why you can't sit down to eat without making a statement

Analogy: "there's hardly a meal that dosn't relate to legislative food fights in Washington," by comparing the in fighting of the legislature to food fights. The use of this analogy works in a couple of ways; it aludes to a very childish activity. it also relates to the article as a whole from a food perspective.
Imagery: "13 percent of its food-56 percent more than two decades ago" the author makes it seem by emphasizing 56 that the increase is much greater than it really is.
undrestatement: By saying that purchasing mccnuggets is a tacit approval of big agriculture he is stating how much power the consumer has.