Red meat fueled human evolution, but now it may be doing harm. Photo: Open sources
While red meat may have contributed to the shaping of the human species, our current craving for it is increasingly detrimental to both human health and the planet.
An interdisciplinary review published in The Quarterly Review of Biology examines how red meat shifted from a valuable source of concentrated nutrients to a factor contributing to chronic disease and environmental damage. Juston Jaceau, Kalyan Banda, Ajit Varki, and Pascal Gagneux combined data on hominin diets spanning roughly three million years with evidence from archaeology, epidemiology, and molecular biology.
The authors’ main argument is not that meat was inherently harmful or that humans were never adapted to consume it. Instead, they emphasize the drastic changes in its availability, composition, production, and cultural role. The sporadic consumption of animal tissues as part of our ancestors’ diverse diet bears little resemblance to the large portions and processed products common in many modern societies.
In the recent article, the researchers trace meat consumption back to the emergence of the genus Homo. Archaeological evidence suggests that early hominins incorporated animal-based foods into their diets, even though plant-based foods remained dominant.
The prized parts of the carcass likely differed from the steaks and roasts valued today. Fat, bone marrow, organs, and brain tissue probably offered greater nutritional value than muscle meat, as they provided more calories and essential lipids. These nutrients may have been particularly crucial for supporting the energy-intensive development of the infant brain. “The cultural significance of red meat in the modern Euro-American diet—typically centered on steaks and roasts—reflects ideals and biases that influence perceptions of early hominin diets,” the authors write. In other words, modern preferences may skew attempts to reconstruct what our ancestors actually sought out and consumed.
The review also challenges the common claim that meat consumption itself drove the expansion of the human brain. Protein is not particularly energy-dense, nor is it the brain’s preferred fuel source. Human success was likely linked to the ability to utilize a wide range of foods—including plants, fat-rich animal tissues, and other resources—that varied according to the season and environment.
This flexibility became especially valuable as early humans spread into unfamiliar habitats. Rather than relying on a single “ideal” diet, hominins survived by adapting their food intake to local conditions. This adaptability—rather than a universal, meat-centric menu—may be one of the most important lessons of human nutritional evolution.
Around 10,000 to 12,000 years ago, the advent of agriculture brought about significant dietary changes. While farming provided more reliable food sources and supported population growth, it also replaced a varied diet with a narrower reliance on staple cereal crops. This loss of dietary diversity contributed to nutrient deficiencies—such as iron deficiency—because grain-heavy diets provided less bioavailable iron. Such deficiencies were relatively rare among hunter-gatherers.
Today, for much of the world, meat is no longer merely an occasional source of nutrients. It has become the foundation of a global industry valued at $1.3 trillion, with further growth expected, particularly in low- and middle-income countries. Industrial production has made red meat available at a frequency and scale unprecedented in human evolutionary history.
Large-scale epidemiological studies consistently link high consumption of red and processed meat to an increased risk of cardiovascular disease, type 2 diabetes, colorectal cancer, and all-cause mortality. The International Agency for Research on Cancer classifies processed meat as a Group 1 carcinogen, meaning there is sufficient evidence that it can cause cancer in humans. Unprocessed red meat is classified as probably carcinogenic.
The review also examines a lesser-known biological explanation for some of these associations. The authors call this “xenosialitis”—a diet-induced inflammatory response involving N-glycolylneuraminic acid (Neu5Gc). Humans lost the ability to synthesize this sugar molecule approximately two million years ago, yet it remains is found in significant quantities in widely consumed red meat.
After red meat is consumed, Neu5Gc can enter human tissues. Because the immune system recognizes this molecule as foreign, antibodies may repeatedly attack cells containing it. The resulting chronic, low-grade inflammation can contribute to the development of atherosclerosis, accelerate the progression of colorectal cancer, and potentially lead to cognitive impairment.
The debate over health impacts is only one part of the argument. Industrial livestock farming generates approximately 15 percent of global greenhouse gas emissions and also leads to deforestation and water pollution. The intensive use of antibiotics in livestock farming can further contribute to the emergence and spread of drug-resistant bacteria.
The authors do not argue that everyone should completely eliminate red meat from their diet. Their broader point is that evolutionary history cannot serve as a simple justification for modern consumption. A food product can be valuable when it is scarce, nutritionally strategic, and part of a varied diet, yet become harmful when industrially produced and consumed in large quantities.
“The nature, scale, and context of red meat consumption today differ radically from those of our evolutionary past,” the authors conclude. The dietary flexibility that once helped humans thrive may now pave the way forward, allowing societies to rely less on red meat without pretending it played no role in humanity’s past.
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