Interesterified Fats
Last reviewed October 18, 2026 · Evidence strength: Limited · How we grade evidence
In plain words: Interesterified fats are oils rearranged to act like solid fats after trans fats were banned. One older study raised concerns, but better trials since haven't confirmed harm, and they contain no trans fat. They rarely show up by name on labels anyway.
Also listed on labels as: Interesterified soybean oil, Interesterified vegetable oil, Interesterified fat
What is it, and why is it in food?
Interesterification shuffles the fatty acids in a fat to change how it melts, often blending a liquid oil with a fully hydrogenated one. It's used in shortenings, spreads, baked goods and frozen dough. US labels don't have to say "interesterified."
What does the science say?
| The popular claim | "Interesterified fats are the new trans fats and raise blood sugar and harm cholesterol." (Common on wellness sites; none of the five experts we reviewed made it.) |
| Our verdict on that claim | Not supported |
| Evidence strength | Limited: a few small trials pointing different ways. |
| Kinds of studies | Small randomized trials |
- Concern: A small 2007 trial (30 people, 4 weeks) found an interesterified fat raised fasting blood sugar about 20% and worsened the LDL/HDL ratio compared with palm olein.1
- Reassurance: A 2018 trial found no effect on insulin resistance,2 and a 2024 trial found no heart-and-metabolism differences with an interesterified spread.3
What do regulators say?
- US and EU: a permitted processing method with no special labeling.
Who should be careful?
- No group has shown harm.
How common is it in US foods?
In our check of USDA's Branded Foods database, 1,493 of 438,129 US packaged foods with an ingredient list name an interesterified fat (about 0.3%, or roughly 1 in 293).4 It shows up most often in: cakes, cupcakes, snack cakes (317); cookies & biscuits (293); mexican dinner mixes (291); prepared wraps and burittos (70); ice cream & frozen yogurt (68). That's only products that name it; many more likely use it under "vegetable oil" or "fully hydrogenated oil." These are label records companies sent to USDA, mostly in 2021 to 2023, so some products have changed since. Counts come from a text match of ingredient lists and are approximate.
Swaps and tips for families
- No specific swap needed. Fewer packaged baked goods cuts these along with many other additives.
Beyond the plate: related non-food exposures
None notable.
Frequently asked questions
Are interesterified fats trans fats?
No. They contain no trans fat.
Are interesterified fats bad for you?
One small 2007 study raised concerns, but later trials didn't confirm harm. The evidence is limited and mixed.
How can I tell if a food has interesterified fat?
Often you can't; US labels don't have to say so. Some list "interesterified soybean oil."
Related guides
Sources
Every source below was checked against PubMed, the publisher or the official page by our research team in October 2026.
- Stearic acid-rich interesterified fat and trans-rich fat raise the LDL/HDL ratio and plasma glucose relative to palm olein in humans. Nutrition & metabolism, 2007. PubMed 17224066 · doi:10.1186/1743-7075-4-3
- Interesterified Palm Olein (IEPalm) and Interesterified Stearic Acid-Rich Fat Blend (IEStear) Have No Adverse Effects on Insulin Resistance: A Randomized Control Trial. Nutrients, 2018. PubMed 30126103 · doi:10.3390/nu10081112
- Postprandial lipid and vascular responses following consumption of a commercially-relevant interesterified palmitic acid-rich spread in comparison to functionally-equivalent non-interesterified spread and spreadable butter: a randomised controlled trial in healthy adults. Food & function, 2024. PubMed 38380649 · doi:10.1039/d3fo05324e
- FoodData Central, Branded Foods dataset (release 2026-04-30). U.S. Department of Agriculture, Agricultural Research Service, 2026. Link
This guide is for general education. It is not medical advice and does not replace advice from your doctor, pediatrician, allergist or registered dietitian. If you think you or your child reacted to a food, talk to a health professional. Research changes; we review these pages when new evidence or rules come out. Last reviewed October 18, 2026. Spotted an error? Email [email protected].