Debates over the proper human diet tend to get heated quickly, especially when it comes to eating meat. You may hear arguments that humans either are or aren’t supposed to eat meat based on various evolutionary, biological, or ethical considerations.

Depending on whom you ask and what life experiences they’ve had, you could get an answer that ranges from fairly overarching to extremely personal.

This article examines various approaches to whether humans are supposed to eat meat.

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To survive and thrive, living beings are continuously adapting to changing conditions, habitats, and food availability.

DNA evidence stretching back 300,000 years suggests that humans have been continually evolving and adapting to their environments (1).

Thus, as humans are always responding to surrounding conditions, the logic that your body was originally designed to eat a certain food and must stick to it doesn’t stand.

The ancestors of all animals, including mammals, are believed to be carnivores (flesh-eaters). However, countless animals today have evolved to become herbivores (plant/grass-eaters) (2).

In fact, the structure of your teeth demonstrates that humans are omnivorous, or able to eat both animals and plants (3).

Your well-defined incisors — the front four teeth — molars, and premolars are like the teeth of herbivores, designed to cut through and grind plants, while your canine teeth — the sharp ones next to the incisors — are like those of carnivores, designed to rip through flesh.

SUMMARY

Humans have evolved to be omnivorous, eating both animals and plants for survival. However, this evolutionary fact doesn’t mean that you have to eat meat.

In general, humans can eat seeds, fruits, vegetables, roots, and many other plant parts. That said, our bodies aren’t able to digest them all completely.

The outermost layer of every plant cell is the cell wall, which is made of fiber-like compounds like cellulose, hemicellulose, and lignins. You can’t digest these fibrous compounds since you lack the necessary enzyme cellulase (4).

Herbivores like cows, goats, and deer likewise can’t produce cellulase on their own. However, they have friendly gut bacteria that produce it for them — while humans don’t have such gut bacteria (5, 6).

Yet, our bodies produce all of the enzymes, such as protease and lipase, necessary for the breakdown and absorption of meat (7).

Evolutionarily, the size of any animal’s digestive tract depends on two factors — their diet and gut microbes.

The more calorie-dense the diet (like that of any carnivore), the less time and microbial help needed for digestion and absorption — hence the shorter gut in carnivores (8).

Meanwhile, the diet of herbivores comprises plants, which aren’t calorie-dense.

Thus, herbivores need to eat larger quantities of these foods to meet their daily calorie needs, and their digestive systems have to work harder to extract nutrients — hence the longer gut in herbivores.

Being omnivores, humans are capable of eating and digesting both meat and plants, so the length of your gut falls somewhere in between (9, 10).

SUMMARY

Biologically, humans are capable of eating and digesting both meat and plants, though our bodies can’t digest certain plant parts.

Plants don’t provide certain nutrients that animal products do.

One such essential nutrient that you can’t get from plants is vitamin B12, which is necessary for the normal function of the nervous system and the formation of red blood cells (11, 12).

This is why people who follow a diet that excludes all animal products are advised to take vitamin B12 supplements.

Other nutrients, such as creatine, vitamin D3, and omega-3 fatty acids like docosahexaenoic acid (DHA), are also missing in a plant-based diet. Yet, your body can produce them in small amounts, so you don’t need to rely solely on your diet to obtain them (13).

However, this bodily process isn’t very efficient. Plus, studies reveal that vegans and vegetarians have lower blood levels of omega-3s like eicosapentaenoic acid (EPA) and DHA — so omega-3 supplements made from algae are usually recommended (14, 15, 16, 17).

Plus, meat isn’t the only source of creatine or vitamins B12 and D3. Lacto-vegetarian diets that include dairy, ovo-vegetarian diets that include eggs, and pescatarian diets that include fish also provide these nutrients.

All the same, vegetarians and vegans may not get enough iron in their diets, as plant foods only offer this mineral in small amounts (18, 19, 20).

Keep in mind that vegan and vegetarian diets should be properly planned to avoid nutrient deficiencies. Other nutrients that may be difficult to obtain on such diets include protein, iodine, zinc, and calcium (21, 22, 23, 24).

Health effects of omnivorous vs. plant-based diets

It’s important to remember that there are downsides to eating certain kinds of meats.

Processed meats may be associated with a slightly increased risk of colorectal cancer — though other factors may also be at play — and too much meat intake is tied to an increased risk of death by any cause (25, 26, 27, 28).

On the other hand, vegetarian and vegan diets have consistently been shown to protect against heart disease. They may also help safeguard against cancer, though current research is mixed (29, 30, 31, 32).

While you can get all the nutrients you need on plant-based diets, proper meal planning and supplementing are essential (33).

SUMMARY

Even though meats provide certain nutrients that plants don’t, eating meat isn’t necessary for your health or survival. With appropriate planning and supplements, plant-based diets can provide the nutrients your body needs.

The foods and dishes that are passed down to you by your community, family, and ancestors are often called cultural foods.

Meat is an integral part of many food cultures around the world.

Whether a particular culture eats certain foods is informed by conditions like their surroundings, religious beliefs, and local plant and animal life.

It’s only natural that people bond over food. If meat is an integral part of your culture, it may become a central part of your identity, too.

Understanding the practices and traditions of your greater food culture may feel important for you to thrive, eat well, and connect to your roots — and these are perfectly valid reasons to either eat or avoid certain foods (34).

SUMMARY

Eating or not eating meat is a vital aspect of some cultures. Consequentially, following cultural norms surrounding dietary practices can be very important for some people.

Healthy adults are fully capable of eating and digesting meat. Still, nutritionally and biologically, you can live without it.

That said, humans are social animals whose beliefs about eating meat also depend on their cultural and religious norms.

If you’re curious about whether you should eat meat, know that there’s no right or wrong answer. You may be compelled by arguments in favor of vegan or vegetarian diets — or you may want to learn to cook meat dishes that your parents made for you growing up.

Ultimately, whether you eat meat is an individual choice.