How do archaeologists reconstruct past human diets?

Stable isotopes and bone chemistry

Archaeologists reconstruct past diets by combining chemical, microscopic, and contextual evidence so that what people ate can be inferred from preserved tissues and artifacts. One primary technique uses stable isotope analysis of bone collagen and tooth enamel. Carbon isotopes distinguish consumption of C3 plants such as wheat and rice from C4 plants such as maize and millet, while nitrogen isotopes track trophic level and marine versus terrestrial protein intake. Robert A. Schoeninger at the University of Arizona helped establish how bone chemistry records long-term dietary signals, allowing researchers to compare individuals, communities, and changes through time. Isotope data are especially powerful when paired with chronological control from radiocarbon dating and local ecological baselines, because plant ecology and local food webs influence isotope values.

Microscopic and molecular traces

Microscopic remains trapped in dental calculus and pottery residues provide direct evidence of plant and animal foods. Dental calculus can contain starch grains and phytoliths that identify particular cereals, tubers, and wild plants, and proteomic analysis of calculus can reveal species-specific proteins. Christina Warinner at Harvard Medical School has been central to developing ancient dental calculus proteomics, demonstrating how oral deposits preserve dietary and microbial biomolecules. Organic residue analysis of ceramics recovers lipids and biomarkers; Richard Evershed at the University of Bristol pioneered methods to distinguish ruminant fats, dairy products, and aquatic resources, making it possible to detect cooking and storage practices that written records omit.

Contextual and comparative approaches

Zooarchaeology and archaeobotany place chemical and microscopic data into cultural and environmental context. Identification of animal bones and plant macrofossils from archaeological layers shows which species were available, domesticated, or exploited seasonally. Coprolites, preserved human feces, can contain undigested plant fragments, parasite eggs, and ancient DNA that inform on both diet and health. Ancient DNA studies of food species and human remains, used carefully alongside isotopes and residues, trace introductions of crops and livestock across territories; Greger Larson at the University of Oxford has led work on how domestication and animal management shaped human diets over millennia.

Relevance, causes, and consequences

Reconstructing diet explains economic choices, social inequality, and environmental impact. Shifts to agriculture or intensive pastoralism, detectable through rising C4 plant signals or increased dairy residues, often reflect climatic pressures, population growth, or cultural preferences. Those shifts carry consequences: rising carbohydrate consumption correlates with increased dental caries and enamel hypoplasia, evidence of nutritional stress; differential access to high-status foods appears in isotope and residue differences between burials, revealing social stratification. Territorial expansion and trade alter diets by introducing new crops and culinary techniques, transforming landscapes through deforestation and irrigation. Understanding past diets therefore illuminates human adaptation and the cultural meanings of food, linking biochemical signatures to lived experience and the shaping of environments.