Science Update, the 60-second AAAS radio program, talked with human diet expert Peter Ungar and came away with a provocative conclusion: "If you think the modern American diet is bad for us," says host Bob Hirshon, "it might give you comfort to know that humans have been making unhealthful food choices since long before the advent of fast-food joints."

Ungar, a researcher at the University of Arkansas at Fayetteville, sees a relatively simple problem: We don't eat today what our distant ancestors evolved to eat. The research is interesting, but the implications are troubling for human health.

Listen to Science Update's first report from the AAAS Annual Meeting in Chicago.