Researchers studied the bones of 154 people who lived along the San Francisco Bay thousands of years ago to figure out what they ate. By analyzing special chemicals in the bones called isotopes, scientists discovered that different groups living at different locations along the bay ate different foods based on what was available near them. Men and women ate slightly different diets, but the types of food people ate stayed pretty much the same over 2,300 years. This research helps us understand how Native American communities, specifically the Ohlone people, managed their food sources and lived successfully in the Bay Area for centuries.

The Quick Take

  • What they studied: What did people who lived around San Francisco Bay 2,500 years ago eat, and did their diet change over time or differ between locations?
  • Who participated: 146 people (from 154 burials) who lived at one main site and nearby areas along the eastern shore of San Francisco Bay between 2,500 and 180 years ago. The research was done with the Muwekma Ohlone Tribe, the descendants of these ancient people.
  • Key finding: People living at different locations along the bay ate different foods based on what plants and animals were available nearby. Men ate slightly more seafood than women, but overall, people’s diets stayed similar for over 2,000 years. Each local group had its own food sources and didn’t rely on distant areas.
  • What it means for you: This research shows how Native American communities were skilled at using local resources and adapting to their specific environments. It helps us appreciate the sophisticated knowledge these groups had about their land. However, this is historical research about ancient populations, so it doesn’t directly apply to modern nutrition choices.

The Research Details

Scientists examined bones from people buried at an archaeological site called CA-ALA-329 and compared them to bones from four other nearby sites. They looked for two special chemicals in the bones—carbon and nitrogen isotopes—which act like fingerprints showing what foods people ate. Different foods leave different chemical signatures in bones, so by measuring these signatures, researchers can figure out whether people ate more plants or animals, and whether they ate ocean food or land food.

The researchers analyzed two different parts of the bones: collagen (the protein part) and bioapatite (the mineral part). Both parts preserve information about diet, but they can show slightly different things. This double-checking method helps make sure the results are accurate. The team looked at whether diet changed over time (from 2,500 to 180 years ago) and whether it differed between men and women or between different locations along the bay.

This approach is important because it lets scientists learn about ancient diets without relying only on leftover food remains, which can be incomplete or damaged. The isotope method works like a time machine for food—it shows what people actually ate and absorbed into their bodies, not just what trash they left behind. By comparing multiple sites across the bay, researchers could see if geography affected what people ate, which tells us about how different communities controlled and used their local resources.

This study is reliable because it examined a large number of people (146 individuals) from a well-preserved archaeological site. The researchers used two different methods to check their results and compared their findings to other sites in the region. The study was done in partnership with the Muwekma Ohlone Tribe, which is important because it respects the descendants of these ancient people and ensures the research is culturally appropriate. The main limitation is that isotope analysis shows general diet patterns but can’t tell us about specific individual meals or seasonal changes in eating habits.

What the Results Show

The chemical analysis showed that people living along the eastern shore of San Francisco Bay ate a mix of ocean foods (like fish and shellfish) and land foods (like plants and land animals). On average, the isotope values suggested a diet that included significant amounts of seafood, which makes sense given their location near the bay.

Interestingly, the researchers found no major changes in diet over the 2,300-year period they studied. This suggests that people found a successful way of eating and stuck with it—they didn’t need to dramatically change their food sources even as their population grew and they became more settled in one place.

When comparing different locations along the bay, the researchers discovered that diet varied based on latitude (how far north or south you were). This suggests that each local group ate foods that were available in their specific area rather than trading for food from distant places. This pattern shows that different Ohlone communities were self-sufficient and specialized in using their own local resources.

Adult males had slightly higher isotope values than adult females (less than 1.1‰ difference), suggesting men may have eaten somewhat more seafood or different types of seafood than women. However, this difference was small, indicating that men and women ate fairly similar diets overall. The researchers also found that the two different bone analysis methods (collagen and bioapatite) gave consistent results, which strengthens confidence in the findings.

This research fits with existing theories about how hunter-gatherer societies work. Scientists had predicted that as populations grew and people stayed in one place longer, they would need to eat a wider variety of foods and become less efficient at hunting and gathering. However, this study suggests that the Ohlone people may have adapted differently—they maintained stable diets over centuries by carefully managing their local resources and territories rather than constantly searching for new food sources.

The isotope method shows general patterns but can’t tell us about specific foods or seasonal eating habits. The study focuses on one main site with some comparison to nearby sites, so it may not represent all Ohlone communities around the bay. Additionally, isotope values can be affected by factors like age and health status, which weren’t fully accounted for. The research also can’t determine whether the slight differences between men and women reflect different food choices or different amounts of the same foods.

The Bottom Line

This research doesn’t provide direct recommendations for modern eating habits. Instead, it offers historical and cultural insights into how Native American communities successfully managed their food resources for thousands of years. If you’re interested in sustainable eating or local food systems, this research illustrates the value of understanding and using what’s available in your specific region.

This research is most relevant to people interested in Native American history, archaeology, and how indigenous communities lived sustainably. It’s particularly important for the Muwekma Ohlone Tribe and other Bay Area communities learning about their ancestors. Educators, students, and anyone curious about Bay Area history will find this valuable. This is not medical or nutritional advice, so it shouldn’t influence personal dietary choices.

This is historical research about events that occurred 180 to 2,500 years ago, so there is no timeline for modern applications. The research helps us understand the past, not predict the future.

Want to Apply This Research?

  • While this ancient research doesn’t apply to modern nutrition tracking, users interested in sustainable eating could track their use of local, seasonal foods from their region and compare it to how much they rely on distant food sources—similar to how the Ohlone people used local resources.
  • Consider learning about foods native to your region and trying to incorporate more locally-sourced options into your diet. This honors the sustainable practices of indigenous communities and can support local farmers and ecosystems.
  • Track the percentage of your meals that use local or regional ingredients versus imported foods. Over time, see if you can increase your reliance on local food sources, mirroring the resource management strategies that made the Ohlone communities successful.

This research is historical and archaeological in nature, examining the diet of people who lived 180 to 2,500 years ago. It does not provide medical, nutritional, or dietary advice for modern individuals. The findings are specific to ancient Bay Area populations and should not be used to make decisions about your personal diet or health. If you have questions about your nutrition or diet, please consult with a qualified healthcare provider or registered dietitian. This research is presented for educational and cultural understanding purposes.