There's a theory that you go off things that are more likely to be slightly off - so fruit, meat, cheese etc, all good for you, but more likely to be contaminated or slightly off than dry salty things like crisps. I suppose the theory is that your body is especially cautious in the first trimester when the developing baby is very vulnerable.
midget your consultant was talking rubbish because hyperemesis is most common in the Asian subcontinent (much more than here).
I was so ill with hyperemesis (multiple hospitalisations, loads of drips etc) that a hundred years ago or in a less developed country I would probably not have survived. But a few studies have suggested that even hyperemesis correlates with some advantages (assuming you survive!) - for instance a better quality of placenta. It must be good for something!