Why These Cancer Recommendations?

Walter Willett, MD, DrPH, an epidemiology professor who leads the nutrition department the Harvard School of Public Health, was on the international team of scientists that wrote the recommendations.

At the ADA meeting, Willett said the first recommendation -- to be as lean as possible within the healthy weight range -- is "the most important, by far."

But there is one recommendation that Willett says may be a "mistake" -- the one about not taking supplements. Vitamin D supplements may lower risk of colorectal cancer and perhaps other cancers, notes Willett. He predicts that that recommendation will be a top priority for review.