It's not surprising that the question "Does your stomach shrink when you eat less?" is frequently asked. It almost sounds too good to be true for those who want to lose weight: All you have to do to downsize your stomach, and therefore reduce the amount of food you need to eat to feel full, is eat less. It's like gastric bypass without the surgery. But in reality, this issue isn't so simple.
Stomachs are elastic; they're made to stretch so you can fill them to the brim with delicious foods. This ability was useful during times of famine when the body would stock up because a next meal wasn't always guaranteed. However, it's a lot easier to find food these days.
But does your stomach shrink if you eat less? Well, that's where things get tricky. There isn't an inverse relationship between stomach size and food portions; basically, your stomach won't shrink if you eat less. Your stomach will snap back to its original size after a feast, but it won't dip below its normal size if you stop eating.
If stomachs kept shrinking the less a person ate, it would follow that thinner people have smaller stomachs than obese people because they eat less overall. But in fact, a December 2006 study published in the journal Gerontology found that most people tend to have similar size stomachs.
Eating less in hopes of narrowing a tummy could actually backfire, according to Nitin Kumar, MD. "Your body begins to think that you're starving. So you get multiple physiologic and hormonal responses to try to get you back to your weight," Dr. Kumar told Prevention.com. Cutting calories floods your brain with hunger hormones and simultaneously slows your metabolic rate so your body can conserve its energy.
The moral of this story is don't cut portion sizes in hopes of stunting your stomach. Instead, you should slowly reduce your caloric intake, Kumar said. By doing so, you won't shrink your stomach, but you can still satisfy your appetite faster.