Ask the Diet Doctor: Importance of Polyunsaturated Fat

While you know by now that fats aren't evil (we hope!), find out exactly how much of each kind you should include in your diet.


Q: Should I eat more polyunsaturated fats than other types of fats? If so, how much is too much?

A: Recently, saturated fats have been a very popular topic in nutrition, especially as new research shows that moderate intakes of saturated fat may not be as detrimental to your heart health as we once thought. As a result, people have been touting the benefits of saturated fat while downplaying the role of polyunsaturated fats in their diets-which is a mistake.

If you want to reduce your LDL cholesterol, then increasing unsaturated fats (polyunsaturated and monounsaturated) while decreasing the saturated fat in your diet is the easiest way to do this. Before the benefits of unsaturated fats were fully understood, people were told to eat less saturated fat and to replace that fat in their diet with carbohydrates. (Find out if you're eating too many healthy fats.)

However, people didn't end up lowering their saturated fat intake-instead, they just ate more low-quality, refined carbohydrates (i.e. white bread), which didn't help the health of Americans at all. Instead, follow these tips to make sure you're getting enough of each kind of fat.

Keep It Balanced

I generally recommend that clients get one-third of their fats from saturated fat sources (butter, red meat, full-fat dairy), one-third from polyunsaturated (walnuts, fatty fish, canola oil), and one-third from monounsaturated (olive oil, avocados, macadamia nuts). You get into trouble when you start to drastically reducing or increasing one particular group. I cringe when I hear experts advise people to eat all the saturated fat that they want-that's just bad advice! Everything in your diet is about balance, when you eat more of something, you will need to eat less of another thing-and people always seem to remember the "eating more" part and forget the "eating less" part.

The newer saturated fat research suggests that eating refined carbohydrates instead of saturated fat is a bad idea-worse than if you just left your saturated fat intake alone in the first place. A better idea: Eat some (but not excessive) saturated fat, but also eat monounsaturated fat, polyunsaturated fat, and minimized the added sugar and refined grains in your diet as much as possible. (Try these 8 new healthy oils to cook with!)

If You Must, Lean Toward Unsaturated

If you tend to eat more of one type of fat, I would recommend eating more unsaturated fat (polyunsaturated and monounsaturated). Replacing excess saturated fat with unsaturated fat leads to a decrease in metabolically detrimental stomach fat that sits around your organs. Other research shows that if you overeat, then consuming more polyunsaturated fat (versus saturated fat) leads to less body fat. Even though saturated fat tastes delicious, and it is needed for various cellular and structural functions, the health benefit of eating extra saturated fat is generally overstated. (So next time you're in the kitchen, try these top substitutions for fatty ingredients that are better than butter.)

Go Nuts

You can obtain polyunsaturated fats in your diets from sources such as nuts and seeds, which contain both polyunsaturated and monounsaturated fats. Other sources of polyunsaturated fat include flaxseeds, flaxseed oil, canola oil, and toasted or regular sesame seed oil.

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