Which type of fat is characterized by having at least one double bond in its fatty acid molecules?

Unsaturated fats are characterized by having at least one double bond in their fatty acid chains. This structural feature affects their properties, making them typically liquid at room temperature, as seen in oils like olive oil and canola oil. The presence of double bonds introduces kinks in the fatty acid chains, preventing them from packing tightly together, which is why they remain liquid.

In contrast, saturated fats do not have any double bonds in their fatty acids and are usually solid at room temperature, found in products such as butter and lard. Trans fats, while having a similar structure to unsaturated fats due to the presence of double bonds, have a specific configuration that makes them behave more like saturated fats, contributing to health risks. Hydrogenated fats are created through a process that adds hydrogen to unsaturated fats to make them more solid and shelf-stable, which results in a loss of their original double bonds. Therefore, the defining characteristic of unsaturated fats is the presence of one or more double bonds in their fatty acid molecules, setting them apart from the other types of fats listed.