Sunny side up egg on top of avocado and toast as example of fat that isn't always bad for you

Are Fats Always Bad For You?

Updated December 12, 2023.

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Fats, in the minds of some, are a kind of nutritional evil – the bane of a heart healthy diet. Others, however, regard fats as relatively harmless – and say that the notion that “Fats are bad for you” is little more than a widely-circulated myth.

So what’s the reality of the situation? Are fatty foods indeed dangerous delectables, as some claim, or are they actually dietary scapegoats and unfairly vilified?

The answer, it turns out, doesn’t fall squarely into either of these camps (note that you can see how fats are affecting your personal well-being with the Everlywell Heart Health Test). This is to be expected, of course, since the reality of human health and biology can’t always be captured by media sound bites and catchy book titles.

In short, the scientific evidence suggests that whether or not fat is bad for you depends on the type of fat under consideration – and there are 3 main kinds of fat: unsaturated fats, saturated fats, and trans fats. Let’s explore each of these in a bit more depth.

Unsaturated Fats

Ever munched on a handful of nuts – or draped a plate of salad with rich layers of olive oil? If so, you were consuming unsaturated fats. Unsaturated fats – commonly found in plant-based foods, as well as fish – are one of the 3 main types of dietary fat.

By and large, unsaturated fats are healthy for the body. For example, an unsaturated fat known as omega-3 can provide a whole host of health benefits – protecting your heart and improving cognition, for example.

Other kinds of unsaturated fat are likewise an important part of a nutritious diet – which is why some refer to unsaturated fats as “the good fat.” This is certainly an appropriate moniker for this type of fat, as much scientific research has shown that unsaturated fats contribute to good health in a number of ways. Clinical trials suggest that unsaturated fats can drop LDL cholesterol levels (high amounts of LDL cholesterol can be quite harmful) – as well as lower blood pressure and reduce the risk of cardiovascular disease.

In short, then, unsaturated fats absolutely deserve a place in a healthy, well-rounded diet. But not all fats do.

Saturated Fats

Found in fast foods and dairy-based desserts like ice cream – as well as many meat and cheese products – saturated fats are a staple ingredient of many culinary delights. Saturated fats also happen to be at the center of much controversy. In the latter half of the 20th century, many scientists and health experts denounced saturated fats as – perhaps – the leading dietary cause of obesity and heart disease. There was some pushback to this idea, with a few mavericks – like Dr. Robert Atkins, creator and popularizer of the Atkins diet – extolling the virtues of saturated-fat-laden meals and blasting, instead, carbohydrate-rich diets.

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So what about today? What does the current research say about saturated fats? While there are conflicting views on just how bad saturated fats are for the body, the bulk of the scientific evidence suggests that replacing saturated fats with unsaturated fats is one the best ways to a healthy, robust heart. That’s one of the reasons why people living in Mediterranean countries are usually at a lower risk of cardiovascular diseases: the traditional Mediterranean diet, consisting of fresh fruit, olive oil, nuts, and fish instead of red meat, is low in saturated fat.

Trans Fats

If there’s any type of fat that’s unequivocally dangerous to your health, it’s trans fatty acids – or trans fats. Many foods that have been fried or baked – like french fries, cakes, and cookies – can contain relatively high amounts of trans fats. Although trans fats can be found in nature – such as in dairy fat – the vast majority of dietary trans fatty acids are created through an industrial method known as hydrogenation.

Why can trans fats be so destructive to health? There are actually quite a number of reasons why. For one, trans fatty acids can elevate levels of LDL cholesterol (the “bad” cholesterol) and drop HDL cholesterol levels (the “good” cholesterol) – thus heightening the risk of heart disease.

And that’s not all, either: trans fatty acids are also thought to lead to higher levels of triglycerides – a significant risk factor for stroke. In fact, so harmful are trans fats that – roughly speaking – there are up to 100,000 premature deaths every year in the United States as a result of heart disease caused by trans fatty acids. Understandably, these destructive attributes of trans fatty acids prompted one group of researchers to state that “Trans fatty intake should be zero.”


The right kind of fat – specifically, unsaturated fat – is essential to a healthy, nutritious diet. Thus not all fats are bad for one’s health. However, there is overwhelming evidence that trans fatty acids are quite dangerous to the body’s well-being, so replacing consumption of trans fatty acids with unsaturated fats is an excellent way you can contribute to your overall health.

You may also want to check up on your cholesterol, lipids, and triglyceride levels with a Cholesterol and Lipids Test to get a clearer picture of your heart health. To do that from the comfort of your home, simply take Everlywell’s easy-to-use Heart Health Test.

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