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Between 2013 and 2014, 19 people were voluntarily locked in a clinic for days at a time—not once, but on four separate occasions. They were fed a different, strict diet on each of their three-day-long visits, and were forbidden to exercise. Computer access and visitation were allowed, so long as guests didn’t smuggle in snacks. Subjects turned over all their urine, from morning, afternoon, and night, to researchers.
These participants temporarily sacrificed their freedom to help dietician Gary Frost and colleagues at Imperial College London understand how eating habits influence the relative concentrations of metabolites excreted in urine, and thus how urine could serve as an indicator of a person’s diet, which in the team’s experiment ranged from healthy to gluttonous. Frost’s team anticipated that such metabolomics analyses would provide more-reliable data for nutritionists than the traditional tactic of asking free-roaming subjects what they’ve been ...
