This is all good advice.
I have (mostly) stopped eating garbage and started running using a variant of 'Couch to 5k' and am getting a lot more out of every game.
My tactical gut is steadily chipping away and I can think clearer in my day-to-day, not to mention how much extra ability I have mentally and physically on the field.
Playing airsoft and playing airsoft at a competent level of fitness really are two different things.
This is a great excuse to improve your life with a high level of measurable returns!