Oils and Fats: Seed Oils, Palm Oil, Trans Fat and More
Last reviewed October 18, 2026 · How we grade evidence
In plain words: The one fat with clear proof of harm is artificial trans fat from partially hydrogenated oil, and it's now banned in US food. Seed oils like soybean and canola aren't shown to cause inflammation. Coconut and palm oil raise LDL cholesterol more than liquid oils. For most families, the type of food (fried and packaged vs home-cooked) matters more than which oil is in it.
Fats are where online advice and research disagree the most. Seed oils get blamed for inflammation, yet human trials don't show it,1 and large reviews favor swapping saturated fats for unsaturated ones.2 Meanwhile coconut oil, often sold as a superfood, raises LDL cholesterol more than vegetable oils in trials.3
The clearest story is trans fat: it's linked with higher heart disease and death,4 and FDA removed partially hydrogenated oils from the food supply by 2021.5
At a glance
| Ingredient | Our take | Evidence | US products* |
|---|---|---|---|
| Partially Hydrogenated Oils (Trans Fat) | Clearly raises heart risk. Banned in US food; put it back if you see it. | Strong | 8,400 |
| Brominated Vegetable Oil (BVO) | No longer allowed in US food since 2024. Any product listing it is old stock. | Limited | 619 |
| Palm Oil | Raises LDL more than liquid oils; refining contaminants now limited in the EU. | Moderate | 53,555 |
| Coconut Oil | Raises LDL more than vegetable oils. Fine in moderation, not a health food. | Moderate | 16,808 |
| Seed Oils (Soybean, Canola, Corn and More) | Not shown to cause inflammation. Fine, even helpful, in place of butter-type fats. | Moderate | 130,363 |
| MCT Oil | Small weight effect (about a pound). Stomach upset is common. | Moderate | 1,842 |
| Interesterified Fats | Contain no trans fat. Mixed small trials; rarely named on labels. | Limited | 1,493 |
Number of US packaged foods in USDA's Branded Foods database whose ingredient list names it. See each page for details.
A simple oil plan for families
- Put back anything that says "partially hydrogenated."
- For everyday cooking, use liquid oils you like: olive, canola, avocado or peanut.
- Use butter, coconut oil and ghee for flavor, not as health foods.
- Fry less often, don't reuse frying oil many times, and run the range hood.
- Cut back on chips, fried fast food and packaged baked goods. That changes more than any oil swap.
Frequently asked questions
What is the healthiest cooking oil?
Liquid oils like olive and canola have the best evidence for heart health. Use what fits your cooking and budget.
Are seed oils toxic?
No. Human trials don't show they cause inflammation, and most heart research finds them neutral or helpful in place of saturated fat.
What fats should I avoid?
Partially hydrogenated oils (trans fat). Limit coconut and palm oil if you're watching LDL cholesterol.
Sources
- Effect of dietary linoleic acid on markers of inflammation in healthy persons: a systematic review of randomized controlled trials. J Acad Nutr Diet, 2012. PubMed 22889633 · doi:10.1016/j.jand.2012.03.029
- Reduction in saturated fat intake for cardiovascular disease (Cochrane). Cochrane Database Syst Rev, 2020. PubMed 32827219 · doi:10.1002/14651858.CD011737.pub3
- The Effect of Coconut Oil Consumption on Cardiovascular Risk Factors: A Systematic Review and Meta-Analysis of Clinical Trials. Circulation, 2020. PubMed 31928080 · doi:10.1161/CIRCULATIONAHA.119.043052
- Intake of saturated and trans unsaturated fatty acids and risk of all cause mortality, cardiovascular disease, and type 2 diabetes: systematic review and meta-analysis of observational studies. BMJ (Clinical research ed.), 2015. PubMed 26268692 · doi:10.1136/bmj.h3978
- FDA: Trans Fat. 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].