Fats are usually classified as saturated or unsaturated. The primary chemical difference between the two is that the carbon atoms of saturated fats have all of the hydrogen they can hold, which is why they are referred to as saturated; the carbon atoms of unsaturated fats have at least one location where hydrogen can be added. Monounsaturated fats, also known as monounsaturated fatty acids, or MUFAs, have at least one double-bonded carbon in the molecule, which has room for more hydrogen.
Saturated fats come primarily from animal and dairy products, such as meat, eggs, whole milk, and butter. These are generally solid at room temperature, and are much more difficult for the body to process in large quantities. In contrast, unsaturated fats are liquid at room temperature and come primarily from plants and seafood, and are much more easily processed.
Monounsaturated fats have significant health benefits, including the ability to reduce low-density cholesterol (LDL) which can build up as plaque in the vessels and arteries, increasing the chance of heart disease or stroke. Monounsaturated fats also increase high-density lipoprotein (HDL), known as good cholesterol. HDL is thought to decrease plaque in the arteries, and to take cholesterol found in the blood away from the arteries and into the liver, where it can be passed out of the body. In this way, HDL actually provides protection against heart disease and stroke.
Monounsaturated fats are also able to reduce triglycerides, a form of fat found in the blood. Elevated levels of triglycerides are associated with diabetes and heart disease and can be caused by obesity, lack of physical activity, smoking, excess sugar intake, alcohol and a high carbohydrate diet. High triglyceride levels appear to pose an even greater danger of heart attack in women than in men.
At one time, doctors recommended low-fat diets as a way to prevent heart disease and stroke. While it is true that low fat diets do reduce LDL and total cholesterol levels, they also tend to be high in carbohydrates and have the negative side affects of increased triglyceride levels and decreased HDL. Research has shown that diets high in monounsaturated fats are actually more effective than low-fat diets in preventing heart disease. Most health organizations recommend a diet in which approximately one-third of the daily calorie intake comes from unsaturated fats, while only a small percentage should come from saturated fat products.
Monounsaturated fats are found in many vegetables, nuts, seeds and fish. Cooking oils which are high in these fats include canola, peanut, sesame, sunflower, and olive oil. Pumpkin, sesame, sunflower, and squash seeds are excellent sources, as are almonds, walnuts, macadamias, pecans, pistachios, and hazel nuts. Fish which are high in monounsaturated fats include herring, halibut, mackerel and eel. Avocados, peanuts, tofu, kidney beans, falafel and hummus are additional sources of monounsaturated fats.
While it is important to replace saturated fats with unsaturated fats in the diet, moderation should be exercised. Foods containing MUFAs tend to be higher in calories than other foods, and the fact that they are healthy does not prevent a person from becoming obese by overindulging. Exercise and a properly balanced diet should be part of a total health plan.