What do people eat? Plant and animal DNA in sewage provide clues episode artwork

EPISODE · Aug 5, 2026 · 12 MIN

What do people eat? Plant and animal DNA in sewage provide clues

from Science Friday · host Lawrence David, Flora Lichtman, Charles Bergquist

Imagine you wanted to get a general idea of what people are eating in a given community. You could look at grocery store sales, or do surveys, but neither can capture a complete picture.  Microbiome researcher Lawrence David and his lab look to another source of data: genetic material in sewage water. It turns out that detectable DNA signatures of individual plant and animal species remain behind even after they’ve been eaten, digested, excreted, and flushed down the toilet. He joins Host Flora Lichtman to describe his “Edible Atlas” project, the backend limitations of sewage analysis, and where the research might go.  Guest:  Dr. Lawrence David is an associate professor of molecular genetics and microbiology in the Center for Genomics and Computational Biology. He runs the Edible Atlas project at Duke University. Other episodes you may enjoy: You Share Your Gut Microbiome With Your Friends Dirty Diapers Reveal How Germy Babies’ Microbiomes Are The transcript for this episode is available at sciencefriday.com. Subscribe to this podcast. Follow our show on Instagram, TikTok, Facebook, and Bluesky @scifri and sign up for our newsletters. Got a science question that’s keeping you up at night? Call us: 877-472-4374 Hosted by Simplecast, an AdsWizz company. See pcm.adswizz.com for information about our collection and use of personal data for advertising.

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DNA signatures of plant and animal species remain behind even after they’ve been eaten, digested, excreted, and flushed down the toilet.

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What do people eat? Plant and animal DNA in sewage provide clues

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