I agree Cherie. When I was first diagnosed, I had over 40 lesions, but I was an extremely physically fit person. The AF let me stay in the service after my diagnosis--because I was still running circles around the 20-year olds. It wasn't until I had a lesion that formed on my brainstem that I experienced serious and lingering issues--then the AF did medically retire me. Long story short, location of the lesion(s) is the key, quantity means nothing.
I also agree MS is likely caused by a combination of issues; most predominantly genetics, but I think environment plays a role too.
I doubt diet causes MS--and I doubt it can cure it (even though there have been some promising results from some diets). But as eat2bwell and you point out, a healthy diet will improve anyone's quality of life, whether you have MS or not--so why not follow one?