Q. I'm always hearing about "healthy" and "unhealthy" fats; what do these terms really mean?
A. Generally, when people speak of “healthy” fats, they’re referring to the monounsaturated and polyunsaturated kinds that help protect the heart by lowering “bad” LDL cholesterol, raising “good” HDL cholesterol, reducing inflammation of blood vessels—or a combination of all three of these effects. Monounsaturated fats (naturally found in nuts, avocados and olives) and polyunsaturated fats (omega-3s in fish and flax and the omega-6s in vegetable oils) fall into this “healthy” group.
Saturated fats and trans fats are often referred to as “bad” or “unhealthy” fats because they contribute to increased heart risk by increasing LDL cholesterol. Saturated fats are found naturally in foods of animal origin (think: butter, meats, whole-fat dairy) and are solid at room temperature. Tropical oils, including coconut and palm oil, also are rich in saturated fats. Trans fats, on the other hand, are manmade: produced when food processors “partially hydrogenate” (i.e., add extra hydrogen molecules) to unsaturated plant oils to make them more stable. This increases the shelf life of foods, which translates into a greater bottom line for manufacturers. Because trans fats have been shown to harm the heart, and nutrition experts advise avoiding foods that contain them, food companies have been required to list the trans-fat content on the nutrition labels since January 2006. But it’s important to note that if a product contains less than 0.5 gram of trans fat, the listed amount can be rounded down to 0. It’s best to avoid all processed foods that list “partially hydrogenated” on the ingredients label.
Bottom line: Not all fats are “bad.” In fact, studies show that replacing “bad” fats (saturated and trans) with “healthy” unsaturated ones from foods including fish, nuts and olives is a more effective way to help your heart than dramatically limiting overall fat intake.