Scientists Say: Saturated fat

This type of fat is solid at room temperature

Butter is solid at room temperature because it’s got a lot of saturated fat molecules that line up nicely with each other.


Saturated fat (noun, “SAT-yur-a-ted fat”)

A saturated fat is a type of fatty acid. The core of a fatty acid is a long chain of carbon atoms linked together. In a saturated fat, each carbon is linked to two other carbons and has two hydrogens bound as well, with three hydrogens on the last carbon at the end of the chain. Each carbon only has a single bond between itself and the carbon atom on either side. All the other bonds are taken up by hydrogens. The molecule can’t fit any more hydrogens, so it is said to be saturated.

These long carbon and hydrogen chains are very straight. When they clump together, they line up easily. These straight lines make the fats solid at room temperature.

Saturated fats are most common in certain foods, such as red meats and dairy products. Oils such as coconut oil, though, also have a lot of saturated fat.

In a sentence

Scientists and doctors used to worry that saturated fats were unhealthy but found that replacing them with sugars or trans fats was bad, too.

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Bethany Brookshire was a longtime staff writer at Science News Explores and is the author of the book Pests: How Humans Create Animal Villains. She has a Ph.D. in physiology and pharmacology and likes to write about neuroscience, biology, climate and more. She thinks Porgs are an invasive species.

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