"It’s not so easy to just say no when you keep getting invited, and it’s all out there in front of you,” admitted the 55-year-old stockbroker, a long-term patient of mine. He was offering a timeworn excuse for the 5 pounds he gained during a culinary caper that began with Thanksgiving dinner and ended with an all-day open house on New Year’s.

How bad can it be to overindulge on the holidays? Fortunately, most people get away without serious consequences. But for those with risk factors such as heart disease or high cholesterol, overeating can set off more serious medical problems. As for that weight gain, it might not be so easy to take off.

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A Pain in the Gut

What happens when you’ve stuffed yourself? Heartburn caused by acidic gastric juices refluxing into the delicate tissues of the esophagus can last for hours. Try an over-the-counter antacid such as Tums for relief. For gas and diarrhea, try some bismuth subsalicylate (Pepto-Bismol and generic)—or just wait for it to work its way out, as it were. Read more about the best ways to treat heartburn.

The fat in your feast can precipitate gall-bladder attacks. And if you’re susceptible to gout, which is the painful buildup of uric-acid crystals in your joints, go easy on alcohol and red meat. An overload of salty appetizers can result in swollen ankles for a few days.

If you have coronary heart disease or are at risk for it, overeating (a big Thanksgiving or Christmas dinner can top 5,000 calories) can have serious consequences. A study of almost 2,000 heart-attack patients suggested that a single act of overeating could quadruple one’s chance of having a heart attack on the same day. Triglycerides­—a type of fat in the blood after a large meal—can cause coronary artery inflammation, commonly a prelude to a heart attack. Large amounts of food and alcohol can cause the release of adrenaline-like substances that can cause a fatal abnormal heart rhythm.

Even if the most dire consequence of overeating is a few extra pounds, can you drop them easily? No, according to a study in The New England Journal of Medicine. It looked at holiday weight gain in 195 adults who worked at the National Institutes of Health. Contrary to expectation, they gained only a little more than a pound, on average. But they didn’t take it off the following spring or summer, putting them at risk for long-term weight gain.

A Healthier Holiday

Most of us can’t make it through a whole season of holiday parties without splurging a little. Here are a few ways to control your holiday food intake.

  • Don’t go to a festive meal feeling famished. Eat a high-protein snack beforehand, such as a slice of cheese, to take the edge off your hunger.
  • Be choosy about your hors d’oeuvres. Avoid anything fried. Eat a good helping of salad first.
  • Eat slowly. Swallow each mouthful before taking the next and chat with a table mate between bites. Slow eaters tend to eat less food.
  • Party buffet? Position yourself as far away from that table as you can get.
  • Increase your regular exercise schedule to burn off some of those excess calories.
  • If you end up overdoing it one night, don’t use it as an excuse to blow the rest of the season, as my stockbroker patient did. Simply get back to your usual (and better) habits the next morning.