I had an endomorphic client who needed to increase calories. I had him eat five meals a day, and "chase" each one with a shake containing equal cals of protein (whey) and carbs. It was very difficult for him to consume this amount. I explained to him that if he continues to do this, he will gain weight. Once he reverts back to his "standard" way of eating, he will lose his gains. He couldn't keep up with the eating, and in fact, he lost the 10lbs he gained while I was training him.