Here is a study that used a double-blind two-trial crossover design to find that supplementing protein pre-workout can increase energy expenditure in the 48 hours following a workout better than having carbs pre-workout. The increased energy expenditure could facilitate reductions in body fat mass and improve body composition if nutritional intake is stable.
Timing protein intake increases energy ... [Med Sci Sports Exerc. 2010] - PubMed - NCBI
The one thing I am curious about is whether or not other protein sources would have the same impact as the whey used in the study? Any thoughts? I usually have a preworkout meal of oatmeal, eggs, and an apple. I am now wondering if I might have greater composition changes using a different pre meal.