Good Fats vs Bad Fats — Here’s The Skinny on Dietary Fat

Good Fats vs Bad Fats

In today’s world, it’s hard to know what to believe is true. This is especially true when it comes to what you should and should not eat. One of the foods that has been particularly confusing due to conflicting research and advice is fat, specifically good fats vs bad fats.

Fat often gets a bad name because we tend to generalize all fats into one. With this, we uphold fears that consuming any fat will lead to gaining body fat and increasing bad cholesterol. But the fact of the matter is not all fats are the same. There are many different types of fat that can be considered either good or bad.

Why Did Fat Become Vilified?

Now it’s not uncommon to have undesirable or sour feelings and thoughts about fat. At one time, it was thought that all fat was actually bad (forget the good fats vs bad fats debate). This all began in the 1930s when coronary heart disease became the leading cause of death in the United States. However, it wasn’t until after WWII when Americans began realizing there was a spike in heart disease and preventative action needed to be taken.

Current evidence at the time pointed to saturated fat as a culprit, as it led to an increase in LDL or “bad” cholesterol, which then led to the development of heart disease and obesity. As a preventative action, in the 1980s, the Dietary Guidelines for Americans were released, recommending reducing dietary fat intake, specifically saturated fats. 1

Now I’m sure when these guidelines came out, the intention was that fat in the diet be replaced with whole grains, fruit, and vegetables, but what came across to the public was a simpler, more straight-forward idea: Fat was bad and carbs were good. With this in mind, there was a surge in low-fat foods hitting the market, but with these low-fat foods came a lot of added sugar, carbs, trans fat, and even more health concerns for Americans.

Luckily now, there is a surplus of evidence supporting the intake of healthy dietary fats as we now realize fat is essential and beneficial to the body. Fat is one of three macronutrients our bodies require and it’s critical for supporting cognitive health; absorbing fat-soluble vitamins such as A, D, E, and K; providing energy, balancing hormones, and maintaining fundamental processes in the body.

What Makes Each Fat Type Different?

There are three main categories of fat. These are:

  • unsaturated fats
  • saturated fats
  • trans fats.

What distinguishes the differences between these boils down to the number of double bonds in the fatty-acid chain. Saturated fatty acids lack double bonds between the individual carbon atoms, whereas unsaturated fatty acids have at least one double bond in the fatty acid chain. Although this characteristically may not seem like it matters that much, it makes a big difference on how these fats act in the body.

This then brings us to the third type of fat: trans fat. Trans fat is the oddball when it comes to its structure because it is a fatty acid which has a double bond but doesn’t have the expected bent structure. This creates an issue because the body has a hard time reacting with this type of fatty structure. As a result, trans fats build up in the body and can cause a lot of damage.

Good Fats vs Bad Fats: Here’s the Skinny

So, how do you know what kind of fat is good and what kind of fat is bad? When thinking more broadly, unsaturated fats are typically labeled as good fats, saturated fats are okay, and trans fats are labeled as bad. But when thinking about what fats are good vs. bad, there is a lot more that needs to be considered.

Good Fats vs Bad Fats

Unsaturated Fats

Unsaturated fats can be broken down even further into monounsaturated and polyunsaturated fats.

Monounsaturated fats have a single carbon-to-carbon double bond. The result is that it has minus two hydrogen atoms than a saturated fat and a bend at the double bond. Monounsaturated fats can have healthful benefits such as helping decrease the risk for heart disease by reducing blood pressure and triglycerides and also reducing inflammation. 2,3,4 Some good sources of monounsaturated fats include olive oil, avocado, and nuts.

Polyunsaturated fats can also be broken down into two categories: omega-3 fatty acids and omega-6 fatty acids. These fats have two or more double bonds in their carbon chain and are essential fats for the body to function. However, polyunsaturated fat cannot be produced by the body, so you must consume them from the foods you eat.

There are many types of omega-3 fatty acids, but the most common are EPA, DHA, and ALA. These types of fat have been proven to be vital for blood clotting; supporting heart, brain, and mental health; and decreasing inflammation that can contribute to a number of chronic diseases. 5,6,7,8 A few good sources of omega-3s are flaxseeds and fatty fish such as tuna and salmon.

Omega-6 fatty acids are also essential and can be beneficial. The most common omega-6 fat is linoleic acid, which can be converted into acid (ARA). Omega-6 is considered to be pro-inflammatory, which can be good in small amounts. However, the western diet contains more omega-6 fatty acids than necessary, which can put us at risk for various chronic conditions. 9,10 As a result, most people should significantly reduce their omega-6 intake and in turn try to replace it with healthier alternatives. Omega-6 fatty acids can be found in sunflower, safflower, and corn oils, for example.

Saturated Fats

Saturated fat, on the other hand, has been a topic of debate whether or not it is truly good for us. This is because saturated fat has long been considered a less desirable type of fat. It seemingly affects cholesterol levels and heart disease. This idea that saturated fat consumption led to heart disease followed the diet-heart hypothesis, which has now been discredited. This is because recent research suggests it is not as harmful as once thought. 11,12

In fact, it’s now widely accepted that saturated fat is not associated with heart disease or other adverse health outcomes. Saturated fats can be beneficial in boosting metabolism and increasing energy. Common sources of saturated fat are coconut oil, whole-fat dairy, and red meat.

Trans Fats


Finally, we have trans fat. Trans fat is the worst kind of fat because not only does it raise bad LDL cholesterol but also lowers good HDL levels. Artificial trans fats can also create inflammation, which is linked to heart disease and other chronic conditions and contributes to insulin resistance, which increases your risk of developing Type 2 diabetes. Fortunately, artificial trans fat has now been banned by the Food and Drug Administration.

Good Fats vs Bad Fats: A Wrap-Up

With all this in mind, I think it’s safe to say that the rumor that fat should be avoided is no longer intact. But there is a clear difference between good fats vs bad fats.

It is recommended that daily fat intake be in the range of 20 – 35% of total calories. However, this range can vary depending on your lifestyle and personal nutrition needs. Regardless, it is important to remember that dietary fat is essential as your body needs to perform some of its most fundamental functions.

We should no longer fear fat but rather embrace healthy fat in the diet and turn to healthy fat alternatives such as omega-3s to support healthy living.

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