The word "which", by its definition, is "asking for information specifying one or more people or things from a definite set." So, naturally, "which foods do you..." is the correct way of phrasing this question, right? But some people tell me that "what foods do you..." is the correct way. This phrasing even returns more Google results — 1.4 million as compared to 221k for "which foods..."
So which one... err... what one is correct?