Farah: Health officials know that in East Asia cancer is much less common than it is in North America. And it is widely known that typical East Asian diets include a larger proportion of whole grains than typical North American diets do. So North American health officials are derelict in their duty to protect the public health if they do not encourage North Americans to increase the proportion of whole grains in their diets. Prasad: Tea contains substances that can help prevent several types of cancer, and tea is consumed much more widely in East Asia than in North America. Prasad responds to Farah by ["undermining Farah's argument by providing evidence that supports an alternative explanation", 'demonstrating that the beneficial effects that Farah attributes to diet can be counteracted by other factors', "calling into question the accuracy of Farah's claim concerning the proportions of whole grains consumed in East Asia and North America", "introducing further evidence that supports Farah's conclusion"]