I changed the recipe by using a Pillsbury thin pizza crust instead of a frozen dough. I spread a mixture of ricotta (part skim), fat free mozzarella, freshly grated Parmesan, minced garlic, and a little skim milk on it. Then I topped it with some sautéed spinach and garlic.
One fifth of the pizza (three squares the way I made it) is less than 400 calories. Honestly? I could've (easily) eaten more than a fifth!