Research and general acceptanceResearch
FOSSIL AND ETHNOGRAPHIC EVIDENCEAlthough
there have been no large trials of neanderthin or
other paleo diets, there is an increasing volume of
scientific evidence to support the benefits of at least
some components of these diets. Cordain’s paleolithic
diet was based on evidence from the fossil record
and ethnographic studies of 181 hunter/gatherer
groups around the world. This evidence suggests that
the pre-agricultural diet was primarily animal-based,
with 65% of energy from animal sources and 35%
from plant sources—a diet high in protein and low-
to-moderate in carbohydrates and fat. Studies indicate
that early humans rarely if ever ate cereal grains or
diets that were high in carbohydrates. Cereal grains
are virtually indigestible by humans without milling
(grinding) and cooking. The first grinding stones do
not appear in the archeological record until about
10,000–15,000 years ago. Modern hunter/gatherers,
such as African Bushmen, Amazonian Indians, and
Australian Aborigines, have little heart disease,osteo-
porosis, obesity, cancer, rheumatoid arthritis, or
other diseases until they adopt a modern western diet.
Fossil studies have shown that the density and
robustness of paleolithic bones were equal to or
greater than those of most modern humans, despite a
low-calciumhigh-protein dietwithout dairy products.
This has been attributed to their physical activity, with
a daily energy expenditure of twice that of modern
humans,vitamin D from working outdoors in the
sun, and improvedcalciumbalance due to improved
acid-base status from the 35% of energy coming from
fruits and vegetables.
The fossil record indicates that, in comparison to
their paleolithic ancestors, early farmers had:
smaller skeletons
increased infant mortality
shorter life-spans
more infectious diseases
more iron-deficient anemia
more bone disorders
more dental caries and tooth enamel defects.
NUTRITIONAL EVIDENCEThere is little scientific
evidence to support the prevailing view that healthy
diets should be high in complex carbohydrates such as
are found in breads, cereals, rice, and pasta. According
to Cordain:Although individual tolerances for cereal grains vary
tremendously, health deteriorates when cereal con-
stitutes 70% or more of the caloric intake.
Diets high in cereal and dairy lower the pH of the
body, making it more acidic and leading to urinary
calcium excretion and increased depletion of skeletal
calcium.
The high phytate content of wholegrain cereals can
interfere with iron and calcium metabolism.
The high phytate levels in unleavened wholegrain
breads can cause zinc deficiency.
Components of cereals can interact with the gastro-
intestinal tract and perhaps with the immune system.
The high lectin content of whole grains can cause diet-
ary and pathogenic antigens to enter the circulation.
Whole-cereal grains lack vitamin C and beta-
carotene and their vitamin B 6 is poorly absorbed.
Epidemiological studies have shown that diets high
in unleavened wholegrain breads can result in vita-
min D deficiency and rickets.
Whole grains have low levels of essential fats and
high ratios of omega-6/omega-3 fatty acids.
Cordain believes that the modern western diet is
not only too high in saturated fats, but that the poly-
unsaturated fats are out of balance. Cordain’s
research suggests that prior to the development of
agriculture, the ratio of omega-6 toomega-3 fatty
acidswas about 1:1–3:1, whereas in the modern diet
the average ratio is 12:1.
CLINICAL STUDIESA2003Germanstudyfoundthat
a diet high in lean meat and relatively low
in carbohydrates increased HDL (‘good’) cholesterol
and lowered LDL (‘bad’) cholesterol,triglycerides,and
homocysteine levels. They concluded that their results
might warrant a reevaluation of high-carbohydrate,
low-fat nutrition guidelines. Clinical studies also have
shown that people eat fewer calories with high-protein
meals than with high-carbohydrate or high-fat meals,
probably because protein is more satiating.
OPPOSITIONWhile most scientists and nutrition-
ists agree that increased consumption of fruits and
vegetables, reduced saturated fats, and increased
activity levels are beneficial, many of them consider
paleo diets to be eccentric, if not outright dangerous.
Their concerns include:
the elimination of entire food groups
increased consumption of saturated fats that could
raise cholesterol
excess wasted protein
possible weight gain.Neanderthin