saturated fat
Meaning of saturated fat: The kind of fat that stays solid on a cold plate, and the one most closely tied to raised cholesterol in the blood.
Definition of saturated fat
Saturated fat is a fat whose carbon chains carry no double bonds, so the molecules pack together tightly and the fat is usually solid at room temperature. Butter, lard, fatty meat, full-fat dairy, palm oil and coconut oil are the main sources. Diets high in saturated fat raise the level of LDL cholesterol in the blood, which in turn raises the risk of heart disease.
What does saturated actually mean?
A fatty acid is a chain of carbon atoms. Each carbon can hold hydrogen atoms, and a chain that holds all it possibly can is described as saturated with hydrogen. No gaps, no double bonds, no kinks. Straight chains stack neatly against one another, which is why butter is firm from the refrigerator while olive oil pours.
| Fat type | Structure | Typical sources |
|---|---|---|
| Saturated | No double bonds, straight chain | Butter, cheese, fatty meat, coconut oil |
| Monounsaturated | One double bond | Olive oil, canola oil, avocado |
| Polyunsaturated | Two or more double bonds | Oily fish, walnuts, sunflower oil |
| Trans | Double bond in a straightened form | Some processed and fried foods |
Why is it linked to heart disease?
Saturated fat in the diet reduces how efficiently the liver clears LDL particles, the ones that carry cholesterol out into the circulation. LDL levels in the blood therefore rise. Over years, cholesterol from those particles is deposited in artery walls, where it forms the fatty plaque of atherosclerosis. Narrowed and stiffened arteries supply less to the heart muscle and the brain, and a plaque that cracks open can trigger a clot. This chain of events is why saturated fat appears in almost every set of dietary guidance on heart health.
Is all saturated fat the same?
Not entirely. Saturated fatty acids differ in chain length, and their effects on blood cholesterol are not identical. Stearic acid, found in cocoa butter and beef fat, has a smaller effect on LDL than palmitic and myristic acids do. Food is also eaten as food rather than as isolated fat, and the rest of what is on the plate matters. Research increasingly compares whole foods rather than nutrients in isolation, which is why fermented dairy and processed meat can carry similar saturated fat content yet track differently in population studies. The broad guidance has held: replacing saturated fat with unsaturated fat lowers LDL, while replacing it with refined starch and sugar does not.
Also known as
Used in a sentence
Dietary counseling addressed the high saturated fat content of the reported intake.
Good to know
Saturated fat raises LDL cholesterol, but individual saturated fatty acids differ in how strongly they do so, and what replaces the fat in the diet changes the outcome.