This is entirely normal and is probably the first sensation you will have of “restriction”. All these operations work to reduce your capacity to eat by restricting the volume of the stomach or creating a small pouch which will fill up quickly. Your normal inclination will be to consume food and drink at the same rate and volume as you did prior to surgery, however this quickly fills the small pouch and causes pressure which gives rise to discomfort and sometimes nausea or vomiting. Remember to eat and drink slowly allowing plenty of time for passage through the restricted part of stomach before having another mouthful.