why pizza is a vegetable

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.


10 responses to “why pizza is a vegetable

  • Alex Mills

    Apparently the Reagan administration once tried or successfully made ketchup count as a vegetable. I found that funny.

  • Tallys Yunes

    Ah, come on! Now you made me want pizza…To make things even worse, UM now has a pizza truck on campus.

  • Florian Bahr (@fbahr)

    First things first: In 2010, the EU has issued a regulation that defines what an “authentic pizza” is (and how it is to be manufactured and …everything):

    [Commission Regulation (EU) No 97/2010 of February 4, 2010, entering a name in the register of traditional specialities guaranteed: Pizza Napoletana (TSG)](http://goo.gl/yrbCh)

    So, this concise document (of “only” 10 pages) clearly states: A pizza is a pizza only if at least 60 and no more than 100g of tomatoes are “processed” in the toppings.

    Now my important question: w.t.h. is a “cup of tomato[-es| sauce). In grams or mililiters, please.

    [PS: Wolfram Alpha says ~250g.]

  • Laura McLay

    @Alex I heard that Congress once tried to legislate the value of pi to be exactly 3.

    @fbahr I am not surprised! German has beer purity laws. Pizza purity laws would then be natural. The question is, does this rule hold for pizzas of various sizes? One serving of vegetables is ~113 mL (half a cup). It looks like EU pizza is not quite a vegetable either.

  • Laura McLay

    @fbahr: That pizza document is something else. Apparently, EU pizza cannot come in too many sizes:

    ” ‘Pizza Napoletana’ TSG is a round product baked in the oven with a variable diameter not exceeding 35 cm and a
    raised rim and the central part is garnished. The central part is 0,4 cm thick, with a tolerance of ± 10 %, and the
    rim is 1-2 cm thick. The overall pizza must be tender, elastic and easily foldable into four. “

  • Florian

    @Laura: You know, in Europe water (officially) doesn’t prevent dehydration …is there anything more I’ve to say about food regulations? – But, you’re right: pizza is neither “a vegetable” nor does it fulfill the requirements of a “balanced meal”. That’s why canteens have to serve an aditional mixed salad (or something like that). [Up to now, you won’t be _forced_ to eat it, though.]

  • Tallys Yunes

    @Florian: Wow! I’m in shock of the water statement!

  • Matthew Saltzman

    @Laura and @Alex: Easy enough to check: http://en.wikipedia.org/wiki/Indiana_Pi_Bill (a bill in Indiana in 1897 claiming a method to square the circle, which implied various incorrect values of pi, and which was passed by the legislature but died in the senate thanks to the intervention of a passing math professor), and http://en.wikipedia.org/wiki/Ketchup_as_a_vegetable (a regulatory proposal–not a bill–that never was implemented).

  • Laura McLay

    Thanks for the link, Matthew! I didn’t have the time to hunt around for it. Pizza being a vegetable is small potatoes (pun intended) compared to Congress botching math.

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