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High in fat
Mark Poprocki—Mark Poprocki

This Is the Worst Kind of Fat for Your Heart

Aug 11, 2015
TIME Health
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As confusing as the diet message can be at times, one thing is clear. There are good fats and bad fats in the foods we eat, and some can really wreak havoc on the heart and its delicate vessels.

In a study published in the BMJ, scientists say that trans fats are linked to the highest rates of death from all causes, deaths from heart disease and heart problems. The trans fat risk surpassed even that associated with saturated fat, which is found in formerly taboo-for-the-heart foods like butter, eggs and red meat.

Russell de Souza, a dietician and epidemiologist from McMaster University, and his colleagues sifted through the published studies involving hundreds of thousands of participants on trans and saturated fats and their health effects. They found that those eating more trans fats had a 34% higher rate of dying from any cause compared to those eating less, a 28% higher risk of dying from heart disease, and a 21% greater risk of having heart-related health issues.

MORE: This Is Why FDA Is Banning Trans Fats

In contrast, eating saturated fat was not linked to a higher risk of early death, heart-related problems, stroke, or type 2 diabetes.

That doesn’t mean, however, that saturated fats now get a green light. de Souza points out that many people who try to cut back on saturated fats tend to substitute them with less healthy fats like those from margarine or with carbohydrates, which can contribute to heart disease. So while saturated fats when compared to trans fats did not substantially increase heart disease risk, that doesn’t mean saturated fats are actually heart healthy. It’s just that in the hierarchy of heart-friendly fats, trans fats are the worst and saturated fats are the next worst. “We didn’t find any evidence for increasing the allowable amount of saturated fat in the diet,” says de Souza.

MORE: Trans Fats Are Hiding All Over Your Grocery List

The group that showed the lowest risk of early death or heart disease were those who consumed the most vegetable oils such as olive and canola. “If there is one message to go away with from these results, it’s that substituting saturated and trans fats with whole grains and vegetable oils is a step in the right direction,” says de Souza.

The results, he says, support current dietary guidelines for how much of different types of fats people should eat to maintain healthy hearts and lower their risk of chronic diseases. For now, he says, the advice to consume no more than 10% of daily calories in saturated fat and to limit trans fats to less than 1% of calories, is reasonable.

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