Skip to main content
LIMITED TIME ONLY: Join for as low as $10/month!

The difference between healthy and unhealthy fats

The science has changed, and now avoiding all fat isn’t the goal. Learn more about why and which ones most belong on your plate.

By Karen Ansel|Scientifically reviewed by Christie Sauer, M.S., RDN
Last updated December 22, 2025

In the early ‘90s, “fat” suddenly became a bad word, leading to a boom in fat-free diets that weren’t actually all that healthy or supportive of weight loss. Now we know that fat is an essential part of a healthy diet — necessary for giving your body energy, helping your cells function, and absorbing some nutrients and hormones.

But that doesn’t mean doctors are recommending unlimited butter, burgers, and fries. That’s because the type of fat you eat is important, and some kinds are better for your health than others. Here’s what else you need to know about the different kinds of fats.

Healthy fats


Unsaturated fats are beneficial: They can improve cholesterol levels, ease inflammation, and even stabilize heart rhythms. There are two kinds of unsaturated fat:

  • You’ll get monounsaturated fats in avocados, peanut butter, almonds, seeds, and canola and olive oils.

  • Polyunsaturated fats, including omega-3 fats, are present in fish, flax seeds, walnuts, and canola or soybean oil. Certain forms of these polyunsaturated fats (omega-3 and omega-6) are important because our bodies don’t make them, so we need to get them from food.


Learn more about easy ways to eat more vegetables

Unhealthy fats


Eating too much saturated fat increases your levels of LDL cholesterol — the harmful kind that’s linked to heart disease and strokes. You'll find them in pizza, cheese, whole and reduced fat milk, butter, ice cream, meat products (including sausage, bacon, beef, and hamburgers), coconut oil, cookies, cakes, and other grain-based desserts.

Swapping out saturated fats for unsaturated ones


The Dietary Guidelines for Americans recommends limiting saturated fat to less than 10% of your total daily calorie intake. Weight Watchers accounts for this and guides you toward healthier fats by attributing lower Points® values to better dietary fat sources.

Replacing saturated fat with unsaturated fat can help you stick to your Points budget, not to mention there’s evidence that swapping out saturated for polyunsaturated fat for saturated fat can lower your risk of heart disease.

Some easy ways to do that include topping your morning toast with avocado rather than butter or margarine, and when you’re cooking, replacing coconut oil with olive oil.


Learn more about the benefits of home cooking for weight loss

This content is for general educational and informational purposes. The content is not medical advice, does not diagnose any medical condition and is not a substitute for professional medical advice, diagnosis or treatment from a healthcare provider. Talk to your healthcare provider about any medical concerns.

Trust: You need this newsletter.

The field of weight management is evolving–and fast. New research. New treatments. Lots of misinformation. Our clinical newsletter helps sort it all out.