“Studies have found that eating just one meal high in saturated fat can be the tipping point that becomes potentially fatal, especially for people who have coronary heart disease,” says Chauncey Crandall, M.D.

 The latest research to illustrate the point was presented recently at the Canadian Cardiovascular Conference. In the new study, scientists compared the immediate effects of different diets on the arteries. Participants were fed a high-fat meal, and then a heart-healthy Mediterranean-style meal.

The Mediterranean meal consisted of salmon, almonds, and vegetables cooked in olive oil. The high-fat meal was a sandwich high in saturated fat consisting of sausage, egg, and cheese.

After each meal, the participants were given ultrasound tests to assess the function of their coronary arteries. The tests showed that immediately after the high-fat meal the participants’ coronary arteries were 24 percent less open than after the Mediterranean-style meal.

In someone with heart disease, this difference in arterial blood flow could mean the difference between having a heart attack or not having one, says Dr. Crandall, chief of the cardiac transplant program at the world-renowned Palm Beach Cardiovascular Clinic.

This isn’t the only study to track biological changes after eating a single high-fat meal. In 2007, a study showed that consuming high levels of saturated fat over several weeks caused adverse cardiovascular changes in 30 healthy young women.

Changes after eating a high-fat meal not only involve the heart’s coronary arteries, but also the consistency of the blood itself, says Dr. Crandall.

“After a high-fat meal, the blood becomes fattier and thicker,” he says. People who have coronary heart disease have deposits on their blood vessels that can cause clots, and, as a result of this combination, a clot can rupture, causing a heart attack, he added.

The lesson from the research is not that one steak dinner will kill you, but that such a meal does have an effect on your body, and that eating high-fat foods on a daily basis is a prescription for heart disease. “This type of lifestyle is not only unacceptable, but it can kill you,” says Dr. Crandall.

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