The Skinny on Dietary Fats: What You Need to Know
For years, particularly in the 1980s and 1990s, many weight-loss diets promoted “low-fat” products. These recommendations often stemmed from the fact that fat contributes 9 calories/gram, and a notable fear that consuming fat would make someone gain weight. However, it is important to note that consuming fat in and of itself does not cause weight gain. Consuming excessive calories causes weight gain. In fact, fat is an essential part of the human diet.
Dietary fats play critically important roles, including but not limited to the following:
- Serve as the body’s main source of long-term energy and energy storage
- Provide structural support in the body and assist in injury prevention
- Support the absorption of many vitamins, such as vitamin A, vitamin D, vitamin E, and vitamin K are fat-soluble, which absorb best in the presence of fat
- Can optimize cholesterol levels if considered heart healthy (see below)
Please note that all fats are NOT created equal. Some dietary fats are considered heart-healthy, others are not.
Heart-Healthy Dietary Fats = Unsaturated Fatty Acids.
Unsaturated fats, either mono- or poly-unsaturated, are found in a variety of solid foods and oils. Examples include olives, olive oil, avocados, avocado oil, nuts and seeds, nut and seed butters, and fish. Foods containing these unsaturated fatty acids are noted for their ability to help improve blood cholesterol levels, which can decrease one’s risk of heart disease and may also help decrease the risk of type 2 diabetes. One particular type of polyunsaturated fat is made up of mainly omega-3 fatty acids and may be especially beneficial for heart health.
Unhealthy Dietary Fats = Saturated and Trans Fatty Acids
Saturated Fat. This type of fat comes mainly from animal sources of food, such as red meat, pork and full-fat dairy products. Saturated fats raise low-density lipoprotein (LDL or “bad”) cholesterol levels, which may increase one’s risk of cardiovascular disease. To reduce your intake of saturated fats, consider reducing red meat and pork intake to no more than 1-2x/week, and switch from full-fat to low-fat dairy products.
Trans Fat. This type of fat is mostly man-made from oils through a processing method called “partial hydrogenation.” In this process, oils change in form from a liquid to a more solid structure. When consumed, these “hydrogenated oils” and trans fats can increase total blood cholesterol, LDL (“bad”) cholesterol and triglyceride levels, as well as reduce high-density lipoprotein (HDL or “good”) cholesterol. This can increase your risk of cardiovascular disease. The best way to identify whether a food product contains trans fats is to read the ingredients list – “hydrogenated or partially hydrogenated oil” listed means that the product contains trans fats.
The Dietary Guidelines for Americans recommend that total fat sources make up 10-35% of one’s diet. If you are eating a 2,000-calorie a day diet, this means that 200-700 calories per day should come from fat sources. Most fat should come from heart-healthy, unsaturated fatty acids.
For more information on fats, schedule a consult with your dietitian.