Just the facts. From the experts.

What are trans fats anyway? The American Heart Association says, “Trans fats (or trans fatty acids) are created in an industrial process that adds hydrogen to liquid vegetable oils to make them more solid.” They are used because they are easy to handle, inexpensive to produce, they have a great shelf life and they create a great taste and texture as a food ingredient.

For more information on the science behind trans fats, Best Food Facts reached out to sports nutritionist Dr. Liz Applegate and food scientist and registered dietitian Dr. Ruth MacDonald.


Dr. Liz ApplegateSenior Lecturer, Department of Nutrition and Director of Sports Nutrition, Intercollegiate Athletics, University of California – Davis


Dr. Ruth MacDonaldChair and Professor of the Department of Food Science & Human Nutrition, Iowa State University.



Scientifically speaking, what are trans fats?

Dr. Applegate: "Trans" refers to the configuration of the chemical bonds within the fat. Artificially-produced trans fats are found in partially-hydrogenated and hydrogenated oils. Small amounts of trans fats are naturally occurring in foods like butter and beef, while the remainder come from hydrogenated vegetable oils, such as margarine and shortening, that have been chemically produced.

Dr. MacDonald: Fatty acids are strings of carbon molecules connected together. A carbon molecule can bind to four other molecules – so typically in the chain each carbon is attached to two hydrogen molecules (and two carbons). In some fats, one hydrogen is removed and the electrons form a double bond across the carbon-carbon link. This creates a two-sided molecule around the double bond (one side with a carbon and the other with the carbon chain) that allows the entire chain to bend in space. When the carbon chains are in the same plane, opposite of the hydrogens, the result is a cis-fatty acid. When the carbon chains are opposite each other this is called a trans-fatty acid. In nature, the majority of fatty acids are cis, and the enzyme machinery of our bodies are designed to use and degrade cis fatty acids. Hence, trans fatty acids are not easily degraded in the body.

How can trans fats be removed from food products?

Dr. Applegate: Trans fats have different melting points than fully saturated oils, so trans fats can be removed based on their melting points.


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