Trans Fats

We know research shows that reducing trans fat in the American diet helps reduce risk of heart disease, but how and why? Let's try to clear up the confusion about trans fats.

What are trans fats?

There are two broad types of trans fats found in foods: naturally-occurring and artificial trans fats. Naturally-occurring trans fats are produced in the gut of some animals and foods made from these animals (e.g., milk and meat products) may contain small quantities of these fats. Artificial trans fats (or trans fatty acids) are created in an industrial process that adds hydrogen to liquid vegetable oils to make them more solid.

In the past, the primary dietary source for trans fats in processed food was from “partially hydrogenated oils (PHOs)." In 2015 the U.S. Food and Drug Administration (FDA) made the determination that partially hydrogenated oils are no longer Generally Recognized as Safe (GRAS) in human food and are no longer able to be added to foods.

How do trans fats affect my health?  

Trans fats raise your bad (LDL) cholesterol levels and lower your good (HDL) cholesterol levels. Eating trans fats increases your risk of developing heart disease and stroke. It’s also associated with a higher risk of developing type 2 diabetes. 

Why did trans fats become so popular if they have such bad health effects? 

Before 1990, very little was known about how trans fat can harm your health. In the 1990s, research began identifying the adverse health effects of trans fats. Based on these findings, FDA instituted labeling regulations for phasing out use of PHOs. As of January 1, 2021, any use of trans fats from PHOs was no longer allowed, and trans fat consumption has decreased in the U.S. in recent decades. 

Are there naturally occurring trans fats? 

Small amounts of trans fats occur naturally in some meat and dairy products, including beef, lamb and butterfat. You can determine the amount of trans fats in a particular food by looking at the Nutrition Facts label. However, products can be listed as “0 grams of trans fats” if they contain 0 grams to less than 0.5 grams of trans fat per serving. There have not been sufficient studies to determine whether these naturally occurring trans fats have the same bad effects on cholesterol levels as trans fats that have been industrially manufactured. 

Regulating your intake of saturated and trans fats

The American Heart Association recommends that adults who would benefit from lowering LDL cholesterol reduce their intake of trans fat and limit their consumption of saturated fat to 5 to 6% of total calories. 

Here are some ways to achieve that.

• Eat a dietary pattern that emphasizes fruits, vegetables, whole grains, plant-based proteins, low-fat/fat-free dairy products, poultry, fish and nuts. Also limit fatty meat, sodium and sugary foods and beverages.
• Use naturally occurring, non-hydrogenated vegetable oils such as canola, safflower, sunflower or olive oil most often.
• Look for processed foods made with non-hydrogenated oil rather than partially hydrogenated or hydrogenated vegetable oils or saturated fat.
• Use soft margarine as a substitute for butter, and choose soft margarines (liquid or tub varieties) over harder stick forms. Look for “0 g trans fat” on the Nutrition Facts label and no hydrogenated oils in the ingredients list.
• Doughnuts, cookies, crackers, muffins, pies and cakes are examples of foods that may contain trans fat. Limit how frequently you eat them.
• Limit commercially fried foods and baked goods made with shortening or partially hydrogenated vegetable oils. Not only are these foods very high in fat, but that fat is also likely to be trans fat.
• Read the full American Heart Association Diet and Lifestyle Recommendations.