Should We Eat Meat

Why has meat become both indispensable and controversial? Vaclav Smil’s comprehensive exploration of meat’s role in human civilization traces its evolutionary origins, cultural transformations, nutritional importance and environmental burdens. For Smil, meat is more than food — it is a mirror of our species’ development, ingenuity, and ethical complexity.

Evolutionary roots and biological dependence

Smil begins by showing how meat entered human evolution. Early hominins scavenged and hunted millions of years ago, and the introduction of cooking transformed energy use and anatomy. High-density animal protein enabled smaller guts and larger brains — the expensive-tissue hypothesis first articulated by Aiello and Wheeler (1995) gains new meaning here. Meat catalyzed cooperation, social bonds and technological innovation, cementing its biological importance in the human story.

Stable isotopic evidence from Paleolithic skeletons confirms heavy reliance on animal protein for some populations, while others diversified diets with fish and plants. Meat, then, became a flexible but powerful strategy in human adaptability — not merely a taste choice.

Nutritional function and health trade-offs

Smil carefully distinguishes meat’s nutritional value from its health risks. It supplies complete, highly digestible proteins (PDCAAS ~0.92 for beef), micronutrients like heme iron, zinc and vitamin B12, all fundamental for growth, cognition and metabolism. Yet when consumed excessively or in processed forms, meat contributes to cardiovascular disease and cancer risks. He quotes meta-analyses confirming processed meats’ strong correlation with mortality compared to lean or unprocessed cuts.

The sensible solution according to Smil is not abstinence but moderation. Lean, fresh meats and balanced diets outperform extreme avoidance or indulgence. Animal protein still prevents stunting and deficiency in vulnerable populations; meat’s qualitative role is as crucial as its quantitative intake.

Industrialization and global consumption

Modern societies transformed meat through technology: mechanization, nitrogen fertilizer, refrigeration and international trade created mass production systems. Meat shifted from luxury to staple. Smil describes Japan’s jump from 2 kg per capita in 1939 to 45 kg by 2000 and China’s massive post-1980s increase — emblematic of how economic growth brings meat abundance.

Fast food globalized taste, spreading standardized foods such as hamburgers and fried chicken. Brands like McDonald’s and KFC became symbols of dietary transition and cultural homogenization. Chicken, efficient and cheap, now leads global consumption growth, reflecting economic rationality but raising environmental and ethical questions.

Environmental and ethical reckoning

Smil does not avoid the costs: massive land use, deforestation, water consumption, greenhouse gases and animal welfare abuses. Livestock occupy roughly a quarter of Earth’s ice-free land and dominate terrestrial biomass. Feed crops (corn, soy) absorb vast energy and water resources, while intensive systems concentrate waste and pollution.

Ethically, CAFOs and broiler densification raise moral alarms. Animal suffering is a design choice, not necessity. Yet Smil insists on pragmatism — he sees full global veganism as unlikely, instead advocating rational meat consumption (15–30 kg per person annually) alongside improved welfare, substitution with dairy, eggs and aquaculture, and technological innovation like cultured meats.

Core message

“Meat has fed our evolution, shaped our economies and tested our ethics. We can neither wholly reject nor wholly embrace it — only rationalize how we produce and consume it.”

Through historical evidence, data and practical realism, Smil’s book becomes a manifesto for balance — sustaining human nutrition while tempering excess. This journey from prehistoric hunters to industrial consumers reveals how a biological necessity evolved into a planetary challenge requiring informed moderation.

Smil connects the distant roots of human carnivory with the industrial machinery that supplies contemporary diets. Understanding this continuum helps you see meat neither as primitive indulgence nor modern vice, but as a technological trajectory.

Early human carnivory

Fossil evidence such as Koobi Fora’s butchered bones (~1.95 million years ago) shows how Homo species shifted from plant scavengers toward sophisticated hunters. Cooking amplified caloric availability, enabling brain enlargement. Cooperative hunting fostered social complexity — food sharing laid groundwork for empathy and structure within early communities. Meat, in this sense, was a driver of civilization itself.

Domestication and mixed farming

Around 10,000 years ago domestication of goats, sheep, pigs and cattle expanded protein supply beyond hunting. Animals contributed power, manure and traction — functions far more versatile than meat alone. Mixed farming (livestock plus crops) allowed nutrient recycling, forming the enduring agricultural backbone of pre-industrial societies.

Industrial escalation: CAFOs and global meat markets

Post-1950 mechanization and compound feeds revolutionized meat supply chains. Systems like US feedlot finishing (cow–calf, stocker, finishing phases) exemplify greater efficiency but immense scale. Five Rivers Cattle Feeding once managed 820,000 heads at a time; poultry and pork integration confined animals to near-body-sized areas. This structure enabled cheap meat for billions but magnified waste, disease and welfare issues.

Historical arc insight

Humanity’s meat pathway evolved from ecological participation to industrial extraction — from hunting coevolved species to manufacturing their flesh.

Smil’s continuity view reveals industrialization as both success and pathology: astounding production efficiency paired with moral and ecological cost. The same scientific mastery that freed humans from hunger now challenges them to rethink animal use responsibly.

Meat’s nutritional appeal lies in its concentration of high-quality proteins and essential micronutrients, yet its health hazards stem from excess, composition and processing. Smil teaches you to read this balance scientifically rather than ideologically.

Protein quality and micronutrients

Animal protein delivers complete amino-acid profiles and superior digestibility compared with most plant proteins. Eggs and casein rank PDCAAS 1.0; beef averages 0.92. Iron, zinc and B12 occur in bioavailable forms critical for immunity and nerve function. Children particularly benefit — studies from Kenya and elsewhere show modest meat inclusion improves growth and cognition.

Health risks and epidemiological nuance

Problems emerge in patterns, not mere presence. Saturated fat and processed meats correlate with cardiovascular disease and cancer. Yet whole dietary context matters: Mediterranean nations consume moderate meat yet maintain lower chronic disease rates. Smil debunks oversimplified claims by urging readers to distinguish between correlation and causation in epidemiology.

Practical dietary moderation

Global health bodies recommend saturated fats under 10% of daily energy and cholesterol below 300 mg/day. Following these, lean meats easily fit balanced diets. The intelligent policy is moderation and diversity — pairing animal foods with plant sources instead of extremes. Smil’s message supports nutrition as a calibrated tool, not a moral battleground.

Key takeaway

Meat’s biological virtues outweigh its health risks at moderate intake. The real enemy is imbalance, not animal food itself.

Understanding these evidence-based contrasts prepares you to choose wisely: use meat as a dense source of essential nutrients but regulate portion, preparation and type. You gain both human health and ecological conscience.

Behind every steak or drumstick lies an extensive feed economy powered by corn and soy. Smil dissects this invisible infrastructure to reveal how resource flows translate into environmental footprints and efficiency differences among species.

Feed composition and industrial dominance

Modern compound feeds integrate cereals, oil meals and micronutrient premixes. Corn provides ~14.3 MJ/kg energy, soy meal supplies ~42–44% protein. By 2010 global compound-feed output exceeded 720 million tonnes, dominated by the US, EU, China and Brazil. Soybean expansion in Brazil (0.25 Mt in 1960 to 69 Mt in 2010) mirrors the feed revolution’s scale. Multinationals like Cargill and Purina orchestrate this trade, linking feedstocks to livestock systems worldwide.

Conversion efficiencies and species contrast

Efficiency declines sharply across species. Producing one kilogram of edible meat requires roughly 3 kg feed for chicken, 9 for pork, and 25 for beef. Energy and protein conversion rates clarify the hierarchy: chicken converts feed energy with 15% efficiency and protein at ~30%, while beef averages below 4%. This hierarchy guides rational protein production — poultry and pork minimize competition with human-edible crops compared to grain-fed cattle.

Environmental leverage

Feed efficiency translates directly into climate and land-use leverage. Livestock collectively claim ~33% of arable land for feed. When feed is grain-based, fossil energy for fertilizer, transport and processing dominates emissions. Policies focusing on feed reform — shifting to crop residues, by-products, and forage — can reduce both greenhouse gases and nutrient losses without sacrificing protein supply.

Insight

Efficiency is the real sustainability variable — not abstinence or abundance, but how effectively we convert plant matter to animal protein.

Smil’s comparative data make species choice a practical lever for environmental and nutritional optimization. Poultry emerges not as moral virtue but as energetic prudence; beef remains premium but costly, inviting reform in feed composition and management.

Smil quantifies meat’s planetary impact, examining land, water, nutrients and greenhouse gases with nuance beyond headline soundbites. You learn that numbers fluctuate with chosen boundaries but trends remain unmistakable: livestock intensification strains ecosystems.

Land and biomass dominance

Pastures occupy ~3.4 billion hectares — a quarter of Earth’s ice-free area. Livestock zoomass soared from ~170 Mt in 1900 to ~600 Mt by 2000. Domesticated vertebrates now outweigh wild mammals by roughly 25:1. Overgrazing degrades 20–70% of pastures depending on region. These proportions illustrate meat’s overwhelming spatial footprint and biotic dominance.

Water and nutrient stress

Mekonnen & Hoekstra’s estimate of livestock water footprint (~2,422 km³/year) reveals consumption dominated by green (rainfall) water. Beef embodies 9,000–15,000 L per kilogram in global averages; chicken uses around 2,000. Manure from large feedlots amplifies nutrient leakage—one 50,000-head lot produces ~225,000 tonnes yearly. Responsible recycling back to cropland remains the key mitigation task.

Greenhouse gas debates and data caveats

FAO’s “Livestock’s Long Shadow” placed livestock at 18% of anthropogenic GHGs (7.1 Gt CO₂-equivalent), but Smil notes methodological caveats: varying emission factors, land-use assumptions and time horizons. Short-term methane potency implies ruminant improvements yield near-term climate benefits. He calls for regional precision instead of global generalizations.

Guiding principle

Quantification must inform moderation; uncertainty does not absolve responsibility. Local data, not global averages, drive effective solutions.

The environmental chapters emphasize contextual literacy: asking “how much?” demands asking “where, when and how produced?” Smil’s realism reframes environmentalism as an optimization problem — aligning production with ecosystem capacities rather than binary ideology.

Smil devotes attention to what enters and escapes meat systems — pathogens, antibiotics and microbial evolution. He treats safety not as panic but as management protocol across scales from farm to kitchen.

Pathogens and outbreaks

Historic diseases like trichinellosis and brucellosis have receded in developed nations but persist globally. Foodborne bacteria—E. coli O157:H7, Salmonella, and Campylobacter—cause millions of illnesses annually. Yet per-meal risks remain low; correct cooking and hygiene nearly eliminate them. Large epizootics such as BSE and foot-and-mouth disease illustrate systemic vulnerabilities with massive economic loss rather than direct human mortality.

Antibiotic use and resistance

Over 13,000 tonnes of antibiotics used in US livestock (2009) fostered resistant strains like MRSA CC398. Regulatory curbs emerged late—FDA restrictions in 2010–2012 marked the turn toward stewardship. The lesson is institutional: resistance arises from incentives for cheap growth rather than necessity.

Viral and prion concerns

BSE and avian influenza underscore cross-species contagion risks. Though rare, their global panic potential demands vigilance through feed control, containment and surveillance. Kitchen practices become the individual layer of systemic resilience.

Practical message

Safe meat depends on hygiene and policy intertwined: personal diligence plus systemic oversight reduce both daily and catastrophic risks.

Smil’s pragmatic tone transforms fear into competence—showing you that safety is achievable through informed regulation and consumer habits rather than blanket avoidance.

Smil’s concluding vision merges ethics, environment and nutrition into pragmatic reform. Instead of utopian veganism or unchecked industrialism, he outlines a feasible path toward humane, sustainable meat economies.

Welfare and reform

Current broiler and pig confinement exemplify preventable suffering. Minimal space (560–650 cm² per bird) and genetic modifications cause pain for profit. Smil advocates redesign—better lighting, slower growth strains, disease prevention over antibiotic crutches. Denmark proves productivity can rise even as antibiotic use falls 60%.

Substitution and innovation

Alternatives like tofu, mycoprotein (Quorn) and plant-based brands expand options though market shares remain <4%. Cultured meat promises radical change but faces scale and cost barriers. Pragmatic substitution—mixing plant proteins into processed meat or shifting to eggs and aquaculture—offers quicker, scalable impact.

A rational global scenario

Smil’s model projects sustainable production around 190–200 Mt per year combined with substitutes supplying 15–20% of current protein needs. His rational consumption range, 15–30 kg per person yearly, matches health and climate harmony exemplified by France and Japan.

Final vision

Human diets can remain omnivorous yet ecologically responsible—through welfare reform, moderation, and intelligent substitution.

Smil concludes with pragmatic optimism: meat has built civilization but must now evolve. Rational consumption is not deprivation but adaptation — preserving nutritional strength while curbing cruelty and waste.