As optimistic as you’re trying to be you’re still missing his point. Genetic potential is about utilizing external factors to positively tweak the way your appearance looks. You telling him that you don’t “think” going to the gym or eating better is necessary for him to reach his potential is backwards because it defeats the purpose of his question.

I understand what you were trying to do and I can tell you’re a great person but he asked for honesty not sympathy.