Katie Byrne: Since when did celebrities become experts on the subjects that matter?
A common thread emerges when you look at some of the diet books that arrived on bookshelves earlier this month.
The new wave of experts are, by and large, not dietitians. They haven't studied human nutrition nor do they have fitness qualifications.
They have something that the average diet expert doesn't have, though: celebrity. And as we all know by now, that's all that really matters.