Are we biologically designed to be frugivores?

The frugivore diet, also known as the fruitarian diet, mainly consists of fruit and raw vegetables, and has been gaining popularity recently. Although eating meat is the norm in almost every culture and region, some people believe humans are biologically designed to be frugivores.

Many vegans strongly claim this belief; there are entire online communities dedicated to the expansion of veganism and promotion of the frugivore lifestyle. However, a 2021 study by Statistica revealed that 86% of the world’s population incorporates meat into their diet.^[]

Other animals eat what is advantageous to their genetic makeup, so are we truly meant to be frugivores if our species eats so much meat?

Why we may be frugivores

There are three major different dietary categories: carnivores (who strictly eat meat), herbivores (who strictly eat plants), and omnivores (who eat plants and animals). Frugivores, a subcategory of herbivores, primarily thrive on fruit-like produce like roots, shoots, or nuts.

It is important to note the term “primarily,” as frugivores have a preference for fruit but may also consume seeds, nuts, and leaves. For example, chimpanzees are frugivores, eating about 50% fruit, also known as “flexible omnivores.”^[]

A study published in Human Evolution noted that humans consume meat not because it’s physiologically optimal, but because it’s habitual—something done out of necessity at one point for our ancestors that has remained in our diet for generations.^[] The researchers compared gut measurements from humans and other primates to those of carnivores and found that the human digestive tract is not specialized for meat-eating.

This study posits that our omnivorous behavior may have been caused by a shift in food resources during our evolutionary process; a climate crisis in the late Miocene period likely altered nutrient availability for hominids, early predecessors of neanderthals. Thus, it can be inferred that the interjection of meat into the human diet was not because we were designed to consume it; rather, it happened out of necessity.

But what about our canine teeth? Humans share their sharp incisors with carnivores like lions and wolves. But as the authors of an Insider article wrote, “Contrary to popular belief, human canines are not for tearing and ripping meat. Instead, our ancestors used them to fight male rivals for mating rights.”^[]

Since we no longer fight with our teeth, our canines now serve as an aid to tear through fibrous or hard-to-digest food. However, the misconception regarding their ancestral purpose may be why meat has remained a heavy staple in most of our diets.

Additionally, we have ptyalin in our saliva, which is a type of amylase, an enzyme used to digest starches—but omnivores and carnivores don’t have this in their saliva.^[]

Is being a frugivore healthy?

This raises questions on what we should be eating, and what nutritionists should recommend to patients.

The health benefits of fruits and vegetables are indisputable. However, it’s easy to underestimate just how crucial they are to our health—especially since the food pyramid also prioritizes grains, dairy, and meat.

According to the American Society for Nutrition, suboptimal fruit consumption caused nearly 1.3 million deaths from stroke and more than 520,000 deaths from coronary heart disease in 2010. Those who eat fruit regularly (and in bulk) are less likely to be obese and have a decreased chance of developing obesity related disorders.

Fruit has also been linked to reduced blood pressure and cholesterol levels. Fruits high in antioxidants such as blueberries, blackberries, raspberries, strawberries, and apples may reduce your cancer risk. The fiber in fruit, found mainly in its skin, suppresses your appetite, helping to prevent overeating and weight gain.

A study published in Nutrition Journal found that restricting fruit intake was not beneficial in patients with type 2 diabetes.^[] This was significant, since many people with type 2 diabetes must monitor their sugar intake to keep their insulin balanced. This mainly has to do with the metabolism of natural vs refined sugar.

But can we still get all the nutrients we need from strictly eating fruit? A 2021 study published in Current Developments in Nutrition found that humans may actually benefit from a meat-heavy diet.^[]

Scientists tracked the health of 2,029 people (all ranging in age) on a carnivorous diet.

However, cardiovascular disease risk factors were variably affected, including an increase in lipids and LDL cholesterol levels.

Most study participants reported improvements in their chronic medical conditions as well as their general health; energy, strength, sleep, memory, focus, and mental clarity all improved on a meat-based diet. This flies in the face of research suggesting enhancements in all of these categories on a diet that’s heavy in fruit.

It’s important to note that vitamin B12 is almost exclusively found in animal products such as fish, meat, dairy, and eggs and is an essential nutrient. It's therefore recommended that vegans—including frugivores—supplement their diets with a B12 vitamin supplement.

Individual preference

The information from these conflicting studies obscures the physiological evidence that suggests we’re not solely meat eaters. Even so, the health benefits of fruit are undeniable, and should not be restricted when prompting or following a well-balanced diet program.

Those with underlying health issues or dietary restrictions like allergies, irritable bowel syndrome (IBS), or certain nutrient deficiencies may require larger or smaller amounts of fruit, meat, or other staples from the food pyramid in their diet.

For example, patients with digestive tract issues or IBS may want to avoid red meat and consume easy-to-digest proteins like chicken, turkey, and fish and eat fruit sparingly. Other undesirable medical symptoms and disorders may be alleviated by different amounts and types of these foods.^[]