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

Natural sources of trans fats are found in meat, milk, butter and cheese from ruminant animals — cows, sheep, goats — and are considered by some in the MAHA movement to be healthy. —Sandee Lamotte, CNN Money, 20 Jan. 2026

To lower your risk, your healthcare team may recommend limiting your intake of saturated and trans fats. —Carrie Madormo, Verywell Health, 12 Jan. 2026

The new guidelines emphasize food items historically recommended in moderation, specifically red meat, whole-fat dairy and several types of fats, including trans fats. —Mary Walrath-Holdridge, USA Today, 12 Jan. 2026

The cupcakes were made fresh in small batches throughout the day and contained no preservatives, trans fats or artificial flavors, according to the company. —Pat Maio, Oc Register, 31 Dec. 2025

Word History

First Known Use

1974, in the meaning defined above

Rhymes for trans fat

• begat
• bobcat
• chitchat
• doormat
• ducat
• eclat
• format
• hazmat
• muskrat
• nonfat
• polecat
• thereat

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