I was told the same when I was first diagnosed, I was also told not to test my blood sugars. I decided that knowing my blood sugar levels was probably a good idea so got myself a meter.
The meter showed me what terrible advice the oats for breakfast was, oh and what she said about choosing wholemeal bread was also just plain wrong.
Strangely enough the breakfast she frowned on when I mentioned it, bacon and eggs, is absolutely fantastic for my sugar levels.
My new best friend (the glucose meter) seems to know more about what causes high sugar levels than my nurse.
Funny thing is that when I had cut most of the higher carbs foods from my diet, not only did my blood sugars drop to below the diabetic threshold, my IBS miraculously disappeared.