Is a vegetarian diet an effective way to lose weight?

I’m about to graduate from college. This summer I’m working overseas for a study abroad program. I’m trying to lose some weight before I go. I’m doing some aerobics to get my body prepared for the P90X workout. Here is what I’m asking. Will a vegetarian diet help me lose weight effectively. The only meat I eat is tuna. Other than that, I consume eggs, milk, beans, or peanut butter for my protein source.