Will this lower my body fat percentage?

I am 17 years old. I am 5 5 and weigh 140 pounds. I want to lower my body fat percentage. In the morning I a serving of oat meal. Lunch I eat burritos (from High Tech Burrito) or subway sandwiches (chicken foot long with lettuce, tomatoes, green peppers and american cheese). For dinner I eat salad with chicken. For snacks, I eat bananas, trail mix, and gs. I run 30 minutes on Monday, Wednesday, and Saturday. I also lift weights. Will this help lower my body fat percentage? Does anyone know where I can buy an easy to use body fat percentage caliper in stores?