Fats are one of the most misunderstood nutrients, and understandably so. Fats used to be synonymous with two groups of foods: commercially baked goods — which includes pastries, pies, and cookies — and fast food staples, like hamburgers and french fries. What became apparent over time was that these fats, while tasty, are also deadly. Research showed that excessive consumption led to an increased incidence of obesity, diabetes, hypertension, heart disease and cancer. So these foods were placed on the highest of pedestals, all the way up on the tip top of the food pyramid, with advisement from health officials to only to be enjoyed on occasion.
But things have changed. Now, certain “fats” can be regarded as health foods, and are actually the mainstays of some of the most popular diet crazes out there, including the Paleo and Mediterranean diets. To understand how some fats can be beneficial while others are deleterious, you must delve deeper into the realm of biochemistry. What you see is dietary lipids are actually made up of complex conformations of fatty acids, and it is the arrangement and the amount of double bonds in these fatty acids that largely differentiates a “good” fat from a “bad” fat.
“Bad” fats are made up of trans or saturated fatty acids, particularly solid fats. Foods high in trans fatty acids (such as the commercially produced baked goods) are inexpensive to produce and have long shelf lives. Also, anytime you see the term “partially hydrogenated oil” in the ingredient listing, you know that trans fats are included. Saturated fats largely come from animal sources, which includes fatty meats and dairy products.
“Good” fats are polyunsaturated fats (meaning that chemically, they have more than one double bond.) These can be further broken down into omega-3 and omega-6 fatty acids. Omega-3 fatty acids are plant and seafood-derived while omega-6 fatty acids are commonly found in poultry, vegetable oils, nuts and seeds.
One reason foods high in trans and saturated fatty acids are bad and foods rich in omega-3 and omega-6 fatty acids are good has to do with the effects these fatty acids have on our cholesterol levels. Diets high in trans and saturated fats will lead to elevated LDL cholesterol, which will promote increased plaque and clot formation in one’s blood vessels leading to increased risk of heart disease and strokes. On the other hand, diets high in polyunsaturated fatty acids can also have positive anti-inflammatory effects and can lead to an elevation in one’s HDL cholesterol, which is cardioprotective and decreases one’s risk of heart disease and stroke.
I encourage you to be aware of your own dietary fat consumption. My recommendation for fat intake is simple: Consume less than 10 percent of calories from saturated fats. Replace solid fats with oils when possible. Limit foods that contain synthetic sources of trans fatty acids (such as hydrogenated oils) and keep total trans fatty acid consumption as low as possible. And finally, eat fish because it is rich in omega-3 fats. If you’re interested in assessing your cholesterol level, ask your doctor to run a lipid panel and determine if your LDL cholesterol and HDL cholesterol are within the recommended ranges. And remember, it’s important to consider not just the quantity of fat in your diet but also the quality of fat.
Mark Gottschlich is a medical student at the Ohio University Heritage College of Medicine. Contact him at firstname.lastname@example.org.