In my experience (rural), all rodents will eat anything they can reach. I'm sure that if you give them a free choice between sunflower seed and white flour, most will prefer the seed, but I'm not aware of any food they shun when hungry.
And, I hope you know that lab-white rats are no relation to wild critters. We have 9 species of rats/mice here in Ottawa. No matter where you live in the world, you probably have a similar variety.
