Originally Posted by t-bone2
Make sure the peanut butter is the natural variety, otherwise drop it.
How much water are you ingesting each day? Be sure to stay well hydrated. You should be drinking water throughout the day.
Also, you need to add some Essential Fatty Acids (EFA) to your diet. Many people supplement with fish oil/capsules to increase their Omega 3 consumption. 2-3 capsules with each (or most) of your meals should suffice.
Try the suggestions here and keep running for a few more weeks to see what happens. Sometimes it takes a while to see results, but minor tweaks to diet, cardio and weight training will pay off over time.