Running and Nutrition

Question
Hi Kimberly,

I'm a 24 year old male, approx 5'6'' and approx 133 pounds. I have been running for over a year now (regularly run 10K, Cross-country and half marathons). My times are quite good (sub 38 10K and sub 1:25 half marathon) but I feel like I am not reaching my full potential because I know I don't eat properly. I've been searching the internet for nutrition advice relevant to my circumstances but have been unable to find anything that helps. So I have a couple of specific questions please!...

1. I run approx 30-35 miles per week at the moment although I'm about to increase this hopefully to about 40-45 miles. How many extra calories should I roughly be taking on board to account for this to maintain my current weight and should I be concentrating on carbohydrates? (I know practically nothing about carbs/protein/fats etc apart from the basics!).

2. I'm now at the stage where I'm getting a bit skinny and I want to start adding a little bit of muscle without becoming too heavy. I've heard that running actually undoes any work put in to build muscle...is this true? Also, considering that I will still be running the same distances...should I be changing my diet or amount of calories with a view to gaining muscle too?

Also if you have any general advice that you could throw my way, given my circumstances, I would be most grateful!

Thanks for your time!
Paul

Answer
In really am not a sports nutritionist and that would be the person who could answer your questions.  I recommend http://www.nancyclarkrd.com/  Nancy Clark is a RD who does specialize in this area.  She has some great books that could help you out!!  
Kim Tessmer, RD LD
www.Nutrifocus.net

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