Scientists Say: Unsaturated fat

When carbons form double bonds in a fat molecule, things get kinky

Olive oil flows because it’s an unsaturated fat.

Magone/istockphoto

Unsaturated fat (noun, “Un-SAT-yur-a-ted FAT”)

This is a type of fatty acid. Fatty acids are carbon chains with hydrogens on the outside. When a fatty acid is saturated, each carbon is bound to two carbons — each by a single bond — with two hydrogens taking up the remaining bonds on either side. But sometimes, the carbons bond to each other with double bonds, leaving room for only one hydrogen. This makes the fatty acid unsaturated — meaning that it doesn’t have as many hydrogens as it could.

These double bonds do more than take hydrogen’s spot. They also cause the carbon chain to bend. The kinky chains don’t line up well with each other. This makes unsaturated fats liquids at room temperature. These fats are usually oils, such as olive oil or corn oil.  

In a sentence

Scientists and doctors used to think that unsaturated fats — including trans fats — were better for you than saturated fats.

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Bethany is the staff writer at Science News for Students. She has a Ph.D. in physiology and pharmacology from Wake Forest University School of Medicine.

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