Of the three macronutrients (carbohydrates, fats and proteins) fats are generally cast as the villain of the group – often attributed with weight gain and an endless list of health problems. We know protein builds, maintains and repairs our cells and that carbs give us energy. However, most people remain in the dark about the many vital functions fat plays in our bodies. Instead it is often viewed as the macronutrient to avoid at all costs - with low fat diets and foods popping up everywhere in recent years. A common misconception is that fat makes you fat! While it can contribute to weight gain, obesity is much more complicated than just eating too much of a single nutrient. It is true that a fat has 9 calories per gram (almost double the 4 calories per gram in protein and carbohydrates); however eating excess calories, from any source, can cause weight gain.'Good' Fats No, this is not an oxymoron– some fats are actually beneficial to our health. Unsaturated fats aka the "good" fats are broken down into two categories - monounsaturated and polyunsaturated fatty acids. But before we can jump into what these two fats do and where to find them, a quick recap on cholesterol is needed. The first LDL cholesterol is what typically comes to mind when we think of cholesterol. It’s the "bad" stuff that causes blockages in our artery walls and restricts the blood flow – leading to cardiovascular diseases and high blood pressure. HDL or "good" cholesterol on the other hand helps remove the LDL cholesterol from your body, thereby reducing health risks. The goal is to raise our HDL, while lowering our LDL – with an optimal ratio of LDL to HDL of 2 or 3 (definitely less than 4). Now back to fats. Generally believed to be the healthiest of the fats, monounsaturated fats reduce our LDL cholesterol while boosting our HDL cholesterol. Liquid at room temperature but solid if refrigerated, this heart-healthy fat is an excellent source of vitamin E, a powerful antioxidant that is typically lacking in most people's diets. It has also been shown to reduce the risk of cancer and inflammation as well as to help stabilize blood sugar levels. Major sources include olives, avocados and nuts such as almonds, hazelnuts and pecans as well as plant oils such as peanut, canola and olive oil. The other "good" fat, polyunsaturated fatty acids, also helps to lower our cholesterol and triglyceride levels, especially when they replace their not so healthy sibling - saturated fats. One polyunsaturated fat that has received a lot of hype lately is none other than Omega-3. Considered an essential fatty acid, our bodies need Omega-3 for many vital functions, including controlling blood clotting and building cell membranes in the brain. As we cannot produce this "essential" nutrient, we need to get it from food. Cold water-fish, such as salmon, trout, catfish, mackerel, contain the most effective form of the fat. However, for those of who are not fish lovers, other forms of the fat can also be found in certain nuts, dark leafy vegetables, soybeans, oils (flaxseed and some vegetable ones) and chia seeds, the vegetable source with the highest amount omega-3. 'Bad' FatsUnfortunately nothing in life is perfect, especially fats – so on to those so called "bad" fats. They are broken down into two categories: Saturated Fat – the traditional villainThis artery-clogging fat is primarily found in animal products such as meats, poultry fat, dairy products made from whole or 2% milk as well as butter and cream. This "evil" nutrient can also be found in certain plant products such as coconut and palm oils as well as cocoa butter (sigh…yes chocolate). Unlike unsaturated fat, saturated fat raises our LDL, "bad," cholesterol levels and clog our arteries, thus increasing our risk for heart diseases. What's more, we do not even need to consume it as our bodies can naturally produce all the saturated fats that we require! While 20-35 percent of our daily calories should come from fat, it is recommended that less than 7% come from saturated fats. Trans Fats - when good fats go badUnlike the other two groups, Trans fats are found only in tiny quantities in foods, such as in animal products, the majority of them are actually man made. Here is a short description of what happens: Food manufacturers, in an effort to give their products a longer shelf life, heat innocent unsaturated fats in the presence of hydrogen gas (a process known as "hydrogenation"). Partially hydrogenating vegetable oils are more stable, therefore less likely to spoil, can be transported more easily, and can withstand repeated heating. While this may be great for the food manufacture, it is unfortunately really really bad for consumers.So why exactly are these fats so terrible? To begin with, like saturated fats, trans fats raise our LDL cholesterol. However it gets worse. At the same time, they also lower HDL cholesterol, the kind that helps unclog arteries. As a result, they increase the risk of coronary diseases. They are so bad, that a few years ago New York City banned the usage of all but minute quantities of trans fats in its restaurants. This move was followed quickly by the entire state of California, Philadelphia and Boston banning the use of the fat in their restaurants. If it didn’t already sound awful enough –it gets worse, especially for those with a sweet tooth. Trans fatty acids are used extensively in the most tasty and tempting of foods. Major sources include vegetable shortenings and certain margarines as well as baked goods (i.e. cakes , cookies, muffins, crackers, pie crusts and pizza dough), snack foods (i.e. popcorn, chips and candies) and of course fried foods (i.e. doughnuts and French fries). However, it is tricky to know which foods contain this deadly ingredient, as if the product contains less than 0.5 grams, it will be labeled as trans fat free. So take a look at the ingredients, if a product contains "hydrogenated oils", "partially hydrogenated vegetable oils" and "shortening", put it down and walk away. The moral of the story: choose your fats wisely…So now that we covered that common misconception, let's move on to the next - that a fat is a fat. Again not exactly true. Not all fats are created equal. Some are good, some are bad and some are just plain wrong. So here is a rundown on the different types of fats and where to find them.