Richard H. Schwartz
Vegan, climate change,and social justice activist

What is Our ‘Natural’ Diet?

     Clearly human beings are not carnivores, but are we omnivores or herbivores? Actually we are both. We are omnivores in practice, with most people eating from both the plant and animal kingdoms. However, physiologically and emotionally  we are herbivores as explained below. The difference between our eating habits and our natural conditions and inclinations are why so many people are suffering and dying from heart disease, cancer, and other life-threatening diseases.

    The following comparisons support the conclusion that humans are meant to be herbivorous:

1. Our small and large intestines, like those of primates, are four times longer than those of omnivores. Because of the long intestines, meat passes very slowly through the human digestive system; it takes about 4 days during which the disease-causing products of decaying meat are in constant contact with the digestive organs. Vegan food takes only about 1 1/2 days, and this is sufficient for the vitamins, minerals, and other nutrients to be absorbed.

2. Unlike omnivores, humans do not have claws that can rip flesh, but hands for picking vegetables, fruits, leaves, flowers, seeds, etc.

4. Our saliva is alkaline like that of the higher species of apes; it contains ptyalin to digest carbohydrates. Omnivores’ saliva is acidic.

5. Unlike omnivores, humans do not have long, hard, dagger like teeth for biting into flesh. Our so-called canine teeth are not truly canine like the dog’s. 

6. Omnivores have proportionally larger kidneys and livers than humans have; they need these larger organs in order to handle the excessive nitrogenous waste of a flesh diet.

7 The stomach acids of omnivores are 20 times stronger than that of human beings.

8. Humans are not constituted to prey upon animals, rip apart their bodies, or bite into their flesh. While the gorge of a cat, for instance, will rise at the smell of a mouse or a piece of raw flesh, but not at the aroma of fruit, we shudder at the thought of pouncing upon a bird or other small animal, tearing its still living body apart with our teeth, and eating it.  On the other hand, a bunch of luscious grapes makes our mouth water, and even in the absence of hunger, we will eat fruit to gratify taste.

     Based on the above, there would be a major reductions in diseases if people shift from animal-based diets to plant-based diets. This would have many additional benefits including reductions in climate change, other environmental problems, the current massive mistreatment of farmed animals, hunger, and the very inefficient use of land, energy, water, and other resources.

      Some scientists disagree with the above analysis. They assert that people’s natural diet is omnivorous, consisting both flesh and vegetarian foods. They point to the many years that our ancestors have eaten meat and the fact that primates, the animals whose systems are closest to ours, have been observed to eat meat.

In response:

1. Certainly people have eaten meat for many years. According to the Bible, after first giving people a vegan diet (Genesis 1:29), as a concession to human weakness, God gave people permission to eat meat after the devastating flood in the time of Noah (Genesis 9:3). Just as an automobile will travel on a fuel which is not most suitable to it, people can live on a diet that is not ideal. The issue is not what people eat now and have eaten in the past, but the diet that is healthiest for people and is most consistent with our anatomy, physiology, and instincts. It should also be noted that a significant portion of people throughout history either ate no meat at all or ate it only on rare occasions. In addition, meat contains no essential nutrients that cannot be obtained from plant sources or, in some cases, by supplementation, made necessary by the heavy use of pesticides in modern agriculture. .

2. With regard to primates eating meat, this issue has been hotly debated. Some species have never been observed to do so. Primatologist Jane Goodall’s studies of apes showed that meat eating incidents are extremely rare, and they are unusual and atypical of the species in general, occurring in un-chimplike surroundings. The staple diet of primates is vegan.

     Even if people were omnivorous, that would mean that we have a choice as to whether or not to eat meat. It would leave all the ethical arguments – compassion for animals, helping the hungry, protecting the environment – on the side of vegetarianism and veganism.  Also, if we consider the diet that is best for our health, there is abundant evidence that veganism is our ideal diet.

     So, while human beings are capable of ingesting a wide range of foods, including meat, and while they have been eating meat for many years, modern research shows that we do best on a diet with no animal protein and fat, our ‘natural’ diet.

About the Author
Richard H. Schwartz, Ph.D., is the author of Judaism and Vegetarianism, Judaism and Global Survival, Who Stole My Religion? Revitalizing Judaism and Applying Jewish Values to Help Heal our Imperiled Planet, and Mathematics and Global Survival, and over 200 articles and 25 podcasts at He is President Emeritus of Jewish Vegetarians of North America (JVNA) and President of the Society of Ethical and Religious Vegetarians (SERV). He is associate producer of the 2007 documentary “A Sacred Duty: Applying Jewish Values to Help Heal the World.” He is also a Professor Emeritus of Mathematics at the College of Staten Island, which is part of the City University of New York.
Related Topics
Related Posts