You may have read that Congress is trying to declare that pizza is a vegetable. Apparently, that isn’t really what happened. Ezra Klein writes that the real issue is that “Congress passed a revised agriculture appropriations bill last week, essentially making it easier to count pizza sauce as a serving of vegetables.” I’ll explore whether pizza sauce should count as a vegetable.
Ezra Klein compares tomato paste to a raw apple to estimate how many tablespoons of tomato paste are equivalent to a serving of vegetables. This is the right idea but it’s problematic because he compares raw food to cooked food as well as apples to tomatoes.
Let’s not compare apples and oranges (er, tomatoes). Let’s see how many tablespoons of tomato paste are equivalent to one serving of tomato sauce. Tomato paste is tomato sauce that has been cooked until most of the water is removed. We’ll find the amount that the tomato paste has been reduced. I’ll assume that one half cup of tomato sauce is one serving of vegetables, consistent with the recommendations of the American Dietetic Association. Note that one half cup = 8 tablespoons. This type of analysis takes advantage of the fact that the nutritional value of the fruit/vegetable can be condensed and stored a smaller volume after the water is removed (e.g., a bunch of grapes can be dried and stored in a small raisin box).
One serving of tomato sauce has 51 calories, 26% of Vitamin A, 53% of Vitamin C, and 10% of iron (in terms of RDA recommended levels). Two tablespoons of tomato paste contains 23 calories, 9% of Vitamin A, 10% of Vitamin C, and 5% of iron. By using analytical methods (read: arithmetic), we can estimate that it takes 4 – 10.6 tablespoons of tomato paste to equal one serving of a vegetable (tomato sauce). Leaving out vitamin C, our estimate narrows to 4-5.8 tablespoons. This means that Congress is way off. Apparently no one in Congress can do arithmetic.
Tomato sauce is actually not used in pizza (at least any decent pizza that I’ve heard of!) One can make a tasty pizza sauce from crushed tomatoes, which are not as concentrated as tomato paste. Crushed tomatoes are similar in nutritional content to tomato sauce, which brings us back to our base case estimate for the amount of pizza sauce that counts as a vegetable (half a cup). A normal serving of pizza does not contain half a cup of pizza sauce unless perhaps you are in New York, so I conclude that pizza is not a vegetable.
When I was in elementary school, I was told that sausage pizza has all four food groups in it. Food education and school lunches have gotten much better since then, but there still is room for improvement.