I can't give you a scientific answer here, however, my sister had gastric bypass 3 weeks ago today, so I thought I'd bump your post. Besides the small amounts of pureed food she can eat, she's also required to drink 32 ozs. of a protein drink, as well as 32 ozs. of other liquids. She also takes some kind of supplements. I think this helps your body from going into starvation mode. Just because your body can't tolerate "large meals", it doesn't mean you'll go into starvation mode. I think once your body gets used to smaller portions (rather than the HUGE ones we get here in the U.S.), things even out.

BTW, she's lost 25 lbs. in 3 weeks.