Food labels
What is partially hydrogenated oil? How to identify a trans-fat source
Learn why this ingredient matters, where to look for it, and how to use the ingredient list alongside nutrition labels.
Partially hydrogenated oil (PHO) is made by changing liquid oil into a more solid fat. It has historically been a major source of industrially produced trans fat.
Why the ingredient matters
WHO identifies industrially produced trans fat as not part of a healthy diet. In the US, the FDA describes PHOs as having been the primary dietary source of artificial trans fat in processed foods.
Where to look
Check the ingredient list on packaged foods when it is available. Look specifically for “partially hydrogenated oil” rather than assuming a food category or marketing claim tells the whole story.
Make a practical choice
Compare similar products and choose one without PHO where practical. Because rules and product formulas differ by country, always use the label on the item you are buying.
Practical next steps
- 1Check the ingredient lists of packaged snacks, baked goods, spreads, and frozen foods you buy most often.
- 2Compare the ingredient list, nutrition panel, and serving size when alternatives are available.
- 3Save a label photo or product note for repeat purchases rather than relying on a generic food classification.
Frequently asked questions
Can a food photo identify partially hydrogenated oil?
No. It is a formulation detail that requires the ingredient list or manufacturer information for the exact product.
Does a food category always contain partially hydrogenated oil?
No. Formulations differ between brands, markets, and time periods. Check the label for the product you are considering.