Filetype PDF | Posted on 04 Jan 2023 | 2 years ago
Authentication
digital resources
157x Filetype PDF File size 0.38 MB Source: www.cell.com
Current Biology Vol 23 No 9
R354
Guest editorial unanswered that would help carry the Humans cannot survive as pure
integration substantially further — what carnivores unless their meat contains
are humans adapted to eat? Arctic levels of fat in the form of rich
The major consensus solution is the layers of blubber. The meat idea can
The evolution of weakly general claim that, compared at best be only part of the solution for
human nutrition to other primates, our species is an originally tropical animal.
adapted to high-quality omnivorous Second is the hypothesis that
diets. But what does this mean in humans are uniquely adapted to a high
Richard Wrangham terms of biological adaptation? Is proportion of starch in our diets. More
there a particular kind of food item, than 50% of calories worldwide are
This issue of Current Biology addresses or combination of items, that humans estimated to come from starch, and
the biology of food. Scientific and need to thrive? Also, how does the hunter-gatherers in every continent
public interest in food covers many answer to this question affect our regularly exploit starch-rich foods such
different perspectives, but since there understanding of human anatomy as tubers, rhizomes, corms and seeds.
is no discipline of food, food research and physiology? Evolutionary Duplication of human genes for amylase
tends to be carried out separately in anthropologists have mostly focused (a starch-digesting enzyme) support the
such areas as ecology, physiology, their answers to these more specific notion of humans being better adapted
and the neurosciences. The integration questions on food choices, suggesting to starchy foods than the great apes.
promised by Current Biology’s multiple three main kinds of solution. Yet against the supposed importance of
reviews is therefore particularly First, many paleoanthropologists starch as an ancient adaptation, most
valuable. and archaeologists have long argued contemporary sources of starch are
Even areas of investigation with that the dietary specialty of the recently domesticated grains such as
such similar interests as the nutritional human lineage is the inclusion of rice and wheat, whose wild ancestors
sciences and evolutionary biology meat and other protein-rich foods were probably rarely eaten until shortly
can benefit from a closer working from large animals. In favor of this before the agricultural revolution tamed
relationship. Strikingly, despite the fact idea, meat normally makes up 40% them about 10,000 years ago. The fossil
that studies of nutrition and research or more of the diets of recent hunter- record of starch eating is frustratingly
on human evolution emerged in gatherers — certainly a much larger shallow, stretching only to some 50,000
th proportion than in other primates. years for starches trapped in neandertal
parallel in the mid-19 century, and
that both studies are concerned with Meat eating was first evidenced 2.6 dental calculus. Furthermore, humans
biological adaptation including the million years ago, from cut marks do not need starch for survival. Arctic-
importance of food, these sciences on bones about the time of the adapted hunter-gatherers live on purely
have such different aims that they earliest Homo. So meat is indeed a animal-based diets, their intake limited
have never informed each other richly. human specialty. Apparent genetic to protein, fat and a little glycogen
While many nutritionists might be adaptation of apolipoprotein towards found in liver.
interested to know how selection has meat-adaptive variants, and our Third, troubled by the fact that human
shaped human dietary needs and need for vitamin B12 (obtainable only populations can flourish on diets that
adaptability, nevertheless their core from animals) provide supporting are almost meat-free or starch-free,
concern is the public health problem points. Yet meat as a driver of human some anthropologists have suggested
of ensuring nutritional adequacy. And adaptation fits poorly with the small, that variability in diet composition is
while evolutionary biologists might use blunt teeth of humans, the fact that the very feature to which our species
humans as a model organism for some vegetarians thrive, and the even more is adapted. Diet compositions have
studies, human feeding systems with important point that too much meat indeed likely varied over evolutionary
their meals and cuisine and modern protein is physiologically damaging. time, much as they do across the
problems of obesity are too different
from those of other animals to fit easily
into comparisons with other species.
Thus, occasional efforts to reconcile
nutrition and evolution are to be
welcomed, including a book that goes
further than any other in pulling the
two fields together — Evolving Human
Nutrition by Ulijaszek, Mann and Elton
[1]. Ulijaszek et al. document variation
in nutritional needs and food choice
among individuals, populations and
species, discuss theories of how
human diet has evolved, and combine
their review of physiology with societal
problems of food distribution, cultural
norms and globalization. Yet, despite
their thorough approach to seeing
human nutrition in broad overview,
even they leave a core question Figure 1. Cooked evening meals are a universal cross-cultural practice. (Photo: Richard Wrangham.)
Special Issue
R355
world today. However, against the idea food resource [3]. Current evidence caloric equivalence whether or not a
that humans have unusually diverse therefore indicates that humans food is cooked is known to be wrong
diets, in any one location humans eat would be incapable of maintaining a for starch-rich foods, and can be
a greatly restricted range of plants population if they lived on raw foods assumed to be wrong for almost any
compared to great apes. For example, under conditions of hunting, gathering food. So our failure to appreciate the
the flora of southeast Guinea has or growing their own foods. importance of cooking has permeated
been characterized in an area of forest The cooked food solution to the nutrition as much as traditional
and farm bush occupied by about problem of ‘what are humans adapted evolutionary anthropology, and the
20 chimpanzees and 2,500 humans, to eat?’ resolves the difficulties of result has practical implications that
and the diets of both species are well reconciling the unspecialized dentition need to be dealt with. For the billion
known. Out of 664 identified plant and reduced gut of humans with our or more of the world’s poor who risk
species, humans used 11% as food, dietary specialties. Provided we cook, calorie shortage, knowledge of the
compared to 30% for chimpanzees [2]. meat and starchy foods are easily energetic effects of cooking could have
With respect to item diversity, humans chewed with our small, blunt teeth, important consequences.
are better seen as dietary specialists, and they are easily digested with our Calories are only the start of the
not generalists, in keeping with our reduced intestines, which at about problem of what cooking has done to
supposed adaptation to high-quality two-thirds the expected size for our affect our foods and our feeding. To the
foods. body weight are relatively smaller extent that we prefer cooked foods,
If meat, starch and variability cannot than in any other primate. Cooking where do our preferences come from?
of themselves account for human also helps explain how humans can Have our systems of taste, flavor or
dietary patterns at the level of the culturally adapt to a wide variety physical perception evolved in such a
species, each of the three hypotheses of diets in different regions, thanks way that we tend to like cooked foods
can nevertheless be easily incorporated to local cuisines that have been more than raw foods? How important
into a wider solution that I believe has developed to improve different food is the role of cooking in reducing the
not yet been sufficiently explored by types. toxicity or pathogenicity of foods, and
either nutrition science or evolutionary The exciting consequence of to what extent can such effects explain
biology. I suggest that the feature that recognizing food-processing as a our preferences? Have we adapted to
makes humans unique from a nutritional core trait of the human lineage is that mitigate the negative consequences
adaptive perspective is food processing it raises intriguing questions about of cooking, such as the production
in general, and cooking in particular. numerous aspects of our nutritional of potentially carcinogenic Maillard
When cooking began is still uncertain. biology. What, precisely, does cooking compounds or the reduction of some
Biological evidence suggests cooking do to the nutritional quality of food? At vitamins? And how does adaptation
might have been practised first by present we have remarkably little idea. to cooked food affect the evolution of
Homo around 2 million years ago, while Cooking makes starch more digestible, our gut microbiome and its functions?
archaeological evidence of the control but we have only preliminary estimates Such questions suggest that it is
of fire tapers gently away between for the rise in net energy gain (at least time to enrich our understanding of
250,000 and 1 million years ago, leaving 30% for several starchy foods [4]). human nutrition with an evolutionary
no pointers for any specific date of Cooking also seems likely to reduce perspective that takes a new approach
origin. Nevertheless, the times when the costs of fermenting fiber, such to integrating data on humans with
cooking began, or became obligatory, as resistant starches. How much, or studies of other species. Instead of
are largely irrelevant to the question how consistently, cooking increases seeing humans as merely one more
of how humans are now adapted. The the digestibility of proteins and lipids, primate that has an unusual set of food
key point is not when humans became however, is virtually unknown. The choices, we should see ourselves as
adapted to processing their food, but same lack of information applies nutritionally unique. Our dependence
the claim that contemporary humans, to how cooking affects the costs on cooked food sets us apart, and the
uniquely among animals, require of digestion, another process for result is an exciting set of opportunities
cooked food to survive. which we have only preliminary data to make new inroads into old questions
There is much evidence that in indicating that cooking will be found to of how best to sustain ourselves.
order to achieve nutritional adequacy make consistent contributions across
humans need their food cooked — or diverse foods. References
at least a high proportion of it must Considering that cooking is a 1. Ulijaszek, S., Mann, N., and Elton, S. (2012).
be cooked. Cooked evening meals signature feature of the human diet Evolving Human Nutrition (Cambridge University
Press: Cambridge).
are the daily norm in every human that may well contribute 50% or more iyama, Y., and Koman, J. (1992). The flora
2. Sug
culture (Figure 1). There appear to of the net energy absorbed in our of Bossou: its utilization by chimpanzees and
be no cases of humans surviving on bodies, our ignorance about these humans. Afr. St. Monographs 13, 127–169.
bnick, C., Strassner, C., Hoffmann, I. and
3. Koe
raw foods in the wild for more than a topics is astonishing. Equally striking, Leitzmann, C. (1999). Consequences of a
few weeks even when shipwrecked, there is no calorie-counting system longterm raw food diet on body weight and
lost or marooned. And raw-foodists in use that can identify the effects of menstruation: results of a questionnaire survey.
Ann. Nutr. Metab. 43, 69–79.
. Carmody, R., and Wrangham, R.W. (2009). The
(those who deliberately refuse all cooking. The Atwater convention, by 4
cooked foods) tend to be thin and which energy values are assessed in energetic significance of cooking. J. Hum. Evol.
57, 379–391.
reproductively impaired even under food tables in the USA and UK, tells us
the optimal conditions of eating that whether our food is cooked or raw Department of Human Evolutionary Biology,
(and normally lightly processing) is immaterial to the number of calories Harvard University, Cambridge, MA 02138,
domesticated foods from the global per gram dry weight. That claim of USA.
no reviews yet
Please Login to review.
