Trans fats & hydrogenated oils
Partially hydrogenated oils · PHOs · "vegetable shortening"
Industrial fats created by forcing hydrogen into vegetable oil to make it solid and shelf-stable. The FDA banned partially hydrogenated oils in 2018 — but a labeling loophole still lets small amounts through, and "0g trans fat" doesn't always mean zero.
Why we flag them
Trans fats raise LDL ("bad") cholesterol while lowering HDL ("good") cholesterol — a uniquely damaging combination no other fat does. Decades of research linked them to heart disease, stroke, and type 2 diabetes; the WHO estimated they caused roughly 500,000 cardiovascular deaths globally per year before bans took effect. There is no known safe level of artificial trans fat consumption.
In 2018 the FDA officially removed partially hydrogenated oils from the GRAS ("generally recognized as safe") list — effectively a ban. But the labeling rules let manufacturers print "0g trans fat" on products containing up to 0.49g per serving. Eat three servings and you've quietly consumed 1.5g, which adds up across a typical day of processed food.
Where you'll find them
Despite the ban, trace amounts still appear in some products. Look for the ingredient phrases — not just the nutrition panel:
- Microwave popcorn (some brands still use partially hydrogenated oils)
- Frozen pizzas, frozen breakfast sandwiches, frozen pies
- Non-dairy creamers and whipped toppings
- Margarine and "buttery" spreads
- Packaged crackers, cookies, and snack cakes
- Fast-food fried items (some chains still use it abroad)
- Refrigerated biscuit and cinnamon-roll dough
The giveaway phrases on the ingredient list: "partially hydrogenated," "hydrogenated vegetable oil," "shortening," or "mono- and diglycerides" (often a hidden trans-fat source not counted on the label).
What to look for instead
Naturally stable fats deliver the same texture without the cardiovascular hit:
- Butter or ghee — saturated but well-tolerated in moderation
- Coconut oil — solid at room temperature, no hydrogenation
- Cold-pressed olive oil or avocado oil — best for low to medium heat
- Palm fruit oil (sustainable) — semi-solid like shortening, no trans fats
- Whole-fat dairy and unrefined nut butters — replace processed spreads
The cleanest signal is the absence of the words "hydrogenated" or "shortening" anywhere on the ingredient list. USDA Organic certification prohibits PHOs entirely.