You can see that there are so many answers here, but only an RD should give out a meal plan. As personal trainers we are limited in our scope with regard to giving nutrition information. I’ve found over the years that many people know they need to eat healthy, but they need more help creating healthy habits–and changing their behaviors.
I have the ACE Health Coach cert and it definitely gave me tools I needed to understand behavior change and help clients make healthy, long-lasting lifestyle changes. The cert. helps you with clients to set goals, education, motivation, support and creating their program. (both with exercise and guidance in nutrition–no meal plans but you can review journals and make general recommendations). You understand what stage of change clients are in, and how to progress them to the next stage. As a coach, you educate, promote, and support clients in their efforts to eat healthy and exercise. I’ve enjoyed this cert and use it in conjunction with my personal training. It has helped me and my clients a lot.
Good luck to you– I know the nutrition piece can be a grey area. I also think a degree in psychology would be beneficial! 🙂