"Humans are most often described as "omnivores." This classification is based on the "observation" that humans generally eat a wide variety of plant and animal foods. However, culture, custom and training are confounding variables when looking at human dietary practices. Thus, "observation" is not the best technique to use when trying to identify the most "natural" diet for humans. While most humans are clearly "behavioral" omnivores, the question still remains as to whether humans are anatomically suited for a diet that includes animal as well as plant foods.
A better and more objective technique is to look at human anatomy and physiology."
Extract:
In conclusion, we see that human beings have the gastrointestinal tract structure of a "committed" herbivore. Humankind does not show the mixed structural features one expects and finds in anatomical omnivores such as bears and raccoons. Thus, from comparing the gastrointestinal tract of humans to that of carnivores, herbivores and omnivores we must conclude that humankind's GI tract is designed for a purely plant-food diet.
SUMMARY
Facial Muscles Carnivore Reduced to allow wide mouth gape Herbivore Well-developed Omnivore Reduced Human Well-developed Jaw Type Carnivore Angle not expanded Herbivore Expanded angle Omnivore Angle not expanded Human Expanded angle Jaw Joint Location Carnivore On same plane as molar teeth Herbivore Above the plane of the molars Omnivore On same plane as molar teeth Human Above the plane of the molars Jaw Motion Carnivore Shearing; minimal side-to-side motion Herbivore No shear; good side-to-side, front-to-back Omnivore Shearing; minimal side-to-side Human No shear; good side-to-side, front-to-back Major Jaw Muscles Carnivore Temporalis Herbivore Masseter and pterygoids Omnivore Temporalis Human Masseter and pterygoids Mouth Opening vs. Head Size Carnivore Large Herbivore Small Omnivore Large Human Small Teeth (Incisors) Carnivore Short and pointed Herbivore Broad, flattened and spade shaped Omnivore Short and pointed Human Broad, flattened and spade shaped Teeth (Canines) Carnivore Long, sharp and curved Herbivore Dull and short or long (for defense), or none Omnivore Long, sharp and curved Human Short and blunted Teeth (Molars) Carnivore Sharp, jagged and blade shaped Herbivore Flattened with cusps vs complex surface Omnivore Sharp blades and/or flattened Human Flattened with nodular cusps Chewing Carnivore None; swallows food whole Herbivore Extensive chewing necessary Omnivore Swallows food whole and/or simple crushing Human Extensive chewing necessary Saliva Carnivore No digestive enzymes Herbivore Carbohydrate digesting enzymes Omnivore No digestive enzymes Human Carbohydrate digesting enzymes Stomach Type Carnivore Simple Herbivore Simple or multiple chambers Omnivore Simple Human Simple Stomach Acidity Carnivore Less than or equal to pH 1 with food in stomach Herbivore pH 4 to 5 with food in stomach Omnivore Less than or equal to pH 1 with food in stomach Human pH 4 to 5 with food in stomach Stomach Capacity Carnivore 60% to 70% of total volume of digestive tract Herbivore Less than 30% of total volume of digestive tract Omnivore 60% to 70% of total volume of digestive tract Human 21% to 27% of total volume of digestive tract Length of Small Intestine Carnivore 3 to 6 times body length Herbivore 10 to more than 12 times body length Omnivore 4 to 6 times body length Human 10 to 11 times body length Colon Carnivore Simple, short and smooth Herbivore Long, complex; may be sacculated Omnivore Simple, short and smooth Human Long, sacculated Liver Carnivore Can detoxify vitamin A Herbivore Cannot detoxify vitamin A Omnivore Can detoxify vitamin A Human Cannot detoxify vitamin A Kidney Carnivore Extremely concentrated urine Herbivore Moderately concentrated urine Omnivore Extremely concentrated urine Human Moderately concentrated urine Nails Carnivore Sharp claws Herbivore Flattened nails or blunt hooves Omnivore Sharp claws Human Flattened nails
Read more: The Comparative Anatomy of Eating - Vegsource.com
