Will this help me lose my beer belly?

I am not too out of shape, but I want to get in a lot better shape. I would like some thoughts on my current diet on if this will help my cause.

Breakfast
Protein shake
Mid morning snack
Tuna salad on toast
Lunch
Handful of almonds and a fiber bar
Mid afternoon snack
4 peanutbutter crackers and some sunflower seeds
Supper
A few light beers and the rest varies, but i am cutting down my portions dirasticly for this meal
Snack(rarely)
Air popped popcorn

I am also taking in about 150oz of water a day. This keeps me from getting too hungry, but is it still too much?