Gulp: Adventures on the Alimentary Canal

Mary Roach opens her exploration of the human digestive system by recounting a 1968 experiment at UC Berkeley where six volunteers consumed meals made from bacteria for two days while confined in a metabolic chamber. NASA had commissioned this research to develop sustainable food sources for long-duration space missions to Mars, hoping to create meals from astronauts’ biological waste. The experiment failed spectacularly: Participants experienced severe digestive distress, and the bacterial food proved unpalatable and was described as slimy and metallic-tasting.

While acknowledging that this research seemed to ignore fundamental human psychology around food consumption, Roach defends the value of such unconventional scientific inquiry. She celebrates researchers who pursue questions that might be strange or uncomfortable, citing historical examples like William Beaumont’s stomach experiments and physicians who studied digestion using executed prisoners.

Roach argues that scientific literature about eating has been overshadowed by culinary writing, comparing how society romanticizes both food and sex while avoiding their biological realities. She contends that the human digestive system and the scientists who study it deserve just as much attention as gourmet cuisine does.

The author traces her fascination with human anatomy to a plastic educational torso in her fifth-grade classroom, which sparked her curiosity about the body’s internal workings.