What You’ve Heard
The theory that saturated fat can lead to heart disease picked up steam in the late 1950s, when an international study found that heart trouble was more common in places where people ate a lot of red meat and dairy.
“Saturated fat raises LDL cholesterol, and cholesterol raises the risk of heart disease,” says Penny Kris-Etherton, professor of nutrition sciences at Pennsylvania State University. Recent guidelines from heart health education organisations around the world, recommend that people limit their intake of kilojoules from saturated fat to below 7%. If you eat 8700kJ a day, that’s no more than 16 grams of it a day (or roughly two teaspoons of butter).
But Not So Fast…
In 2014, a paper in Annals of Internal Medicine combined the result of 76 previous dietary studies, and found no sign that people who ate a lot of saturated fat were more likely than anyone else to suffer from heart disease.
Saturated fat can boost levels of LDL cholesterol, but those bits of cholesterol tend to be big and floppy, says Dr Peter Attia from the San Diego-based Nutrition Science Initiative, a nutrition and obesity research centre. This is important because it appears that small, hard cholesterol particles – the kind not associated with saturated fat – are more likely to clog arteries.
But it isn’t time to break out the bacon, says Dr David Katz from the Yale-Griffin Prevention Research Centre. The Annals study didn’t mean much, he says, because many of the study subjects who cut out saturated fat replaced those kilojoules with sugar and carbs. In other words, the study found that eating a lot of saturated fat is as bad as eating a lot of carbs and sugar – not that saturated fat is good for you.
The Bottom Line
Experts aren’t ready to rewrite the saturated fat rules yet. Red meat and butter can be part of a healthy diet, but not if you eat them with abandon. Today’s most relevant nutrition lessons come from the Lyon Diet Heart Study, a landmark investigation from the 1990s that still sets the standard for dietary research, Katz says. This study found that switching from a high-fat northern-European diet to a Mediterranean-style diet for nearly four years cut the risk of heart trouble by up to 70%. “Your diet should emphasise vegetables, fruits, and whole grains,” Katz says. “If you want to add fat, do it with salmon, nuts and seeds, with or without some lean red meat and dairy.”
Shopping around the edges of the supermarket will also help. It’s where the healthiest produce – fresh fruit and vegetables, meat and fish – is situated.