High carbs, high protein.... this is when you are trying to put on alot of body mass over a set period of time. You will gain alot of muscle mass from this type of diet as the body has a surplus of protein/carbs in order to grow new muscle tissue. However, the body tends to store more fat on this diet because of the added surplus so expect to gain a few inches on your waist and lose muscle definition.
When i was bulking (for 9months), i was taking in around 400g protein and 500g of carbs. I went form 165lbs to 210lbs (clean)... I put on a few inches round my waist etc, but i had the muscle mass i wanted.