What a load of rubbish. It's a bit dumb to try and compare humans to meat eaters or herbivores when we are most likely omnivores.
Like the hard-core carnivores, we have fairly simple digestive systems well suited to the consumption of animal protein, which breaks down quickly. Contrary to what your article says, the human small intestine, at 23 feet, is a little under eight times body length (assuming a mouth-to-anus "body length" of three feet). This is about midway between cats (three times body length), dogs (3-1/2 times), and other well-known meat eaters on the one hand and plant eaters such as cattle (20 to 1) and horses (12 to 1) on the other. This tends to support the idea that we are omnivores.
Herbivores also have a variety of specialized digestive organs capable of breaking down cellulose, the main component of plant tissue. Humans find cellulose totally indigestible, and even plant eaters have to take their time with it. If you were a ruminant (cud eater), for instance, you might have a stomach with four compartments, enabling you to cough up last night's alfalfa and chew on it all over again.
Or you might have an enlarged cecum, a sac attached to the intestines, where rabbits and such store food until their intestinal bacteria have time to do their stuff. Digestion in such cases takes place by a process of fermentation--bacteria actually "eat" the cellulose and the host animal consumes what results, namely bacteria dung.
The story is roughly the same with teeth. We're equipped with an all-purpose set of ivories equally suited to liver and onions.
Humans also have forward facing eyes, like most predators.
Looks like we have been eating meat for about 2.5 million years.
The "Seven Deadly Sins"
• Grains (wheat/rice/oats etc) . . . . . • Dairy (milk/yogurt/butter/cheese etc) . . . . .• Nightshades (peppers/tomato/eggplant etc)
• Tubers (potato/arrowroot etc) . . . • Modernly palatable (cashews/olives etc) . . . • Refined foods (salt/sugars etc )
• Legumes (soy/beans/peas etc)