Fat 101: Saturated fat vs. unsatured fat

Masterfile

It's common knowledge that all fats aren't created equal. But it seems like every week there's a new study saying something different, and wading through all that information can be downright confusing (not to mention exhausting). Here, with the help of Mary Bamford, a Toronto-based registered dietitian, we give you the skinny on which dietary fats you should be eating, which are a sometimes indulgence—and which ones you should avoid altogether.

The good (Unsaturated fats)
Some are actually good for us, says Bamford. Unsaturated fats (monounsaturated and polyunsaturated) increase good HDL cholesterol while reducing bad LDL. Monounsaturated fats can be found in olive oil, canola oil, almonds and macadamia nuts; polyunsaturated are in corn oil, sunflower oil, salmon, mackerel and some nuts and seeds, and include omega-3 fatty acids, a type of polyunsaturated fat found in fatty fish, grass-fed meat and nuts. Omega 3s can help improve brain function and protect against heart disease and reduce blood pressure. Choose salmon instead of steak for dinner and toss some flax oil and walnuts into your lunchtime salad, or try cooking with avocado oil instead of vegetable oil. Your heart will thank you.

The not-so-bad (Saturated fats)
In the past, experts have told us that saturated fat increases the risk of heart disease. But a recent study out of the Harvard School of Public Health found that saturated fat intake wasn’t associated with heart disease or stroke. Bamford says finding a clear answer isn’t that simple; every study takes different factors into account (such as the amount of fat intake involved), and participants don’t always accurately report their food intake. She puts it this way: saturated fat isn't as bad as some fats, but it’s also not good for us. So we should still limit the amount we consume. “If you’re going to have a tablespoon of butter on your corn on the cob,” she says, “skip the pie for dessert and go for a piece of fruit instead.”

The ugly (Commercial trans fats)
Here’s the bad news: processed foods, like chips, cookies and candy bars, contain trans fats, which hit us with a “double whammy,” says Bamford. Not only does it raise levels of LDL cholesterol (the bad type), it also reduces levels of the HDL cholesterol (the good one), which protects against heart disease. Commercial trans fats (unlike natural trans fats, which are found in some animal and milk products and are harmless) are created when hydrogen is added to vegetable oils, which changes liquid oil to hard fat. Deep-fried dishes and fast food are widely-known sources, but some “healthy alternatives” like margarine contain the harmful fat as well. Go for products that contain non-hydrogenated oils over the ones that list any trans fat.