Snake-oil and moralizing. Dietetics suffers from the same issue that mental health does: there's an underlying stigma that causes people to inflict a moral judgement on the ill; fat people - or so the old line of thinking goes - are immoral. A shocking number of people, including many doctors and scientists, view diabetes as a "fat people disease," and that diabetics are in effect being punished for their gluttony. This isn't always a conscious bias, but it has very negative effects.

It reminds me of the studies they've done in Canada and the US about how natives (American Indians) die a lot of the time in the ER because they're immediately written off as alcoholics or drug-addicts, and so their complaints are evaluated through the lens of "this person just wants opiates."