The most effective way to avoid trans fats is to check ingredient lists for the words “partially hydrogenated” before any oil name. Even after the FDA banned partially hydrogenated oils (PHOs) from the U.S. food supply in 2018, trans fats still show up in imported foods, some restaurant cooking, and products sold in countries without bans. Each 2% of daily calories from trans fat is linked to a 23% higher risk of heart disease, making even small amounts worth avoiding.
Why Trans Fats Are Uniquely Harmful
Trans fats hit your cardiovascular system from two directions at once. Like saturated fats, they raise LDL (“bad”) cholesterol. But unlike saturated fats, they also lower HDL (“good”) cholesterol. In controlled feeding studies, people who ate a diet rich in trans fats instead of saturated fats saw their HDL cholesterol drop by about 21%, a significant shift that increases the ratio of harmful to protective cholesterol in the blood. No other common dietary fat does this double damage, which is why health authorities treat trans fats as more dangerous calorie-for-calorie than saturated fat.
How to Spot Trans Fats on Labels
The Nutrition Facts panel is not enough on its own. FDA rules allow manufacturers to print “0 g” of trans fat if a serving contains less than 0.5 grams. That means a product with 0.4 grams per serving can legally say zero. If you eat multiple servings, or several such products in a day, the numbers add up.
Flip the package over and read the ingredient list instead. The key phrase to look for is “partially hydrogenated” followed by any oil (soybean, cottonseed, palm kernel, etc.). If those words appear anywhere in the list, the product contains trans fat regardless of what the nutrition label says. “Fully hydrogenated” oil, by contrast, does not contain trans fat because the process converts all unsaturated bonds, producing a saturated fat rather than a trans fat.
Foods That Still Carry Risk
In the United States, the FDA’s 2018 ban on PHOs (with a final compliance date of January 1, 2021) removed most artificial trans fat from the domestic food supply. But several categories still deserve attention:
- Imported packaged foods. Products manufactured in countries without trans fat regulations may still use PHOs. Check labels on imported crackers, biscuits, snack cakes, and cooking fats.
- Fried street and restaurant food. Globally, fried and baked foods from restaurants and street vendors remain common sources. When traveling or eating at smaller establishments, you have less visibility into what oil is being used.
- Margarine and vegetable shortening. Older-formula stick margarines were a major source. Most brands have reformulated, but discount or imported margarines may not have.
- Vanaspati ghee. This industrially hydrogenated fat, widely used in South Asian cooking, often contains significant trans fat. Look for traditional ghee (made from butter) or check the label for “partially hydrogenated.”
Small amounts of trans fat also occur naturally in meat and dairy from cows, sheep, and goats. The USDA has found limited evidence that these naturally occurring trans fats behave differently from industrial ones at comparable doses, though people typically consume them in much smaller quantities. The FDA ban does not apply to these natural sources.
Choosing Cooking Oils at Home
Cooking at home gives you full control over your fat sources. The oils that work best as PHO replacements are those rich in polyunsaturated or monounsaturated fats. For high-heat cooking like sautéing, stir-frying, or roasting, good choices include avocado, canola, corn, grapeseed, peanut, sunflower, safflower, and regular (light) olive oil. These handle temperatures well and don’t produce trans fats during normal cooking.
Most cooking oils have smoke points between 400°F and 500°F, which is more than adequate for home cooking. You only risk breaking down the oil’s beneficial fatty acids if you heat it to the point of heavy smoking, something that mainly happens during deep frying at very high temperatures. Extra-virgin olive oil has a lower smoke point than refined olive oil, making it better suited for dressings or lower-heat cooking rather than high-temperature frying.
Strategies for Eating Out
In the U.S., major restaurant chains largely reformulated their frying oils after the PHO ban. Most now use blends of canola, soybean, or sunflower oil. Smaller independent restaurants, food trucks, and bakeries may be less consistent, especially those using older recipes that call for shortening in pie crusts, biscuits, or pastry doughs.
If you’re eating in a country that hasn’t banned PHOs, the risk is higher. Fried foods and commercial baked goods are the most common sources internationally. The WHO launched its REPLACE initiative in 2018 with the goal of eliminating industrial trans fat worldwide, and policy coverage has increased more than sixfold since then. But as of 2025, many countries still lack best-practice regulations, leaving consumers responsible for their own choices.
When you can’t verify ingredients, choosing grilled, steamed, or roasted dishes over fried or pastry-based options is the simplest way to reduce your exposure.
A Practical Checklist
- Read ingredient lists, not just Nutrition Facts. The 0.5-gram labeling loophole means “0 g trans fat” on the front doesn’t guarantee zero.
- Search for “partially hydrogenated.” If it’s there, the product contains trans fat.
- Cook with liquid oils. Canola, olive, avocado, and sunflower oils are reliable trans-fat-free options for most cooking methods.
- Be cautious with imported packaged snacks. Crackers, wafer cookies, and flavored chips from countries without bans are common sources.
- Choose soft tub spreads over stick margarine. Softer spreads are less likely to contain PHOs, but still worth checking.
- Limit fried foods when traveling. Street food and small restaurants in countries without regulations often still use partially hydrogenated frying fats.