Fat is a rather polarizing macronutrient. In the 1980s and 1990s, low-fat and fat-free diets were all the rage after a large body of evidence was amassed suggesting a link between high-fat diets and the risk of cardiovascular disease and all risk mortality.
In subsequent years, with further and more specific research, it seemed that the potential health dangers associated with consuming fatty foods were really only demonstrable for specific types of fats, namely trans fats, and potentially saturated fats.
On the other hand, polyunsaturated fats, monounsaturated fats, and omega-3 fatty acids (a specific subtype of polyunsaturated fats) were not only deemed to be harmless to human health but actually beneficial for the heart and brain, among other health benefits.
Still, there is a lot of confusion surrounding types of dietary fat, particularly trans fat vs saturated fat. Are both trans fat and saturated fat bad for your health? What is the difference between trans fat vs saturated fat? What types of foods contain saturated fat vs trans fat?
In this article, we will discuss the differences between trans fat vs saturated fat, providing guidance to help you tailor a heart-healthy diet that contains “good” or healthy fats and avoids “bad” or unhealthy fats.
More specifically, we will cover:
- Is Eating Fat Bad?
- Trans Fat vs Saturated Fat
- What Is Saturated Fat?
- What Is Trans Fat?
Let’s jump in!
Is Eating Fat Bad?
Although dietary fat tends to get a bad rap, there are different types of fats, and not all of them are bad for your health.
Certain types of fats, specifically polyunsaturated fats (including omega-3 fatty acids) and monounsaturated fats, can actually provide a cardioprotective effect in the body by reducing blood pressure and improving circulation.
Moreover, omega-3 fatty acids and omega-6 fatty acids are considered essential fats because the body cannot synthesize them endogenously. It is important to remember that dietary fats provide more than calories (energy).
Fats are necessary for helping absorb fat-soluble vitamins (vitamins A, D, E, and K), insulation, synthesizing hormones, forming cell membranes, and manufacturing cholesterol, among other functions.
Polyunsaturated and monounsaturated fats are found in healthy foods such as fatty fish (salmon, tuna, mackerel, sardines, etc.), avocados, olive oil and olives, flaxseed oil, nuts, and seeds.
However, there are also types of fat that, when eaten in excess, can be deleterious to cardiovascular health.
When comparing trans fat vs saturated fat, trans fat is nearly universally considered to be more problematic.
The potential health risk posed by diets high in trans fat has spurred the Food and Drug Administration (FDA) to remove these types of fats from the manufacturing process and to clearly make a note on the ingredients label or product packaging that a food contains trans fat.
Trans fat vs Saturated Fat
The two types of healthy fats—polyunsaturated fats and monounsaturated fats—are liquid at room temperature because there is at least one double bond between the carbon atoms that form the backbone of the triglyceride molecule.
In contrast, the chemical structure of trans fat and saturated fats makes them solid at room temperature (think butter, lard, and margarine versus oils).
The research surrounding the adverse health effects of saturated fat is less conclusive than those regarding trans fats. There is evidence to suggest that replacing saturated fat with foods that contain unsaturated fats or carbohydrates reduces the risk of cardiovascular disease.
However, although it was once thought that diets high in saturated fat were clearly associated with an increased risk of heart disease and all-cause mortality, subsequent research has been less clear, with some research even indicating that certain saturated fats—such as those found in coconut oil—may be healthy for the heart.
In general, while nearly all nutrition experts recommend unilaterally removing all trans fats from the body, some amount of saturated fat can and should, be included in the diet. Furthermore, even some of the foods packed with natural healthy fats, such as salmon, contain some saturated fat.
What is Saturated Fat?
Saturated fats differ in chemical structure from polyunsaturated fats and monounsaturated fats in that all of the carbon atoms that form the backbone of the constituent triglyceride molecules have single bonds between them, with all other bonds made with hydrogen atoms.
With monounsaturated fats, there is one double bond between carbon atoms, and with polyunsaturated fats, there are multiple carbon atoms that have double bonds between them instead of single bonds.
The greater the number of double bonds, the more fluid or bendable the fat molecule is. This changes how the fat behaves both in and out of the body. This is why, for example, unsaturated fats are liquid at room temperature.
Saturated fat is primarily found in animal-based foods such as red meat, poultry skin, egg yolks, pork, and full-fat dairy. Because butter is high in saturated fat, baked goods, and fried foods are also high in saturated fat. There are some plant-based sources of saturated fat, namely coconut oil, palm oil, and palm kernel oil.
According to Harvard Health, the primary sources of saturated fat in the United States are pizza, cheese, whole, and reduced-fat milk, butter, ice cream, cookies, and fast food dishes.
Given the conflicting evidence and the fair amount of research suggesting that saturated fats are harmful when consumed excessively, the Dietary Guidelines for Americans recommends limiting your saturated fat to no more than 10% of your total calories daily.
For example, if you are consuming 2000 calories a day, you should be eating no more than 200 calories of saturated fat. Because there are 9 calories per gram of fat, this means you should limit your saturated fat intake to a maximum of 22 grams per day.
Moreover, the American Heart Association recommends that your saturated fat intake should constitute no more than 7% of your total daily calories.
What Is Trans Fat?
Trans fats are also known as trans fatty acids or partially-hydrogenated oils. When comparing saturated fat vs trans fat, trans fats are definitely more harmful to your health.
Perhaps surprisingly, trans fats are not derived from saturated fats but rather unsaturated fats, which are normally considered to be healthy. A small minority of trans fats are naturally produced in the stomachs of ruminant animals (such as cows and sheep), so these trans fats can be found in certain meat and full-fat dairy products.
However, the vast majority of trans fats, and those that are considered to be the most harmful to your health, are considered industrial oils because they are man-made using a process termed hydrogenation.
When you look at the ingredients label on a food product, which says “partially-hydrogenated soybean oil,” “partially-hydrogenated cottonseed oil,” or some other form of hydrogenated oil, it is an indication that the product contains trans fats.
The hydrogenation process converts a liquid vegetable oil (unsaturated fat) to a type of fat that is solid at room temperature in order to increase the shelf life and stability of the product.
Although naturally occurring unsaturated fats are healthy, the chemical structure of trans fats differs in a way that makes them particularly harmful to cardiovascular health.
Studies have found that diets high in trans fats increase levels of LDL (“bad“) cholesterol, decrease levels of HDL (“good”) cholesterol, and can increase the risk of certain diseases such as type 2 diabetes, heart disease, and stroke.
Although the FDA has strict regulations about how much trans fat can be contained in a food product per serving, trace amounts of trans fats can still be found in packaged and processed foods such as packaged snack cakes and muffins, biscuits, donuts, pie crusts, margarine, vegetable shortening, frozen pizza, and packaged pastries.
Ultimately, in the United States, foods are not supposed to contain more than 0.5 g of trans fat per serving, which then gets rounded down to 0 grams of trans fats on the labeling.
Therefore, some packaged foods claim to have no trans fats, but if you carefully investigate the label, you may find that there are sources of trans fats used in the recipe that will contribute some amount of trans fat to the food product.
It is also important to note that other countries do not necessarily have the same strict regulations found in the United States, so packaged foods eaten abroad may contain more trans fats.
Overall, when it comes to trans fat vs saturated fats, there are similarities in how either in excess can be harmful to your health. That said, the evidence surrounding the danger of saturated fats is mixed at best, whereas trans fats are known to be deleterious to your health.
Avoiding all trans fats is key, and limiting saturated fats to 7 to 10% of your daily total caloric intake is ideal for heart health.
What about protein, another one of the macronutrients? Is it possible for one to eat too much protein? For more information on this topic, you can check out our article Can You Eat Too Much Protein? 8 Signs You Are Overdoing It.