Are We Natural Vegetarians?
A cat
or dog salivates with anticipated pleasure at the sight
and smell of raw meat, but very few humans exhibit this
behaviour. For most meat eaters, their chosen cut needs
to be cooked before it becomes attractive. This is just
one factor that might make us wonder whether eating meat
is natural for us, and whether being a vegetarian is a
realistic option.
Other clues can be found by comparing the anatomy and
physiology of humans with different types of animal. It emerges
that humans are far more similar to fruit and nut eating
animals - vegetariaqns such as monkeys and apes, and to
leaf and grass eating animals such as sheep, cattle, elephants
and koala bears, than to the carnivores.
The following two lists show the characteristics, first of
carnivores, and then of non-carnivores, or vegetarians.
Carnivores generally:
1. Have very short digestive tracts (three times their body
length) to excrete decaying meat waste rapidly.
2. Produce very strong stomach acid - typically 20 times
stronger than that of a non-carnivore - to digest bone, sinews
and large quantities of meat.
3.
Produce small amounts of saliva because digestion does
not begin in the mouth with carnivores.
4. Tend to have jaws that can only move up and down, which
means that they cannot grind their food and can hardly chew at
all. Meat is torn off with their long, sharp incisors and
canine teeth, and is swallowed in large chunks. The teeth are
also shaped and angled to move with a shearing motion to cut
through bone and tough sinews.
5. Show great agility in catching prey, and have sharp claws
and strong jaws to bring down, kill and consume prey.
However, vegetarians - non-carnivorous animals and humans
generally:
1. Have long digestive tracts that are about the same
proportion to body length as in grass-eating animals (12
times). The great length allows the longer period of time that
is needed for fruit and vegetables to be digested
completely.
2. Have weak stomach acid, which is all that is necessary for
the slow digestion of grasses, grains and vegetable matter.
3. Produce a larger quantity of saliva, which also contains the
enzyme ptyalin. The plentiful saliva and the ptyalin begin the
digestion of grains, fruit and vegetables in the mouth.
Carnivores neither eat these kinds of food nor do they chew
their food, which means that digestive enzymes in their saliva
are absent.
4. Have jaws that move with a grinding motion. This grinding
together of the relatively flat teeth reduces the particle size
of the food and exposes it to the saliva and ptyalin in the
mouth. Human canine and incisor teeth are small compared to
those of a carnivore and are, perhaps, better suited to biting
tough vegetables rather than animal skin and bone.
5. Have no claws, relatively weak jaws and not a great deal of
agility. For example, if a chicken is placed in an open space
it would be extremely difficult for a human to catch it; we
don't appear to be designed for that sort of activity.
The evidence seems clear that humans have evolved to eat little
or no meat - to be vegetarian.
Is
Meat Actually Harmful?
Many
people eat meat and appear to survive reasonably well. So
why shouldn't humans eat meat if they want to? Why should
they be vegetarian? There is the moral objection that
animals should not be killed for the benefit of humans.
This argument is complex because, for example, few people
go so far as avoiding shoes and gloves made from leather
- and most of the arguments that apply to leather also
apply to meat. However, leaving the moral argument aside,
there is a very strong reason not to eat meat - it is bad
for our health.
[Next:
Meat Makes Disease More Likely]
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