Saturated fats should still be eaten in moderation. But when compared to other evils, a new study shows, they're not quite as bad as we might have thought.

New research from McMaster University shows that trans fats are associated with greater risk of death and coronary heart disease, and should probably be avoided.

But when you compare the two, trans fat's less evil cousins – saturated fats – don't seem to have the same association. In other words, saturated fat is not associated with an increased risk of death, heart disease, stroke and type 2 diabetes.

This revelation isn't entirely new, said Russell de Souza, an assistant professor in clinical epidemiology and biostatistics at the DeGroote School of Medicine. He led the study, which was published Tuesday in the British Medical Journal.

But the study does give an updated review of existing evidence, and will help guide professionals advising people on food guidelines.

"I don't know that we found anything new about saturated fats," he said. "But we did learn how bad saturated fats are depending on what we compare them to."

Saturated fats come from animal products such as milk, butter, meat and egg yolks, as well as chocolate and palm oils.

Trans fats, meanwhile, come from industrially produced food such as snack foods, packaged baked goods and margarine.

De Souza still doesn't recommend that people eat more saturated fat. His data was mostly observational, he said, and there are numerous studies that warn people to curb saturated fats.

But it does show that there's no noticeable difference between saturated fats and those illnesses, whereas there is with trans fats.

Overall, "I'd encourage people to focus on the whole diet," he said.

"Our hope is that this project would help committees that are setting guidelines for saturated and trans fats for how to steer the public," he said.

"On the whole, our research supports the efforts to keep trans fats as low as possible."

De Souza's study found that consuming industrial trans fats was associated with a 34-per cent increase in death for any reason, a 28-per cent risk of chronic heart disease death and a 21-per cent increase in chronic heart disease.