From Dr. Mercola:
There are no “quick fixes” when it comes to losing weight, but if you’re looking for a way to “trick” your stomach into getting “smaller,” try eating smaller meals throughout the day.
The science is split on whether or not eating smaller meals more frequently will help you lose weight, but what it will do is make your stomach less stretchy, which in turn will help you to feel fuller when eating less food.
To be clear, it’s unknown if the actual size of your stomach can change. Most people’s stomachs hold about one liter of liquid, whether you’re 150 pounds or 300 pounds.1 However, it has an ability to stretch and expand when you eat a meal.
If you regularly eat large meals, your stomach’s distensibility (or ability to become stretched) will increase to accommodate the food. If you instead eat only small amounts at a time, your stomach’s distensibility will decrease.
Four to Five Weeks of Eating Smaller Meals May Change Your Stomach
If you want to shrink the capacity of your stomach, try eating smaller meals for at least four to five weeks. In a study of obese individuals, those who followed a restricted diet for four weeks experienced reductions in stomach capacity.2 As reported by Greatist:3
“Think of your stomach like a muscle. When it’s filled with large meals three times a day, the distensibility (the scientific term for the amount your stomach walls can stretch) increases — just like your biceps would get bigger if you were working them out three times a day, [Atif] Iqbal [M.D., medical director of the Digestive Care Center at Orange Coast Memorial Medical Center] says.
And when you head in the other direction — eating many small meals throughout the day — your stomach’s capacity goes down, says Rebekah Gross, M.D., a gastroenterologist and clinical assistant professor of medicine at NYU Langone Medical Center.
After about a month and a half of eating smaller meals more frequently, you’ll naturally feel full with less food, and your body will send signals to stop eating sooner ”
When you eat smaller meals more frequently, you’re not necessarily eating less food, just reducing the amount at each sitting, which makes it easier to stick with in the long term.
Drinking Water or Carbonated Beverages May Expand Your Stomach Capacity
Competitive eaters often drink large amounts of water during competitions because it helps the food to leave their stomach faster so they can eat even more.
Even during a regular meal, if you drink a lot of water or carbonated beverages, the excess liquid can cause your stomach to expand, leaving room for you to eat more food.4
This expansion is only temporary, fortunately, as is the stretching that occurs if you binge on a large meal (for instance on Thanksgiving or Christmas). The stretching is the reason why your pants feel tighter after you eat, then return to feeling normal after your food has been digested.