Lots of food, lots of protein, lots of complex carbs. Eat fatty fish 5 days a week, dozen eggs a day. Use creatine HCL, not monohydrate, before and after workouts, 2 grams each. Also 60 grams of fast digesting carbs immediately post workout. Dextrose is best.
Also, ask them to define natural. Not everyone means the same thing when they use that word. I had a buddy that believed that "true naturals" don't even use whey protein, bcaa's, DHEA, creatine, or any form of legal nutritional supplements. I deal with another competitor at my second job that says as long as it can be purchased legally without a prescription, he considers it "natural". For him that includes products like those from IronMag Labs, which I definitely wouldn't consider to be natural, but he's perfectly fine with it.
Everyone defines natural differently. Find out what he considers natural, and work within those limitations.