In modern times, the relationship between humans and meat-eating is a topic that splits opinions and causes much debate.
On the one hand, many people think of meat as an ‘ancestral food’ that’s good, or even essential, for us.
On the other, some people believe we should reduce our meat intake, whether for ethical, climate, or health reasons.
In this article, we examine the question: ‘do humans need to eat meat?’
We’ll answer this question based on facts rather than fiction and using scientific evidence rather than opinion.
A History of Meat Consumption
Before we look at whether humans require meat in their diet, let’s first take a brief look at the history of human meat consumption.
Did Our Ancestors Eat Meat?
Firstly, we can often hear terms thrown around like ‘ancestral diet,’ but ancient humans likely ate a wide variety of diets. These diets varied depending on location, season, and even time period. In other words, an ‘ancestral diet’ in a tropical location would have looked rather different from one during a cold winter in an ice age.
That said, meat did play a key role in historical human diets, and it is thought that humans have been eating meat for millions of years. Evidence shows that early humans from the genus Homo began hunting and gathering approximately 2.5 million years ago (1, 2, 3).
It is widely accepted that this move to a diet featuring more meat had a significant impact on human evolution. For one thing, it provided an important source of energy, which was important for survival in times of food scarcity. It also would have raised protein intake, thus increasing muscle protein synthesis; the resulting greater muscle mass would also have had advantages for hunter-gatherers (4).
Furthermore, it is widely thought that meat may have played a role in human brain development due to the nutrient and energy-rich animal foods humans began consuming (5).
Around 500,000 years after humans started eating meat (2 million years ago), human brain volume had expanded from 600 cm³ to 850 cm³ before increasing to 1000 cm³ somewhere between 1.5 to 1.8 million years ago (6).
By 200,000 years ago and the appearance of modern homo sapiens, brain size had reached 1350 cm³ (7).
However, it is worth noting that there are competing theories to meat intake fuelling brain size development, which is not settled science. Other theories include increased energy intake from the advent of cooking, the ability to eat (cook) starches, genetic mutations, and environmental factors (8, 9, 10, 11, 12).
In more recent times, we also have good evidence showing:
- Meat intake played a role in the diets of ancient Eastern African herder groups approximately 5000 years ago (13)
- Çatalhöyük, Southern Anatolia (modern-day Turkey), was arguably the first city-like civilization. Analysis of fats and nutrients absorbed by Çatalhöyük pottery demonstrates that meat products played a significant role in their diet 8,000 years ago (14).
- Over the last 4,000 years, meat intake progressively grew in Central Germany as farming subsistence grew (15).
- Humans have consumed meat from reptiles for at least 10,000 years (16).
What We Can (and Cannot) Learn From Ancestral Diets
Since we discussed humanity’s history of meat-eating, it is important to note what we can (and cannot) infer from this.
Firstly, meat provides a range of essential nutrients, and it was (and is) a valuable energy source. This energy provision would have been even more important in times of famine when food was scarce.
However, it tells us very little about the following points:
- Exactly how much meat our ancestors ate, and as part of what dietary system
- The health effects of meat
- If a high meat intake is compatible with longevity
- Do we need to eat meat?
This website has covered some of the benefits and downsides of red meat before, so we will solely focus on the last question: do we need to eat meat?
To do this, we’ll first look at what nutrients meat provides.
What Nutrients Does Meat Provide?
There are numerous types of meat, and the exact nutrient profile will vary depending on the variety.
However, generally speaking, meat provides the following nutrients in moderate to high amounts (17, 18):
- Protein: typically 12-35% by weight, depending on meat variety, and a rich source of all amino eight essential amino acids
- Fat: ranges from around 1% (chicken breast) to >30% (pork chop)
- Iron: red meat contains a good source of heme iron, a highly bioavailable form of the mineral
- Vitamin B12 and other B vitamins
In addition to its vitamin and mineral content, meat can also provide several other nutrients thought to have benefits (19):
- Anserine: a dipeptide found in meat that has antioxidant properties (20).
- Carnosine: a dipeptide that may help to protect against free radical damage and oxidative stress (21).
- Creatine: an amino acid with importance for energy storage. We can find it preformed in fish and meat, and the body can make it from the amino acids arginine, glycine, and methionine (22).
- Taurine: an amino acid found preformed in fish and meat that can also be derived from the amino acid cysteine. It has antioxidant properties and plays a role in energy metabolism (23, 24).
- 4-hydroxyproline: an amino acid predominantly found in animal proteins that may benefit skin and bone health (25, 26).
Do Humans Need To Eat Meat?
To put it simply: meat is not essential, but many of the nutrients meat contains are.
Providing these nutrients are obtained in sufficient quantities from elsewhere, there is no specific need to eat meat. However, it is worth noting that research has found that meat greatly contributes to typical nutrient status in the United States.
For example, a 2013 multiethnic cohort study analyzed the diets of 215,000 men and women aged between 45 and 75. These participants were of five ethnicities: African American, Latino, Japanese American, Native Hawaiian, and Caucasian. The study aimed to investigate the contribution of meat to total iron, vitamin B12, and zinc intake. Results demonstrated that, across these ethnic populations, the contribution of meat to total intake was (27):
- Iron: 4.3 – 14.2%
- Vitamin B12: 19.7 – 40%
- Zinc: 11.1: – 29.3%
Furthermore, iron and zinc micronutrient deficiencies are prevalent globally, demonstrating that care is necessary if replacing food that provides these nutrients (28).
Thus, while it isn’t necessary to eat meat, it is important to know what nutrients it provides and where else to obtain them if not eating it.
For individuals who consume seafood and dairy, it is relatively simple to obtain nutrients such as vitamin B12 and zinc, and many plant foods are good sources of iron. However, it becomes progressively harder for vegetarians and vegans to obtain these nutrients, and these diets should be well-researched to allow appropriate formulation.
How to get every vitamin and mineral on a vegan diet
With vegan diets, plant foods do not contain vitamin B12, so fortified foods or a B12 supplement are necessary. Taking a B12 supplement is the most reliable way of ensuring sufficient B12 intake (28, 29).
What Happens If Humans Don’t Eat Meat?
If a meat eater stops eating meat, there will be no sudden apparent changes.
Over time, they may either progress with a health-promoting diet, or they could potentially develop nutrient deficiencies (30). This would entirely depend on the new diet and whether it is well-formulated to ensure a sufficient intake of essential nutrients.
In the longer-term, large observational studies with millions of person-years of follow-up have compared the health outcomes of vegetarians and non-vegetarians. These studies mostly found a lack of significant differences in all-cause mortality between vegetarians and non-vegetarians (30, 31, 32, 33, 34).
This article shows that humans don’t need to eat meat. No foods are essential, but many nutrients are.
Meat can provide many of these nutrients in a convenient package, but we can also obtain them from elsewhere. This is relatively straightforward for dietary patterns that include dairy and seafood but requires more careful planning for vegetarian and vegan diets.
Lastly, while eating meat isn’t necessary, that doesn’t mean we shouldn’t eat it. Whether one chooses to eat meat or not depends on the individual, their ethical beliefs, and their interpretation of the nutritional benefits and downsides of meat.