In a study of nearly 2,000 heart attack patients presented to the American Heart Association in 2000, eating a very large meal quadrupled the risk of having a heart attack within two hours of the meal in those with cardiac disease, according to a recent report in Consumer Reports on Health.
There could be a number of reasons why a heavy meal could trigger a heart attack, said Dr. Marvin M. Lipman, the chief medical adviser to Consumers Union, who wrote the article. Blood is diverted away from organs such as the brain and heart and into the gut to help digest the big meal, which can take hours. A heavy load of carbohydrates causes insulin levels to rise, and that can prevent blood vessels from relaxing to handle the increased cardiac output.
Triglycerides, a type of fat, can cause the cells lining the blood vessels to be stiffer or inflamed. Blood pressure can rise as a result, which can be a problem for those with heart disease, Lipman said.
"That can have deleterious effects on already-existing plaque in the coronary arteries, such that they rupture and block the artery, and that can cause a heart attack," he said.
It also might help explain another morbid holiday association. A 2004 study published in Circulation found that the rate of unexpected deaths peaks around Christmas and New Year's Day. Overeating "is one possible explanation," Lipman said. Alcohol intake tends to go up around the time of holiday parties, and that could also be a factor. There's another factor that could implicate overeating in the death rate mystery.
"There's also a peak on Super Bowl Sunday," Lipman said, which has been called the second-biggest day for gorging, after Thanksgiving.
Unfortunately, many of the classic signs of a heart attack -- pressure in the chest, sweating, shortness of breath -- can be symptoms from overindulgence, he said.
"It's hard for a patient to differentiate between the physical effects of overloading the stomach and the actual effects of having a heart attack," Lipman said.
The best bet is just not to overdo it if you could be at risk, he said.
"The kicker is that not everybody knows that they have heart disease," Lipman said. "The advice would be if you have known heart disease obviously be careful. But if you're being treated for risk factors for heart disease, such as high cholesterol, hypertension, diabetes, then you should be careful as well, even if you don't have known heart disease."