Your stomach is an elastic organ, so when you take in a large volume of food, liquid, or air, it does expand to accommodate everything that's put into it.
Q: Does your stomach really shrink and stretch depending on how much you eat?
Your stomach is an elastic organ, so when you take in a large volume of food, liquid, or air (think carbonation), it does expand to accommodate everything that's put into it. But it starts to shrink back to its normal size once the meal has passed out of the stomach. So overeating on occasion won't permanently expand your stomach and in turn won't make you hungrier.
There is, however, some scientific research out there suggesting that regularly restricting your food intake may reduce stomach capacity over time, possibly because the stomach wall eventually becomes more resistant to being stretched. (And vice versa with overeating.) But I still wouldn't recommend getting hung up on food restriction and stomach size as a weight-loss method. In fact, overweight people generally don't have bigger stomachs than thinner people.
There are a number of more important components of weight control, including hormone levels and psychological factors. While portion sizes do count, it's the quantity and quality of the calories that make up those portions that play the major role in weight management. Bottom line: Don't obsess over your stomach getting stretched.
Health’s medical editor, Roshini Rajapaksa, MD, is assistant professor of medicine at the NYU School of Medicine.