A trip through the body
The External Cues
Finally, take a look at the external differences. Our hands are made for gathering plants, not for ripping flesh. We cool ourselves by sweating, like most other plant-eating animals, rather than panting like carnivores. We drink by sipping, not by lapping like a dog or cat. The exhaustive comparisons of our body traits with those of other animals prove that we have evolved over aeons in an environment of plant-based foods. We were made to be plant-eaters, not meat-eaters. We are now paying the price for straying from our design with chronic illnesses and premature death.
On the tips of our tongues are sensors, designed to seek out sweet-tasting foods – carbohydrates (sugars). While plant foods are full of carbohydrates, there are essentially none in meats of any kind (except for a small amount of glycogen). Carnivores’ tongues have no carbohydrate sensors – they have no need for them. Instead, carnivores’ taste buds are pleasantly stimulated by animal proteins (amino acids) (Li et al., 2005).
From top to bottom, human digestive systems have evolved to efficiently process plant foods. Digestion begins in the mouth with a salivary enzyme called amylase (ptyalin). Its sole purpose is to help break down complex carbohydrates from plant foods into simple sugars. As there are no carbohydrates in meat, true carnivores don’t need this enzyme. Their salivary glands don’t synthesise it.
The stomach juices of meat-eating animals are highly acidic. They have to be, so that they can break down the large quantities of muscle and bone materials they eat.
Much lower concentrations of stomach acid are needed to digest starches, vegetables and fruits. Weight for weight, plant protein requires half the amount of hydrochloric acid to digest it, compared to animal protein. It is also digested in half the time (Lucas, 1979).
Humans and other plant-eaters have much lower levels of stomach acid than carnivores. They are much better equipped for digesting plant foods – and may even increase their risk of stomach ulcers if they do eat meat.
Vegans and vegetarians have fewer peptic ulcers than meat-eaters. This is mainly because their plant-based diets are much easier to digest.
The human intestine is long and coiled, much like that of apes, cows and horses. This makes digestion slow, allowing time to break down and absorb the nutrients from plant foods. In contrast, the intestine of a carnivore, such as a cat, is short, straight and tubular. This means that flesh can be digested very rapidly, and the remnants excreted quickly, before they putrefy (rot). Overall, the intestines of meat-eaters are noticeably simpler than those of planteaters like people. The difference in transit time (time taken for food to make its way from the mouth to the anus) between humans and carnivores is what really brings the anatomical differences home. Humans – even those on a high fibre diet – have an average transit time of almost 41 hours. In stark contrast, the average transit time in a pure carnivore such as the mink, is just 2.4 hours (Milton, 1999)! This means that when people eat meat, it has plenty of time to putrefy (rot) and cause the production of cancer-causing agents.