OK this might not be a popular response, but here goes. I was vegetarian for several years. At first I felt much better because I also stopped all the tons and tons of Sugar and refined carbs I was eating. Even though I took vegetarian cooking classes and knew how to balance the foods, I got weaker and sicker and sicker...
I do believe that animal foods along with some occasional beef is what my body needs. I believe that different bodies need different things. Now I do agree that if you can afford to buy the organic stuff without the animals being fed hormones and drugs and such - that's much, much better. Our local supermarket carries organic eggs, beef and chicken. If I can't get it though, I'll eat the regular stuff.
I also eat a lot of veggies and some fruit, nuts, dairy, etc. This is how I feel best though I've been well educated in my vegetarian days on the evils of animal foods including dairy. I try to plan my days so that I always have healthy foods available to me to help me avoid temptation. I also do the occasional cheat so that I don't feel utterly deprived and go crazy binging. However I don't keep any junk food in the house.
The sooner you start eating for health, the better off you'll be. Though some don't agree, I believe that what that means to one person can be different than for another.