Can vegetarians eat cheese pizza? This seemingly simple question has a somewhat complicated answer.

Vegetarians abstain from eating meat, game, poultry, game, fish, and shellfish. But, unlike vegans, vegetarians do not avoid all animal-derived products.

Based on that, it sounds like vegetarians can eat cheese pizza, right? Not always. There are subsets within the vegetarian community, including:

• Lacto-ovo: Vegetarians who eat dairy and egg products
• Lacto: Vegetarians who do not eat eggs, but do eat dairy
• Ovo: Vegetarians who avoid all animal products, except eggs 

Ovo vegetarians cannot eat cheese pizza, but that doesn’t mean Lacto-ovo and Lacto vegetarians will eat any cheese-topped pizza. That’s because some cheeses are made with an enzyme called rennet, which is traditionally harvested from an animal’s stomach after slaughter. Naturally, this can be problematic for some vegetarians.

While some cheeses are made with animal rennet, this enzyme can also be derived from vegetables and microbials. Good news for vegetarians: That’s usually the case for cheeses produced in the United States, including the standard low-moisture shredded mozzarella that tops most pizzas.

Many European cheeses are still produced with animal rennet, so some vegetarians choose to skip Parmesan and other cheeses on their pie. 

So, generally speaking, vegetarians can eat plain cheese pizza. Buon Appetito!