12 Surprising Foods That Sneak in Trans Fats

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The trouble with trans fat

Trans fat is a type of unsaturated fat that has no known health benefits, according to the World Health Organization (WHO). It exists in two forms—natural and artificial trans fats—explains Gabrielle Gambino, MS, RD, CDN, CNSC, senior clinical nutritionist at NewYork-Presbyterian/Weill Cornell Medical Center.  “Naturally occurring trans-fats, also called cis fatty acids, are created in the guts of certain animals and mainly found in products made by these animals, generally dairy and meat,” she says. “On the other hand, artificial trans fats are man-made by adding hydrogen to unsaturated, liquid vegetable oils, in turn making them more solid at room temperature.” 

There are benefits to this artificial processing—but they aren’t health-related, explains Julia Zumpano, RD, LD, a registered dietician with the Cleveland Clinic’s Center for Human Nutrition. “[Trans fats] are inexpensive, easy to use, last a long time, and provide a desirable taste and texture.” These properties allow food manufacturers to produce cheap, shelf-stable products and restaurants to save costs by reusing frying oil, for example. 

Most research highlights the negative effects of these artificial trans fats. “Chronic intakes of artificial trans fats could alter our cholesterol levels by increasing our LDL levels, altering fat metabolism in the liver, potentially altering our bodies’ ability to process sugar, increasing inflammation, and, lastly, promoting cell damage,” Gambino says. “All of these changes may be linked to an increased risk of developing chronic diseases such as coronary artery disease and diabetes.” 

Research published in 2023 in Progress in Lipid Research spells the dangers out clearly. It says that excessive intake of trans fats (defined as more than just 1% of total calorie intake) increases the risk of heart disease by 21% and the risk of all-cause death by 28%. 

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Is trans fat OK in moderation?

“No, we want to avoid artificial trans fat completely,” says Zumpano. She explains that most of us are getting small amounts of naturally occurring trans fat from animal products—and if we choose lean versions of these foods, the amount of trans fat is minimal. 

Research is ongoing on the health effects of naturally occurring trans fat. Gambino says that some studies show no difference: Both forms of trans fats seem to alter cholesterol levels negatively. One potential exception to the rule is conjugated linoleic acid (CLA), a natural trans fatty acid found in grass-fed animal products such as cheese and yogurt. “One large study described an association between intake of cheese from grass-fed cows and lower incidence of heart attack,” Gambino says. But that doesn’t mean you need to seek CLA out in your diet: It’s not an essential nutrient we need and it’s already found in many foods. 

Are trans fats banned?

In 2015, the US Food and Drug Administration (FDA) came out with a new position statement regarding partially hydrogenated oils (PHOs)—the major source of artificial trans fat in our foods—stating that these oils are no longer on the Generally Recognized as Safe (GRAS) list, Gambino explains. “Any company previously including PHOs in its products needed to reformulate recipes and omit trans fats by the year 2021.” 

Another revision of the FDA’s statement came out in 2023. “In the original regulations, there were a few items that were still allowed to include PHOs—items like peanut butter, canned tunas, rapeseed oil, margarine, shortening, and bread products,” she says. These products are now similarly regulated, banning PHOs in their ingredients.

But—and this is a big but—products with PHOs absolutely still exist. “The ban allows foods that contain 0.5 grams of trans fat or less to be labeled as having zero grams of trans fat,” Zumpano says. “Although it seems minimal, that amount can add up, especially if you are consuming greater than one serving.” 

Sneaky sources of trans fats

“Anything with ‘partially hydrogenated oils’ in its ingredients list will have ‘hidden’ trans fats,” Gambino says. “Fast-food companies provide nutrition facts on their websites, which can be helpful.” In general, you want to avoid fast food, convenience store or gas station food, and processed foods as much as you can—but our experts point to some everyday products you might not realize have trans fats lurking within their ingredients. 

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Coffee creamer

Gambino says non-dairy coffee creamers tend to contain trans fat. And just under half a gram of trans fat per serving can quickly multiply, as the average American drinks about three cups of coffee per day, according to the National Coffee Association. “Try oat milk or almond-based creamers,” Gambino recommends. “Many reformulated, plant-based alternative products tend to be less prone to trans fat ingredients than their original counterparts.” (Or, you can try making coffee creamer at home!) 

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Peanut butter

Some commercial brands of peanut butter may contain partially hydrogenated oils to achieve a longer shelf life and creamy texture. But that doesn’t mean you should avoid peanut butter altogether—it’s a great source of protein, fiber, and nutrients like B6 and potassium. Zumpano recommends reaching for “natural” peanut butter, which contains just one ingredient: peanuts (and sometimes a pinch of salt). 

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Popcorn

Though often marketed as healthy, Zumpano says microwavable popcorn generally contains trans fat. Because the FDA guidelines allow 0.5 grams of trans fat per serving, this can add up quickly. “For instance, a serving size may be one cup of microwave popcorn, and you may eat four cups, therefore consuming two grams of trans fat.” One workaround for your next movie night: “Just do the old-fashioned air pop or use an actual oil to pop the kernels in,” says Dawn Napoli, RD, a registered dietitian with the University of Florida Health Cancer Center at Orlando Health. 

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Frozen pizza

Trans fat is lurking in the dough of many frozen pizzas, with about 0.3 grams in just one slice. Napoli suggests avoiding the risk by making your own pie at home. “Then you know what’s in the dough, and you can look at the cheese ingredients and other toppings,” says Napoli. “If you’re ordering out, ask what type of fat they’re using. If they say margarine or shortening, you are likely getting trans fat.” 

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Packaged baked goods

Packaged baked goods such as pies and pie crusts, pastries, cookie dough, and packaged frosting are notorious for hiding trans fats in their ingredients, according to Zumpano. “As with pizza, ask bakeries whether they use margarine or shortening,” Napoli advises. 

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Margarine

“I always recommend using butter versus margarine,” Napoli says. To create the creamy spread, liquid vegetable oils are blasted with hydrogen—and the more solid the margarine is, the more it’s been hydrogenated. “If you’re going to use margarine, try to use the more liquid ones,” Napoli says. “Pumps, sprays, or tubs are better than the stick.”

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Protein bars

While it’s best to get your protein from whole foods, protein bars can be a good option in a pinch. But reading labels is essential—many energy and protein bars are loaded with sugar, while some may also sneak in some trans fats, according to Zumpano. Check out our list of nutritionists’ favorite energy bars, or try these dietician-created protein bar recipes you can make at home. 

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Granola

Granola and granola bars may still contain some amounts of trans fats, Gambino says. And that includes packaged cereal bars and breakfast bars. Make sure to scan labels for any mention of “partially hydrogenated.” 

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Tortillas

Not all soft-flour tortillas contain trans fat—but some brands still use shortening in their manufacturing process to boost the product’s shelf life. If in doubt, corn tortillas are generally the healthier option.

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Crackers

Most crackers and snack mixes have little nutritional value—but you might not realize just how many trans fats get packed into these products. In general, “Stay away from processed foods as much as you can,” urges Gambino. Most contain partially hydrogenated oils, added colors and flavors, and sugars. And a rule of thumb: The more artificial the flavor, the worse it is for you.

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Salad dressings

“Salad may be healthy, but watch out for the dressing,” Gambino says. Some store-bought dressings may contain hydrogenated oils for a smooth consistency and extended shelf life. The best bet is to make your own dressing at home—which can be as simple as olive oil and vinegar. 

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Frozen yogurt

Dairy products are a source of naturally occurring trans fat—but some frozen yogurts also contain partially hydrogenated oils, Gambino says. However, in light of FDA guidelines and public health warnings, some brands are making efforts to remove PHOs from their frozen yogurt products. In 2016, some of Pinkberry’s frozen yogurt flavors included PHOs—but as of 2024, the formulations are trans-fat free. Still, toppings such as sprinkles and birthday cake crumbles do contain trans fats. 

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