Spoiler alert: It isn’t pretty.

Your stomach literally gets bigger

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It’s no exaggeration that you ate more than your stomach wants to hold. When you keep eating once your stomach is full, it will keep expanding to make room for more food—and that’s when you get uncomfortably full. “If it’s stretching larger than its normal size, it can put pressure on your other organs,” says registered dietitian nutritionist Jenna Braddock, MSH, RD, CSSD, LDN, founder of MakeHealthyEasy.com. By the time you’ve digested your feast, though, your stomach size will go back to normal. At least it usually does—crazily enough, some people’s stomachs stay stretched out. One big meal (or even one holiday season) of unhealthy foods shouldn’t do any permanent damage, but if you’re constantly overeating, your stomach might learn not to bounce back, says registered dietitian nutritionist Caroline Passerrello, MS, RDN, LDN, spokesperson for the American Academy of Nutrition and Dietetics. That means the next time you eat, you’ll need to eat more to feel full, and the cycle of overeating will continue. Don’t miss these 12 reasons your stomach is bloated and when to worry.

Your food starts backing up

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After overeating, you might start feeling a burning sensation in your chest or throat. That’s because an expanded stomach messes with the ability for the opening between your stomach and throat to stay closed. “Your stomach is so full the food starts backing up,” says Passerrello. Try these 13 natural heartburn remedies to get some relief.

Your digestive system becomes an energy hog

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Don’t blame the tryptophan in turkey for putting you in a food coma. Protein (like in turkey) and fatty foods (like in basically everything else on your plate) take a long time to digest, so you could spend up to 12 hours feeling the effects of your Thanksgiving dinner, says Braddock. While your body is focused on breaking down that massive feast, it sends more blood to the digestive tract, she says. Your brain and the rest of your body are getting less blood than they’re used to, so you start feeling that familiar post-binge sleepiness. (Learn more about why we get tired on Thanksgiving.) To combat it, resist the urge to nap and go for a walk. “You’ll use some of that food you ate instead of storing it,” says Braddock. “It’s helping the blood flow go through the rest of the body.” Fill your plate with these 10 healthy Thanksgiving foods to ward off the energy spike.