Myth or fact

Trans fat is gone, so you can ignore it

Short answerSort of

By GyroscopeUpdated November 14, 20267 sources

Sort of. Partially hydrogenated oils, the source of almost all artificial trans fat, have been out of US food since 2018 to 2021. A little trans fat still occurs naturally in milk, butter, cheese and meat, and a label can call anything under half a gram a serving zero.

Trans fat spent years as the fat to fear, and checking the label for it became a habit for a lot of people. Then the FDA took partially hydrogenated oil out of the food supply, and the word mostly disappeared from the news. People reasonably concluded it was gone.

The artificial kind is gone. The natural kind never left, and the label is built in a way that hides small amounts.

What did the FDA do?

In 2015 the FDA found that partially hydrogenated oils were no longer “generally recognized as safe”. For most uses, June 18, 2018 was the last date manufacturers could add them to food. The FDA gave products already made until January 1, 2021 to work their way out of the supply. In the agency’s words, removing them “is estimated to be preventing thousands of heart attacks and deaths each year”.

The FDA’s page is clear about what it didn’t touch. “Trans fat also occurs naturally in food products from ruminant animals (e.g., milk, butter, cheese, meat products),” and its actions “have not affected these natural sources”.

How much natural trans fat is in food?

There isn’t much, but it’s in foods people eat every day. Here are three, from the USDA’s tables.

In each food the saturated fat is ten times or more the trans fat. That’s why we’d watch the saturated fat and let the trans fat come along with it. The National Academies recommend keeping trans fat “as low as possible without compromising the nutritional adequacy of the diet”, and there’s no Daily Value for it on the label.

Why can a label say 0 g?

US labeling law rounds trans fat to the nearest half gram. In the words of the rule, “If the serving contains less than 0.5 gram, the content, when declared, shall be expressed as zero.” A tablespoon of butter has about 0.46 g, so a butter label can show 0 g of trans fat.

This was a bigger problem when partially hydrogenated oil was in packaged foods. A snack that held 0.4 g a serving could say zero, and three servings brought more than a gram. With those oils gone, the rounding now mostly hides the natural trans fat in dairy and meat.

Can heating oil make trans fat?

It can, a little. In one 2018 lab test, trans fat rose slightly in the oils after hours of heating, along with many other changes. The bigger worry with long frying is the breakdown products that build up as the oil is reused. Oils in the kitchen covers which oils hold up best, and Trans fat tells the whole story, from Crisco in 1911 to the ban.