Unfortunately, fat has had a bad wrap over the years but things are beginning to change. What we need to keep in mind is that fat is an essential nutrient, a great energy source, provides insulation for our nerves and helps us absorb fat-soluble vitamins like vitamins E and A. In addition, certain types of fat, such as omega-3s and monounsaturated fats are really healthy. In other words, not all fats are created equal.
To understand fat, first you need to understand the language. The building blocks of fat are called fatty acids. There are three main types of fatty acids found in foods: monounsaturated, polyunsaturated, saturated fatty acids. Although these names seem complicated, they simply refer to the basic structure of the fat. These different fatty acids are combined into triglycerides, which is how fat is found in the fats and oils we eat. Take olive oil for example; even though it’s famous for being high in monounsaturated fat, it still contains a small percentage of polyunsaturated fat and saturated fat. The same is true for other fat sources as well.
Enough with the chemistry, the important thing to remember about different types of fat are how they affect your body and what are the food sources.
Polyunsaturated fat is usually liquid at room temperature and comes mainly from plant foods, especially their oils. For example, soybean, corn, sunflower, peanut and sesame oils are all rich in polyunsaturated fat. Omega-3s are a special kind of polyunsaturated fat associated with numerous nutrition benefits.
Omega-3s are considered essential fatty acids because we must get them from our diet and they are found in both plant and animal foods. Plant sources provide only one type of omega-3, called alpha-linolenic acid, and rich sources include flax oil and seeds, walnuts, hemp seeds and oil and soybean oil.
Marine sources provide two different types of omega-3s, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Rich sources of EPA and DHA are fish like salmon, tuna, herring, mackerel and sardines.
Monounsaturated fats are usually liquid at room temperature and tend to have a neutral effect on cholesterol levels, which is a great for keeping your heart healthy. Avocados, canola oil and olive oil are good sources of monounsaturated fat.
Saturated fats tend to be solid at room temperature and when eaten in excess can raise cholesterol levels. Animal fat (except most fish), butter, tropical oils such as coconut and palm oil and many packaged snack products are sources of saturated fat.
Although a very small amount of trans fat occurs naturally in animal products, the overwhelming majority of it is formed when vegetable oils are chemically altered in the process of partial hydrogenation. Because trans fat has a different structure, it also behaves differently in the body than other types of fat.
A high intake of trans fat from processed foods seems to increase both total and LDL cholesterol levels (the lousy kind) while lowering HDL cholesterol levels (the happy kind) – the exact opposite of your goals for maintaining a healthy heart
Foods that have partially hydrogenated vegetable oils in the ingredient list typically have the most trans fat. The primary sources of trans fats in Australia and New Zealand are processed foods like crisps, doughnuts, pies, pastries, and biscuits.
Quantity vs. Quality
When you see that there are different types of fat, it becomes clear that the quality of fats you choose is equally, if not more important as the quantity you eat. Just keep in mind that fats do provide 37 kilojoules per gram so be careful not to overdo it so you can manage your weight.