We Are What We Ate: The Diets That Fueled Human Evolution

The vast majority of human evolutionary history was fueled by diets composed exclusively of wild foods gathered and hunted rather than planted and raised. Compared to our ape-ancestors, and in contrast to today's living apes, members of the genus Homo have increasingly relied on technology and cumulative culture, such as use of complex tools, fire, and later fermentation, to access a broader range of foods across diverse ecosystems while defining foodways and regional identities. These innovations facilitated the global radiation of humans to every corner of the planet. Following the Last Glacial Maximum, approximately 12,000 years ago, the transition to agriculture marked a pivotal shift in human dietary patterns. The domestication of crops and livestock enabled food surplus, sedentism, and population growth, while introducing new nutritional and health consequences. More recently, widespread industrial food processing and ultra-refined diets may be driving additional physiological changes with unknown consequences for metabolism, disease, and the human microbiome, along with environmental impacts. This symposium examines the diets that fueled human evolution, drawing on evidence from paleontology, archeology, genetics, comparative anatomy and physiology, modern nutritional science, microbiome research, and ethnographic studies of the few remaining living foragers. Together, these perspectives can illuminate how dietary adaptations have shaped and continue to influence human biology, health, and culture.

Event Sessions:

Speakers	Session
Gerald Joyce Erica Sonnenburg	Welcome & Opening Remarks Welcome by CARTA Co-Director and Salk Institute President, Jerry Joyce. Opening remarks by Event Co-chair, Erica Sonnenburg
Matthew Sponheimer	The diets of early hominins
Jessica Thompson	The human predatory pattern Humans consume more meat than any other primate. We are also the only primate to regularly eat animals larger than ourselves. This is the human predatory pattern, but how, when, and why did this happen? What were the ecological and evolutionary circumstances that positioned our ancestors to become the first primate intruders into the carnivore guild? New fossil and archaeological discoveries dating between 4 – 2 million years ago continue to pull back the curtain on these questions, and new... read more
Nathaniel Dominy	From sugar to starch: Detecting diet shifts during human evolution
Ajit Varki	Red meat in anthropogeny: From a blessing to a curse? We humans are unusual in comparison to our primate cousins, regarding our penchant for consuming meat from large animals. Archaeological evidence of stone tools useful for butchery and cut marks on bone fossils indicate that this dietary shift predated the origin of the genus Homo about 2 million years ago.  Such foods are also rich in essential amino acids, certain vitamins like B12 (not made by plants) and trace elements. Iron is essential for almost all life forms, but it is also toxic in... read more
Rachel Carmody	The importance of cooked food
Justin Sonnenburg Erica Sonnenburg	Adaptation of the microbiome to changing diets The human gut houses trillions of microbes from hundreds of species forming an ecosystem called the microbiome. This ecosystem not only aids digestion and gut health, but is wired into diverse physiological processes including immune system regulation, metabolism, and central nervous system function. Unlike our human genome, our microbiome can adapt to changes in its environment on a timescale ranging from days to weeks with diet being one of the most powerful influences on the microbiome. This... read more
Erin Hecht	Fermentation and human brain expansion The expansion of the human brain represents a metabolic paradox: how did our ancestors fuel such an energetically expensive organ while reducing the size of the digestive tract? While the "Cooking Hypothesis" suggests fire was the primary driver, the transition likely began much earlier. This talk will explore the External Fermentation Hypothesis, proposing that the intentional or accidental fermentation of foods could have provided a crucial "external stomach." By outsourcing the work of... read more
Stefan Ruhl	Human evolution, spit by spit
Lora Iannotti	The diets of children past and present Greater than half of the world’s children are malnourished, experiencing micronutrient deficiencies, stunted growth and development, or overweight/obesity. If malnutrition occurs during the first 1,000 days of life, there will be life-long consequences. Many populations globally no longer have access to critical elements of evolutionary dietary patterns such as animal source foods or diet diversity giving rise to these problems. We describe the empirical evidence highlighting the disconnect in... read more
All Speakers Pascal Gagneux	Wrap-up, Question & Answer Session, and Closing Remarks Question and answer session with all speakers. Wrap-Up by symposium co-chair, Erica Sonnenburg. Closing remarks by CARTA Executive Co-Director, Pascal Gagneux.