Not all fat is bad for you. In fact, some fats are crucial for good health. While it's important to limit your fat intake to 20 to 35 percent of your calories, it's also important to ensure that within this range you're mostly eating a variety and balance of "good" fats and not "bad" fats. Saturated fat and trans fat are the two "bad" fats. Together they should make up no more than 10 percent of your total calories and are best avoided altogether.
Too much saturated fat increases your cholesterol levels, raises the risk of blood clots, atherosclerosis (artery blockage), and coronary heart disease. Saturated fats are found mainly in animal products such as whole milk, cheese, butter, cream, fatty meats, sausages, and also in processed foods. Coconut, palm and other tropical oils are the only plant foods that contain significant amounts of saturated fat. Saturated fats are usually solid or waxy at room temperature.
This fat also raises blood cholesterol levels and increases the risk of heart disease. Trans fat is formed when hydrogen is added to liquid vegetable oils making them more solid – a process called hydrogenation. Trans fat is found mostly in commercial baked goods and fried foods, and in shortenings and margarines that are labeled “hydrogenated” or “partially hydrogenated”.