The pattern of the lines of the mushrom lead the eye toward the stem (?) of the mushroom and down the side of the picture. Also there is emphasis on the base because it is contrasting with the top of the mushroom.
Hm, I wouldn't have thought of a mushroom as healthy food, but I think you're right! The title seems a bit cheesy to me. As for the image itself, it is of course fantastic. I love the DOF, the detail, the lighting, and the rich color. Only negative things are the abnormal spot at the right center, and right above that there are some spots - would be nice to clone them out but obviously can't in a basic challenge. I think if you did that, though, this would make an awesome print or something... I really like it a lot. Great job!