I find that having bread at lunchtime makes me feel lethargic, so I tend to have oat cakes instead. You can spread houmous or peanut butter etc on them, and honestly, because they are oats, they stop you from being hungry, and keep you going.
An apple or banana when you are flagging around 3pm is really great- so much better than chocolate, which will give you a sugar high, but then a bigger low.
I did a detox which meantthat my lunch was oatcakes, red grapes, a few nuts (unsalted) and an apple- and I was NEVER hungry. I just had bits of it throughout the day. I felt a lot healthier too.