Protein

Protein requirements for runners are somewhat controversial. I'd recommend starting with these two articles that give good, research-based advice.

• International society of sports nutrition position stand: nutrient timing
• Examine.com How much protein do you need per day?

My personal observation as a relatively lean runner doing relatively high mileage, it seems that higher protein intakes have been beneficial to recovery and body composition. It also seems that timing my protein and carb intake so that my body doesn't break down muscle to replenish Glycogen stores after High Intensity Interval Training is also important.