How are trans fats different from unsaturated fats with a cis configuration?

The primary difference between trans fats and unsaturated fats with a cis configuration lies in their molecular structure and physical shape, which significantly impacts how they behave in food products and the human body.

Molecular Configuration

• Cis Configuration: In naturally occurring unsaturated fatty acids, the hydrocarbon chains adjacent to the carbon-carbon double bond lie on the same side of the molecule. This creates a "v" shape or a bend at the double bond, which prevents the molecules from packing tightly together, typically resulting in a liquid state at room temperature.12
• Trans Configuration: Through the industrial process of hydrogenation, the molecule is forced into a twist that places the hydrocarbon chains on opposite sides of the double bond. This results in a linear, straight-chain structure that closely resembles the shape of a saturated fat.2

Impact on Food and Health

Because of this linear structure, trans fats are more stable and can be transformed into a soft-solid or solid consistency, which helps extend the shelf life of processed foods like margarine, baked goods, and deep-fried items.32

Unlike cis fats, which are essential components of biological systems, the consumption of trans fats is linked to negative health outcomes. They increase "bad" LDL cholesterol while simultaneously decreasing "good" HDL cholesterol, thereby raising the risk of cardiovascular disease and other health issues.324