I don't know if Politifact is considered reliable here but here's what they say.
"But is this the great Reagan ketchup debacle?
The same amount of ketchup, according to the USDA, sneaks in about 10 times the sodium, contains just a third of the protein, less than a tenth of the fiber and more carbs and sugar. It offers smaller traces of vitamins, and half the beta carotene and lycopene. Tomato paste is not ketchup.
Still, frozen pizza manufacturers and the frozen food industry did push hard to keep the vegetable designation for the tomato paste on the pizza. When it does, that's one less vegetable the school has to buy and a cheaper deal for school districts.
Fewer vegetables for kids may not be exactly a win for America. But did House Republicans try "to classify pizza as a 'vegetable' for the purpose of school lunches"? They did fight for the classification for the sauce on the pizza and blocked a move by the Obama administration to boost the amount of tomato paste needed to count as a serving of vegetables. But they didn't try to classify "pizza" as a vegetable. And even the amount of tomato paste required, just two tablespoons, packs nearly the nutritional punch of a half-cup of other foods we consider healthy. That's a pretty important detail to omit. We call the Democrats' claim Half True."
http://www.politifact.com/truth-o-meter/statements/2011/nov/22/democratic-national-committee/republicans-pizza-vegetable-school-lunch/