gladwell dot com / The Pima Paradox: "Unfortunately, the year after that original edition of Atkins' book came out, the American Medical Association published a devastating critique of this theory, pointing out, among other things, that ketone losses in the urine and the breath rarely exceed a hundred calories a day--a quantity, the A.M.A. pointed out, 'that could not possibly account for the dramatic results claimed for such diets.' In 'Dr. Atkins' New Diet Revolution,' not surprisingly, he's become rather vague on the subject, mysteriously invoking something he calls Fat Mobilizing Substance. Last year, when I interviewed him, he offered a new hypothesis: that ketosis takes more energy than conventional food metabolism does, and that it is 'a much less efficient pathway to burn up your calories via stored fat than it is via glucose.' But he didn't want to be pinned down. 'Nobody has really been able to work out that mechanism as well as I would have liked,'he conceded."