I read once that how you look is more than 80% what you eat. (hence the reason I am fat)!.
You can eat acceptably at Mcdonalds...just get a grilled chicken sand with tomato and onion and dont eat the bread for example. Drink more than a gallon of water per day...closer to 2 would be better.
While not easy, the formula is easy...you have to burn more energy (calories) than you take in. And the better you eat, the easier that will be to accomplish.
Another suggestion, run your dryfire sessions like we did in the academy, insert sets of pushups, situps, jumping jacks, seal kicks, etc into the routine.
That and hit the gym every time you can...it will become part of your routine if you keep at it.