1 Saturated fat may also increase your risk of type 2 diabetes. 2  Trans fat. 3  This is a type of fat that occurs naturally in some foods in small amounts. 4  But most trans fats are made from oils through a food processing method called partial hydrogenation.
http://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/in-depth/fat/art-20045550
Your body makes its own fat from taking in excess calories. Some fats are found in foods from plants and animals and are known as dietary fat. Dietary fat is a macronutrient that provides energy for your body. Fat is essential to your health because it supports a number of your body's functions. Some vitamins, for instance, must have fat to dissolve and nourish your body. But there is a dark side to fat.
http://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/in-depth/fat/art-20045550
Protect Your Arteries. Replacing trans and saturated fats with omega-3, omega-6, and omega-9 has been shown to prevent atherosclerosis or “hardening of the arteries.” Think of saturated or trans fats as solids that can eventually clog your arteries, which keeps the blood from flowing properly.
http://www.goodfats101.com/health-benefits/heart/
Omega-9 fatty acids have been shown to increase HDL (“good”) cholesterol and decrease LDL (“bad”) cholesterol, thus helping to eliminate plaque buildup in the arteries, which may cause heart attack or stroke.
http://www.goodfats101.com/health-benefits/heart/
Reduce Cholesterol. The Dietary Guidelines indicate most Americans consume too much saturated and trans fats and not enough unsaturated fats (monounsaturated and polyunsaturated fats). In fact, the most recent guidelines recommend replacing bad trans and saturated fats with good fats. A diet high in unsaturated fat helps reduce heart disease and stroke by reducing both total and low-density lipoprotein (LDL) cholesterol and triglyceride (fat in the blood) levels.
http://www.goodfats101.com/health-benefits/heart/
Take fat for example. For years it has been painted as an evil monster and the root cause of high cholesterol, heart disease and obesity. But scientific studies now show that there are many benefits of eating more fat, and it’s time we started rethinking this essential part of our dietary regime. In short, fat has gotten a bad rap.
http://www.lifehack.org/articles/lifestyle/the-5-surprising-benefits-eating-more-fat.html
Good Fats for the Heart. According to the American Heart Association, an estimated 80 million Americans are affected by some type of cardiovascular disease. However, there are positive steps those affected by heart disease can take in order to improve their health condition.
http://www.goodfats101.com/health-benefits/heart/
Essential vitamins such as A, D, E and K are not water soluble and require fat to get transported and absorbed by the body. These vitamins are crucial for brain health and many of our vital organs.
http://www.lifehack.org/articles/lifestyle/the-5-surprising-benefits-eating-more-fat.html
Other studies tell us that the obesity epidemic, which has doubled in the last 50 years, is not because of us eating too much fat but because of our consumption of readily available carbs and sugar, including glucose found in fruits and juices.
http://www.lifehack.org/articles/lifestyle/the-5-surprising-benefits-eating-more-fat.html
Trans Fat. Not all fats are created equal. There are “good” fats found in foods like salmon, olive oil, and nuts, and “bad” fats found in foods like butter. But the worst fats, and the hardest to avoid, are trans fats.
http://www.publichealthlawcenter.org/topics/healthy-eating/trans-fat
what is the benefit of trans fats
The benefit of trans fats is eventually clog your arteries, which keeps the blood from flowing properly.  Trans fats can eventually clog your arteries, which keeps the blood from flowing properly.