Maybe eating a snack in between breakfast and lunch? It is a long period in between so your body might be retaining whatever it got from breakfast over to lunch, and so it doesn't burn it off.. If you eat a snack in between it'll let go of the fat/energy it got from breakfast quicker. And like twynnB says, you should incorporate more veggies in your menu! A min of at least 4.5 cups of veggies per day.
Are you getting enough water too? I drink about 2L per day, and you might also want to add some variety to your exercise routine.. (If you see that over time you are getting used to it, and it's getting easier.. you might need a challenge to surprise your body) And also make sure you're getting enough sleep!!
Hope this helps and keep on trucking!!