trans fat

noun

variants or trans-fat

ˈtran(t)s-ˈfat 

ˈtranz-

plural trans fats or trans-fats

: an unsaturated fat that contains a trans-fatty acid molecule which has a trans arrangement of double bonds in its hydrocarbon chain and that either occurs naturally in the meat and milk of ruminant animals (such as cows and sheep) or is manufactured by hydrogenating vegetable oil to create a fat (such as margarine or shortening) that is solid at room temperature

The trans fats to watch for are the ones artificially produced and placed in prepackaged foods or commercially prepared deep-fried foods. These trans fats are introduced during cooking or during the manufacturing process to help extend a product's shelf life. They also help some foods taste more satisfying.

—Jennifer Moll

… if you are not minding your intake of another harmful fat called trans-fat, you might still be increasing your risk of heart disease. Indeed, whereas saturated fat raises the body's level of bad "LDL" cholesterol, trans-fat packs a double whammy by also reducing the good "HDL" cholesterol that protects against heart disease …

—Anne Tergesen

compare saturated fat

Examples of trans fat in a Sentence

Recent Examples on the Web

Each time an oil is reused for frying, its trans fat content increases, a study in the journal Food Chemistry found. —Sheah Rarback, Miami Herald, 6 Feb. 2025

These fats are better for you than saturated and trans fats found in cow's milk. —Jamie Johnson, Verywell Health, 3 Feb. 2025

One study found that repeatedly heating canola oil increased the amount of trans fats in the oil by 233%.9 Seed oils repeatedly heated, such as those used to deep fry foods like French fries, are especially prone to oxidation. —Jillian Kubala, Health, 22 Jan. 2025

Foods to avoid with gallbladder issues include: Saturated and trans fats: Eating high amounts of saturated and trans fats may promote gallstones. —Brittany Lubeck, Ms, Rdn, Verywell Health, 16 Jan. 2025

Word History

First Known Use

1974, in the meaning defined above

Medical Definition

trans fat

noun

variants or trans-fat

: an unsaturated fat that contains a trans-fatty acid molecule which has a trans arrangement of double bonds in its hydrocarbon chain and that either occurs naturally in the meat and milk of ruminant animals (such as cows or sheep) or is manufactured by hydrogenating vegetable oil to create a fat (such as margarine or shortening) that is solid at room temperature

Consumption of red meat and trans fats is associated with an increased risk of laparoscopically confirmed endometriosis …

—Linda C. Guidice, The New England Journal of Medicine

Trans fat is created when manufacturers partially hydrogenate liquid oils to make them more solid, more stable, and less greasy-tasting.

—Nutrition Action Health Letter

compare saturated fat