900 g of lettuce plus 450 g of kale provides just 300 kcal or about
15% of calories. Fortunately, however, such high intakes are unnecessary
for nutritional adequacy. Green leafy vegetables and broccoli contain
higher levels of zinc, calcium and protein than fruit and are therefore
an important part of raw diets, but about 500 g per day of green
vegetables, including a mixture of lettuces, broccoli and darker
leaves such as kale and spinach, is sufficient to bring mineral
and protein intakes into line with general recommendations. Such
vegetables also provide vitamin K, which promotes healthy bones.
Other raw vegetables can be useful: for instance, carrots are a
good source of calcium and peas a good source of zinc and protein.
The best balance
between sweet fruit and fatty foods is probably a matter of individual
constitution. Some people experience dental problems with a very
high fruit intake. This can be a particular problem for young children.
Many people will struggle to maintain weight if they do not include
significant amounts of high fat foods. More than 10% of calories
as polyunsaturated fat is not recommended. Olives, avocados, almonds,
hazelnuts and macadamias are all dominated by monounsaturated fats,
which are the safest fats to consume in large quantities. Obtaining
up to 40% of calories from these foods according to individual energy
needs should be perfectly healthful. It is also important to include
a good source of omega-3 fats such as crushed flax seed or its oil.
Selenium can be low if the food is grown in selenium deficient soil,
so a Brazil nut a day provides a useful insurance policy.
fruits, there is no need to rely on unusual or exotic items. Bananas
are a good energy food, being relatively low in fibre and high in
potassium. Oranges are rich in calcium, folate, potassium and vitamin
C. The high potassium and low sodium content of raw vegan diets
reduces the need for calcium by reducing calcium losses and can
be expected to reduce blood pressure and risk of stroke.
raw vegan dietary schools differ in their approach to B12. Some
recommend that B12 supplements should not be taken unless clear
deficiency symptoms occur. David Wolfe (Nature’s First Law) recommends
seven different potential B12 sources, including unwashed or wild
plants, nori, spirulina, fermented foods or a probiotic, with a
B12 supplement as an alternative if these are not available. George
Malkmus has recommended regular use of a B12 supplement since a
study of Hallelujah dieters showed signs of inadequate B12 in most
of them and showed that a B12 supplement or fortified nutritional
yeast corrected this reliably while probiotics did not.
confusion in this area arises from a conceptual error. Many raw
food or natural hygiene advocates believe that our evolutionary
diet and that of our great ape relatives did not include an external
source of B12 and then conclude that humans shouldn’t need such
a source. In fact, all the other great apes - even the gorillas
- consume insects incidentally along with their normal diet of fruits,
shoots, leaves and nuts. Chimpanzees show particular enthusiasm
for collecting and eating termites, which have high measured levels
of B12. After capture, the blood B12 levels of most primates drops
rapidly when they are fed on a hygienically grown and prepared plant-based
diet. It is therefore not surprising that humans also need an external
source of B12.
of David Wolfe’s proposed B12 sources have been directly tested
and shown to be inadequate. Nori and spirulina failed to correct
deficiency in macrobiotic children and did not maintain adequate
blood B12 levels in a Finnish raw food community. Probiotics did
not consistently correct low B12 availability in Hallelujah dieters.
A UK raw food vegan went B12 deficient while growing his own food
and eating it unwashed: based on measured B12 levels in soil this
is unsurprising. Other proposed sources have not been tested so
directly, but the only two published studies of B12 levels in raw
food vegans both showed inadequate B12 levels. Low B12 levels give
rise to elevated homocysteine levels with an associated increased
risk of many illnesses, including stroke and heart disease, without
any classical B12 deficiency symptoms. In children the onset of
full blown deficiency can be very rapid with much greater risk of
long-term damage or even death. At least 3 micrograms per day
of B12 from fortified foods or supplements is needed to minimise
homocysteine levels in adults. Breast milk is an adequate source
for infants only if the mother’s intake is adequate.
main argument for the desirability of high raw diets derives from
comparison with our evolutionary diet and the diets of our great
ape relatives. All the great apes eat diets centred on raw fruit
(chimps, bonobos, orangutans, lowland gorillas) or raw leaves (highland
gorillas) and including a mixture of fruit (including large amounts
of seeds), leaves, shoots, insects and often nuts. Use of cooked
foods and large amounts of grains is unique to humans. It is further
suggested that a return to a diet more like that of our ape relatives
would bring great benefits to health as it is the diet to which
we are evolutionarily adapted. This is a plausible argument and
the nutrient content of such a diet matches modern nutritional knowledge
in many ways: e.g. high folate, vitamin C, vitamin K, potassium
and magnesium intakes along with low saturated fat and cholesterol.
However, there are important limitations to using the plant content
of great ape diets as a model for ideal human diets.
insects cannot be part of a vegan diet and are probably the key
source of B12 in most primate diets. As all B12 comes from bacteria,
the absence of insects is readily compensated for by using B12 produced
by bacteria in commercial fermenters and used in fortified foods
human exposure to sunlight at high latitudes and when spending most
of the day indoors is greatly reduced compared with our evolutionary
exposure. During the UK winter, vitamin D from foods fortified with
the vegan form (ergocalciferol, D2) can help to compensate for limited
light exposure. A trip to sunnier climes during the winter allows
the vitamin D to be topped up more naturally. Infants are particularly
vulnerable to vitamin D deficiency due to the high rate of bone
building taking place and should always receive a vitamin D supplement
in winter. Breast milk is not an adequate source: we are designed
to live nearer the equator.
the human gut is smaller overall than that of the other great apes
and the human colon takes up just 20% of the digestive system compared
with 50% in the other great apes. This results in a dramatically
reduced capability to process fibre, indicating that humans are
adapted to a lower fibre diet than the other great apes, who consume
several hundred grams of fibre per day. Our palaeolithic ancestors
consumed around 100 g of fibre per day.
copying the other great apes is therefore not an option. There are
three candidate explanations for this reduced capacity to process
fibre: increased reliance on soft fruit, increased consumption of
meat, and increased food processing. The former is unlikely to have
been the primary factor as it represents a restriction of diet rather
than an expansion. Increased meat consumption probably started with
homo erectus about 2 million years ago, but may only have become
a major factor about 20,000 years ago with an explosion in sophisticated
hunting techniques. All the great apes show some use of food processing.
Chimps often use stones to crack nuts and chew fibrous foods to
remove the juice before discarding the fibre.
tool use by human ancestors became common about two million years
ago, but most forms of food processing would leave little trace,
so it is difficult to verify how big a role such processing played.
However, it is plausible that food processing, including cooking,
played a major part in the changes in the human digestive system
compared with the other great apes. Humans may have evolved to rely
on food processing.
processing destroys some nutrients, but can also inactivate toxins
and increase the availability of other nutrients. Conservative cooking
such as steaming or boiling causes only modest loss of some nutrients,
such as folate, while enhancing the bioavailability of others, such
as carotenoids. Lycopene, which appears to have profound protective
effects on health, is better absorbed from cooked than from raw
tomatoes. Liquidising or juicing also increases carotenoid availability
from carrots. Cooking increases the energy available from starchy
foods such as potatoes and grains and inactivates certain food toxins,
thereby increasing the range of foods available to us. Whether such
foods belong in an optimal diet remains to be established. The longest-living
population in the world, the Japanese Okinawans, make extensive
use of cooked grains, sweet potatoes, vegetables and soy products
and little use of raw fruit. However, there is no large group of
long-term raw food vegans to provide a direct comparison.
is good direct evidence that large amounts of refined grains are
associated with increased risk of heart disease and diabetes in
Western populations. However, higher consumption of whole grains
is associated with reduced risk of heart disease and diabetes, so
this evidence suggests that grain should be consumed in unrefined
(whole) form rather than eliminated altogether, at least for most
people. A few individuals have life-threatening adverse reactions
to gluten (present in many grains but notably absent from rice).
The established effects of gluten range from allergies and coeliac
disease to varying degrees of digestive discomfort. In addition,
some individuals appear to metabolise gluten poorly with high levels
of opioid protein fragments appearing in their urine. This pattern,
which also occurs with casein from animal milks, has been found
in some studies to be more common in autistic and schizophrenic
individuals and the symptoms of such individuals sometimes improve
on elimination of gluten and milk. As a raw food diet is often a
gluten free diet, it is possible that some of the people finding
such diets particularly beneficial may be gluten intolerant in varying
food has particular environmental advantages in that it often comes
from trees (avoiding soil loss from tilling) and requires little
packaging and no cooking. These characteristics benefit the health
of the planet and all who share it. On the other hand, raw food
often requires long-distance transportation and commercial banana
production is an environmental disaster with high pesticide use
affecting plantation workers and local rivers. The trade-off is
not clear cut. It is likely that local sourcing of cooked foods
(e.g. Scottish oats) has the environmental edge over Jamaican bananas
or airlifted strawberries, but seasonally available local fruits
and nuts have the edge over both.
recognised effect of a high raw diet is weight loss, and many leading
exponents of raw diets report being overweight on a conventional
diet but achieving a desirable weight on switching to a raw vegan
diet. This effect is no mystery as raw plant foods are generally
low calorie density high fibre foods which are very filling – ideal
for weight loss – and was confirmed by a six-month trial in South
Africa. A common reason for abandoning raw food diets, however,
is excessive weight loss. Including sufficient tropical fruits such
as bananas and avocados, or nuts and seeds and cold pressed oils,
is important for maintaining a healthy weight once any desired weight
loss has been achieved.
the consumption of raw fruits, nuts and salad vegetables considerably
beyond current UK average intakes can be expected to be benefit
individual health and to benefit the environment if locally produced.
However, evidence to date does not justify a general recommendation
of raw vegan diets in the sense of more than 80% of food being consumed
raw, particularly for children who need a relatively high calorie
density. The Vegan Society recommends the consumption of a wide
variety of plant foods, including raw fruit and salads and cooked
foods including a wide range of vegetables and whole grains. It
also strongly recommends the consumption of 3 micrograms per day
of vitamin B12 from fortified foods or supplements for all vegans
and the use of vitamin D supplements for infants during the winter.
example 2000 kcal. raw diet for one day.
100 g red peppers, 200 g tomatoes, 300 g oranges, 200 g apples,
500 g bananas, 100 gpears, 50 g peaches, 50 g raspberries, 200 g
kiwi fruit, 100 g strawberries, 50 g mangos.
leafy vegetables and broccoli: 200 g lettuce, 100
g kale, 100g spinach, 100g broccoli.
foods: 200 g avocado, 30 g almonds, 20 g hazelnuts,
10 g flaxseed, 3 g Brazil nuts
100 g carrots, 100 g peas.
provides 700 mg calcium, 700 g magnesium, 9 mg zinc, 50 g protein,
100 mcg selenium, 3 g omega-3 fatty acids, 8,000 mg potassium, 1100
mcg folate, 2 mg vitamin B1, 2.4 mg B2, 6 mg B6, 1100 mg vitamin
C, 30 mg vitamin E, 6000 mcg of vitamin A (from carotenoids) and
about 1000 mcg vitamin K. It may be too high (80 g) in fibre for
some people, particularly the very old or the very young, and it
contains arguably too little sodium (270 mg). The iodine content
may also be low, depending on the soil where the produce is grown.
of fatty acids is excellent. The diet contains no cholesterol or
trans-fats and just 4% of calories as saturated fat while providing
5% omega-6, 1.5% omega-3 and 18% monounsaturated fat. Intakes of
carotenoids, vitamin C, folate, vitamin K, vitamin E, magnesium,
selenium and potassium are all much higher than in conventional
diets and can be expected to promote health. Zinc and protein intakes
are adequate. The calcium content has been adjusted for the low
availability of calcium from some of the foods, particularly spinach,
and is probably adequate. Vitamin B12 and vitamin D must be addressed