The standard four food groups are based on American agricultural lobbies. Why do we have a milk group? Because we have a National Dairy Council. Why do we have a meat group? Because we have an extremely powerful meat lobby.
—Marion Nestle
litotes
A figure of speech in which a positive is stated by negating its opposite. Some examples of litotes: no small victory, not a bad idea, not unhappy. Litotes is the opposite of hyperbole.