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 All Thumbs Book Reviews
Nutrition and Evolution
By Michael Crawford and David Marsh
Review by Sally Fallon
We hate to give this book a Thumbs Down as it contains a fascinating
and important discussion of the essential role that animal foods play
in human diets. The fact that the authors end up by condemning butter
and recommending commercial vegetable oils shows how political correctness
can lure modern writers down the wrong path, forcing them into conclusions
that completely contradict the major premises of their argument.
The thesis of Crawford and Marsh is that exposure to the appropriate
chemistry allows the various species to develop. Animals could not develop
on the earth until plants had produced enough oxygen for them to survive.
A major difference between the carnivore and the herbivore is the
design of the eye--a difference that is explained by the availability
of nutrients to the two categories of animals. Carnivores like cats
and owls--and humans--are amazingly efficient in dealing with different
degrees of light. Our eyes can see a small light on a dark night miles
away and also adjust to see clearly in a bright light. Why is it that
animals that are preyed upon, like antelope and mice, do not have this
range of vision, even though it would be to their evolutionary advantage?
The answer comes from the availability of vitamin A in the diets. The
first sign of a vitamin A deficiency is failing night vision. Crawford
and Marsh point out that this was discovered after the First World War
in Denmark, when the country exported all of its butter to earn foreign
exchange, using margarine for home consumption. Many Danish children
developed blindness, a tragic occurrence that led to the fortification
of margarine with vitamin A. (Even consumpton of fortified margarine
can lead to poor eyesight, because margarine lacks very long-chain omega-3
fatty acids and the trans fats it contains can interfere with visual
development.) Herbivores make some vitamin A from carotenes in the plants
that they eat, but predators get preformed vitamin A from the organ
meats of their prey, which they eat preferentially. In fact, cats, the
ultimate predators, cannot make vitamin A from carotenes at all.
There is a limit, say the authors, to the level of organization that
any particular animal can achieve and also to what it can pass on through
its genes. Many genes are required for an animal to be able to make
vitamin A. If a cat had to synthesize its own vitamin A, it would take
up a significant amount of "disk space," to use terminology from the
realm of computers. Instead, cats delegate the complex vitamin-A-conversion
process to their prey. "At one meal, they can take in the whole supply
of vitamin A that their victim has accumulated over a lifetime, and
do so at low cost to their own organization."
It is delegation of this kind that has allowed the whole hierarchy
of animal life to build up. Like cats, humans must rely on lower orders
of animals for vitamin A, for complete protein, and for essential fatty
acids and their elongated forms. We need these components in our diet
today as much as we did in the past, because our genetic makeup has
not changed.
Obviously, new components in the diet, like sugar and white flour,
are a prime contributor to disease. But Crawford and Marsh mention these
in passing, preferring to dwell on the dubious differences between wild
and domestic animals. They wrongly assert that the meat of wild animals
is low in saturated fat and high in polyunsaturates, and that wild animals
do not accumulate body fat. Formerly butter was a food for the rich,
they say (after noting that butter was a common food in Denmark), and
not part of the diet of the common man.
So along with sugar and white flour in modern diets, the authors finger
saturated fats as something new and detrimental. In fact, it is the
polyunsaturated vegetable oils they recommend that are new and detrimental,
not stable saturated fats. They claim that saturated fats (and sugars
and carbohydrates which are converted to saturated fats) "swamp the
essential fats. . . and then reduce their amounts" resulting in "vascular,
nervous and immune system disorders." In fact, saturated fats support
the body's use of the essential fatty acids and facilitate their conversion
into the elongated forms. Furthermore, saturated fats like butter contain
vitamin A, which humans can make only with great difficulty.
Nowhere is the schizophrenic logic of this book more evident than in
the discussion of Weston Price. The fine dental health and bone structure
of primitive peoples--including those consuming butter and domesticated
meat--is described in detail, and Price's emphasis on the high human
requirements for vitamin A duly noted. This is followed by a lament
for the increased levels of fat "from milk, meat, butter and margarine"
in the Japanese diet, which the authors assert is the cause of the "changes
in body and facial shape" in Japan. Crawford and Marsh seem oblivious
to the fact that the decline in health and degeneration in facial form
in America has occurred during the same period in which we have substituted
margarine and vegetable oil for butter, lard and other nutrient-dense
animal fats.
What can give man hope, say the authors, "is that he alone can look
back and see what made him, and look forward to gauge what that knowledge
implies for his future." Let us look back with the discerning eye of
well nourished carnivores, and not with the confused vision of those
brought up on vegetable oils.
About the Reviewer
 Sally
Fallon is the author of
Nourishing Traditions: The Cookbook that Challenges Politically Correct
Nutrition and the Diet Dictocrats (with Mary G. Enig, PhD), a well-researched,
thought-provoking guide to traditional foods with a startling message: Animal
fats and cholesterol are not villains but vital factors in the diet, necessary
for normal growth, proper function of the brain and nervous system, protection
from disease and optimum energy levels. She joined forces with Enig again to
write Eat Fat, Lose Fat, and has authored numerous articles on the
subject of diet and health. The President of the Weston A. Price Foundation
and founder of A Campaign for Real Milk,
Sally is also a journalist, chef, nutrition researcher, homemaker, and community
activist. Her four healthy children were raised on whole foods including butter,
cream, eggs and meat.
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