Let's see...9 years on the ADA diet which many would consider "healthy" and "balanced" got me put on medication to control my by then out of control blood sugar. It also got my blood pressure out of control and my weight steadily climbing.
Now...let's see....2 years on a low carb diet and all of that has been reversed. No more need for medications, normal readings on all blood tests, weight down 75 pounds, blood pressure normal. 2 years isn't long term enough for you? Check out Richard Bernstein, a type 1 diabetic who has been eating this way for more than 40 years. Not many type 1 diabetics live as long as he has, let alone be in the great physical condition that he is; complication-free. Oh...he's also a doctor.
Thanks for your concern, but I'll stick with this if you don't mind.
I'm not sure what your definition of "healthy" and "balanced" is, but I eat fruit, vegetables, natural fats and proteins. What I don't eat is refined sugar, starches, flours, pasta, rice, and highly processed foods.