What I'm eating enough to support weight loss?

I'm trying to lose weight, and I just began cutting out diet sodas and any drink with sweetener in it because I heard that can cause an insulin spike and make you hungry all day. I usually start with a banana for breakfast. A handful of whole wheat crackers for a snaker. A small sandwhich and a salad for lunch. sometimes raisen bran for a snack or something of the like. Is that enough to do the job?