Thermic Effect of Food aka Specific Dynamic Action

Thermic effect = energy your body must expend to digest, absorb, and transport food

Different macromolecules take different amounts of calories to process:
Protein: 20-35%
Carbohydrates: 5-15%
Fat: 0-5%
(1)

It is hypothesized that leaner individuals have a higher thermic effect percentage and some individuals use up to 10% of their daily calories to digest food. (1,2)

Thermic effect from carbs is much higher directly following a workout, making this the prime time to eat an abundance of carbs.  Not only will you fuel your muscles and shuttle protein into them, you can enjoy a high carb meal that might normally put you to sleep. (2)

1 http://www.bodybuilding.com
2 http://eattoperform.com
3 http://www.livestrong.com