Fat
Dietary fat is one of the nutrients that fuels the body. Unlike carbs and protein which give the body 4 calories per gram, fat is more than twice as energy dense, providing the body with 9 calories per gram. Though fat is associated with greasy foods such as hamburgers and pizzas, it is a necessary nutrient that has important functions within the body.
Fats Explained
Fat is a nutrient that provides the body with 9 calories per gram. Aside from providing energy, it also has some other key functions which include aiding in the absorption of fat soluble vitamins and producing hormones. One of the biggest misconceptions surrounding this nutrient is that eating fat will make you fat. Fat does not make you fat, excess calories is responsible for that.
Saturated vs. Unsaturated Fats
There are two main types of fat, saturated and unsaturated fats. Saturated fats are usually referred to as the bad or unhealthy fats while unsaturated fats are referred to as the good or healthy ones. The difference between the two fats is their chemical makeup resulting in a different behavior inside the body.
Saturated fats are found in animal products and are unhealthy because they generally raise the level of bad cholesterol (LDL) in the body. Sources include dairy products (milk, cheese, butter, ice cream), meats and eggs.
fishUnsaturated fats are found mostly in vegetable products and are healthy because they tend to lower the bad cholesterols (LDL) while raising levels of good cholesterols (HDL). Sources include vegetable oils (olive & canola oil), nuts, seeds and seafood (salmon, tuna, shrimp).
Trans Fat
Trans fat is a 'special' kind of fat. Its main purpose is to help improve flavor and extend shelf life. These benefits come at a cost. Trans fat tends to increase levels of bad cholesterols (LDL) while decreasing levels of good cholesterols (HDL). Sources of trans fat include pastries, peanut butter (the non-natural kind), vegetable shortening, margarine and any food that contains fully or partially hydrogenated vegetable oil. Check the nutrition label for more information.
How much fat should I eat each day?
Over the years, fat has become a dirty word. Its meaning has become synonymous with weight gain because the 'fat' we eat in foods is the same word we use to describe someone that is overweight. Though eating fat can lead to excessive weight gain, it's not the fat that's to blame, it's excess calories that you should point the finger at.
Whenever you eat more calories than you burn, your body will store that extra energy as fat for later use. Whether or not you eat too much fat, protein or carbohydrates, the result will be the same; fat storage. Eating fat does not make you fat.
The End
Fat is an essential nutrient that you cannot live without. Losing weight by eliminating fat (or any other macronutrient) from your diet is unhealthy which will lead to less than desirable results. A balanced diet that contains good fats while limiting the bad ones will lead to a healthier and more productive lifestyle.
Source: http://straighthealth.com/pages/qna/what-is-fat.html