Your difficulty is going to lie in the fact that while there is truth in what you say, and it is good primary prevention, most of what you will practice as a APN is secondary and tertiary prevention, unfortunately. And when it comes to that, you have no choice but to practice EBM. Because if you treat the 60 year old obese pack-a-day smoker, post AMI pt with dyslipidemia and T2DM with niacin instead of a statin, when he drops dead of "the big one," you are going to be sued into oblivion and lose your home, your retirement, your job and your license. The time for niacin for that guy was in his 30s. Now he has to take the statin, he has no choice. It is statin, or death (unless he is unlucky enough to just have a near death CVA and survive as a veggie). The data on it is pretty cut and dried. There is no Big-Pharma conspiracy. Yes, it may elevate his liver enzymes, but without it his cardiac enzymes are going to be elevated, and a heck of a lot faster.
I hear ya on the lifestyle management, I really do. I am a believer. Prevention is the name of the game, and we really should be making it a priority as a matter of public health policy and spending. However, once you are practicing you are ethically bound to practice EBM and that means offering your patients the most up-to-date science. And nuts, twigs and niacin are not the most up-to-date science for anything.
Perhaps you might prefer to be a natropath or a nutritionist if your heart really isn't in EBM. However, you may be interested in the fellowship at the University of Arizona Center for Integrative Medicine. It was originally designed for MDs/DOs but was opened to NPs as well.
I believe it is about 30-40K, cash. It awards a certificate, not a degree, so no financial aid would be available. I had a friend who went through the program after we did our FNP. She loved it and thinks Andrew Weil hung the moon. I think he's a charlatan, but what do I know, lol. Good luck.