The logic makes sense, eating fat will cause fat gain. You may even have heard of good fats and bad fats. Maybe eating good fats will prevent you from putting on some extra pounds while bad fats are a quicker way to ensuring a larger pant size and a trip in the ambulance. There is more to the story of fat and its mysteries.
Fat is one of the three macronutrients, including proteins and carbohydrates, consumed that our bodies use for energy and other important processes. Whereas protein and carbohydrates contain 4 calories per gram, fat is more calorie dense containing 9 calories per gram.
Fat is essential for:
Vitamin A, D, E, and K are fat soluble meaning they all need fat to be properly absorbed and utilized. The process to digest fats is longer than carbohydrates and proteins and thus helps you stay satiated for longer periods of time.
Fat is a part of every cell membrane and helps transport nutrients and metabolites across cell membranes.
Your hormones are made from fat, more specifically cholesterol. Eating an adequate amount of fat in your diet is important for regular hormone function.
Fat is one of the main energy sources of your body besides glucose. If you run out of glucose or muscle/liver glycogen, you have thousands of calories stored in fat to fuel your body.
Nervous System Your brain is made up of mostly fat and water. Getting adequate amounts of fat is essential for brain function.
Types of fats: Trans fats NOT GOOD. DO NOT EAT. Trans fats are processed fats made to increase the shelf life and texture of products. They are proven to increase the risk of heart disease, raise bad cholesterol, and make it difficult to lose body fat (2). Look out for food labels that list trans fats or hydrogenated oils in the nutrition facts.
Saturated fats get a bad reputation but are actually play important roles in the body. Saturated fats are fats which are solid at room temperature and are prominent in animal products such as dairy, meat, and eggs. They are termed saturated because they have more hydrogen ions in a fat molecule than an unsaturated fat molecule. Increasing saturated fat intake has been shown to increase total cholesterol, both the "good" HDL and the "bad" LDL (1). It is currently unclear how saturated fat negatively impacts health as there aren't any good links to saturated fat intake and cardiovascular disease. However, when paired with processed carbohydrates, it is shown to increase LDL cholesterol, increase systemic inflammation, and increase risk for heart disease.(1)
There are two types of unsaturated fats:
Mostly plant based fats coming from sources such as nuts, seeds, avocados, and olives. Considered the more healthy fat as consumption of these fats has been shown to reduce cholesterol and risk for heart disease.
Polyunsaturated fats Found in plant and animals foods such as some nuts, seeds, and fish. Some examples of essential polyunsaturated fats are Omega 3 and omega 6 fatty acids.
OMEGA 3 TO OMEGA 6 RATIO Essential fatty acids are fatty acids your body cannot produce on its own and has to be obtained from an external source. The typical American diet contains an abundance of omega 6 fatty acids and a lack of omega 3 fatty acids. An unbalance ratio of omega 6 to omega 3 fatty acids is associated with increased inflammation and risk for heart disease (3). - The average American diet has from about a 12:1 to 25:1 omega 6 to omega 3 ratio (3) The healthy range should be from 1:1 to 4:1 omega 6 to omega 3 (3).
KEY TAKE AWAYS 1. Fat does not make you fat, too many CALORIES makes you fat. 2. Trans fats and hydrogenated oils are processed fats you should steer clear of. 3. It is unclear how excess saturated fats negatively affect your health in absence of refined and processed carbohydrates. 4. It is important to get a mix of fats in your diet, saturated and unsaturated. 5. Increase your omega 3 intake to balance your omega 6:omega 3 ratio.
(1)J Bruce German, Cora J Dillard; Saturated fats: what dietary intake?, The American Journal of Clinical Nutrition, Volume 80, Issue 3, 1 September 2004, Pages 550–559
(2) Ascherio, A., Katan, M. B., Zock, P. L., Stampfer, M. J., & Willett, W. C. (1999). Trans fatty acids and coronary heart disease. New England Journal of Medicine, 340, 1994-1998.
(3) Simopoulos, A. P. (2002). The importance of the ratio of omega-6/omega-3 essential fatty acids. Biomedicine & pharmacotherapy, 56(8), 365-379.