidden in foods as a common emulsifier." Soy lecithin may also impair cognitive function and impact brain chemistry. (Page 96)

It found that although greenhouse gas emissions would be reduced by a mere 2.6 percent, we would create a food system incapable of meeting our nutritional needs. In their plant-only system, the US would produce 23 percent more food, but we would be lacking in nutrients. A plant-only system would result in deficiencies in calcium, vitamin K, vitamin D, choline, and essential fatty acids. It would also result in a 12 percent increase in total calories. Our food system doesn't have a problem producing calories (human "feed"). What we need is nutrients. (Page 98)

Among the most concerning nutrient deficiencies prevalent in the vegetarian and vegan population is vitamin B12: 60 percent of adult vegans have been found to be deficient in B12, as well as 40 percent of vegetarians. A deficiency in B12 can cause depression, psychosis, and cognitive impairment. A deficiency in B12 can lead to irreversible consequences for children, including delayed cognitive development, lower academic performance, nerve damage, and failure to thrive. (Page 100)

It's well known that the fatty acid DHA is needed for brain development in infants. However, DHA is absent in a vegan diet without supplementation. Among vegan women, one paper found that the DHA content of their Breastmilk was 69 percent lower than that of mothers who ate animal products, and another study showed that babies born to vegetarian mothers had lower DHA in their blood than babies born to meat-eating moms. (Page 105)

One of the markers of healthy pregnancies and adequate nutrition is Male Female Sex Ratio; on average, there are 105 male babies born for every 100 females. Malnutrition and lack of adequate calories during pregnancy has been identified as one cause of lower sex ratios. A 2000 study of over six thousand pregnant women found that those who followed a vegetarian diet had a considerably lower sex ratio when compared to those who followed an omnivorous diet and were 23 percent less likely to give birth to a boy. Could this indicate that vegetarian diets during pregnancy don't supply adequate nutrition? The low birth ratio of vegetarian women may be an indication of physical stress caused by this eating pattern and threaten fetus viability. (Page 105)

The meat group showed remarkably more physical ability, leadership, and physical growth during the study period. Those who only received the milk substitute lagged behind the meat group aspect. The researchers believe that these results may be related to the impact milk has on iron absorption, which influences cognitive ability. They also suggest that the improvements in performance in the meat group could be due to the intake of high-quality protein, vitamin B12, zinc, and iron in the children's diet, all of which have a positive impact on development. Although this is only one study with some limitations, it's the only controlled study on meat in children, and basically, it suggests milk can't replace meat. (Page 108)

Although this "sixty harvests" number sounds like a convincing statistic, when we looked for the root science on this topic... there was none. It might be tempting to use the Malthusian prediction to cement our position, but the number appears to have been related off the cuff at a conference. (Page 122)

Concentrated animal feces from factory farms are a much different environmental issue than scattered cattle poop, urine, and hooves across grasslands in a natural system. In well-managed systems without a lot of antibiotics or drugs given to the animals, large dung beetle populations are reestablished. These dung beetles help break down manure, and recent studies found they help to mitigate methane emissions from it. How do they do this? Methane is produced in low-oxygen environments. As they tunnel through manure, dung beetles provide ways for oxygen to circulate, preventing methane formation. (Page 136)

If you look into this a little more, you'll find a shockingly high percentage comes from wetland rice production: 6 to 29 percent of human-generated methane emissions and 2.5 percent of overall global anthropogenic emissions. (Instead of Meatless Mondays, should we call for rice-free Fridays?) (Page 137) Methane

According to a recent NASA study, the largest contributors to methane are the fossil fuels, fires, and wetlands or rice farming. One teragram of Methane weighs about the same as two hundred thousand elephants (about 1.1 million tons), and the total amount in the atmosphere is rising at a rate of approximately 25 teragrams per year. The researchers were able to find the exact cause of the recent increases in methane: "The team showed that about 17 teragrams per year of the increase is due to fossil fuels, another 12 is from wetlands or rice farming, while fires are decreasing by about 4 teragrams per year. The three numbers combine to 25 teragrams a year-the same as the observed increase." (Page 137)

According to the EPA, all livestock only represents 3.9 percent of GHG emissions. Within the livestock category, beef cattle only represent 2 percent of total GHG emissions. (Page 140)

Now, in the case of Chicken and Pork, we are talking about a highly energy-intensive process that diverts what is ostensibly human food into animal food, but this is almost purely grains and legume products such as soybeans. With beef, it's quite different. When looking at what only ruminants eat, the numbers are even lower for grain, at only 10-13 percent of the diet for cattle, globally. Grass and leaves makes up 57.4 percent of global ruminant feed rations. The rest is inedible by humans, like "crop residue" such as cornstalks. (Page 150)

Over their life span, typical cattle only get 10 percent of their diet from grainThis means that about 90 percent of the feed for beef is inedible by humans. Let's ruminate on that for a moment: Cattle convert grass and other nutrient-poor food into nutrient-dense food for humans. This is something ruminants are really good at doing. They're upcycling nutrients! One study found that "cattle need only 0.6 kg of protein from edible feed to produce 1 kg of protein in milk and meat. Cattle thus contribute directly to global food security." (Page 152)

Approximately 60 percent of the world's agricultural land is grazing land. Much of this land is not suitable for growing crops and is in fact appropriate only for some type of grazing, whether that be by cows, camels, bison, or goats. (Page 160)

Beef requires only 280 gallons of Blue Water per pound, which is less than the amount required to produce a pound of Avocados, Walnuts, or Sugar. (Page 172)

In typical Beef production, the Green Water number is about 92 percent of the total water calculation. This means 92 percent of the water attributed to beef production is rain that would have fallen even if the cattle weren't alive. In grass-finished beef, the green water number is closer to 97-98 percent. (Page 173)

A pound of rice requires about 410 gallons of water to produce. Avocados, walnuts, and sugar have similar water requirements. Globally, 30 percent of groundwater intended for crops is used by rice, followed by wheat (12 percent), cotton (11 percent), and soybeans (3 percent). (Page 175)

There have been several attempts to calculate how many critters die in field harvest. How many deaths are you causing per calorie you eat? At forty rodent deaths per acre, and six million calories per acre of wheat, that's 150,000 calories per rodent life. Let's be generous and assume only one head of cattle per acre yields approximately five hundred pounds of beef. At approximately 1,100 calories per pound, that's 550,000 calories per cow life! (Page 198)

"In contrast with crop farming, which produces sporadic, seasonal, perishable products, livestock is an asset that can be maintained for short or long periods of time then quickly converted to food or cash when needed." Since crop farming requires not only good land but harvest at a specific time, it's a far less reliable and insecure source of food. (Page 219)

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