Don't feel stupid katie, there's so much conflicting information about that it's hard to keep track, and if you were told this by a dietician they were the ones that were supposed to have the knowledge and clearly didn't!
When I was discharged from hospital I was seen by a dietician just before I left. I had little or no knowledge about diabetes then, just all the normal misconceptions, so I asked her questions based on those assumptions. Could I have sugar in my tea? Could I have honey in my porridge? She said no, and basically gave me the impression that I couldn't eat sugar at all, it would have to be sweetener, I couldn't have things like peanut butter because of the fat, same for sausages. Couldn't eat ice cream, couldn't even have a glass of milk because of the lactose!
Basically, she was giving me the diet that someone looking to lose weight would need, despite the fact that I was seriously underweight at the time. I saw a different dietician a few weeks later and she allowed me much more freedom in my diet, so that it's now virtually the same as my pre-diagnosis diet.
I think that we forget sometimes that there are people who are bad at their job, just because they have some fancy title. They have to earn my respect now before I'll follow their advice.