(CBS News) — For years, the mantra has been that eating lots of fruits, vegetables and grains will ward off heart disease, but a new study suggests that choosing the wrong ones may backfire.

The study, of over 200,000 U.S. health professionals, found those who ate plenty of healthy plant foods — such as vegetables, beans and whole grains — did have a lower risk of heart disease.

That was not true, however, if people loaded up on foods that are technically plant-based, but not all that healthy.

In fact, diets heavy in pasta, bread, potatoes and sweets appeared just as bad as, if not worse than, diets high in animal products.

So it’s crucial that people consider the nutritional quality of the plant foods they choose, she said.

The study did not specifically examine vegetarian or vegan diets, Satija noted. So the findings do not shed light on how those diets affect heart disease risk.

But other studies have tied vegetarian and vegan diets to lower risks of diabetes, high blood pressure and heart disease, according to Dr. Kim Williams, chief of cardiology at Rush University Medical Center in Chicago.

“Plant-based nutrition is superior when it comes to most diseases,” Williams said.

“But what people don’t always understand is that there are healthy ways to do it, and not-so-healthy ways,” he said. “You can do it wrong.”