Your waistline isn’t fooling you: The Grinch’s heart isn’t the only one growing three sizes this season.

After enjoying a delicious holiday spread, your stomach expands generously to accommodate that extra serving or two, which would explain the snug pants after the meal.

Although the stomach is usually the size of a soda can, it can grow to the size of a 2-liter bottle of fluid, which is great news for those who want an extra piece of cake.

“It’s going to quadruple or more in size,” said Dr. Arthur Beyder, associate professor of medicine and physiology at the Mayo Clinic. Live Science.

He likened the smooth muscles of the stomach to “a rubber band,” due to the muscle’s ability to contract after being stretched for a long time.

“You pull on it and it will bounce,” he added.

This is especially helpful when the body ingests a large amount of food at once, such as during a holiday feast or mindlessly eating a snack in front of the television.

While competitive eaters might be able to fill their bellies with up to 4 liters of food, the average person would not be able to achieve this, despite the stomach’s ability to expand.

But if you’re feeling too full after another helping of turkey or potatoes, Beyder advises against lying down, which can cause acid reflux. Instead, he recommended taking a walk, which Live Science says can aid digestion.

Other experts also advised drink plenty of water after a cardiac meal.

“Leftover Thanksgiving food is amazing, so you don’t have to eat it all on the first try,” Beyder said.

“Sit there and talk for 15 minutes before coming back for seconds.”