Good fat and bad fat and trans fat, OH MY! The great fat debate is on. Here's some fat facts to help you sort out all the info swarming around you.

Fats 101

All fats and oils contain a mixture of three different types of fatty acids – saturated, mono-unsaturated (MUFA) and polyunsaturated (PUFA).

Saturated Fat

Saturated fatty acids are fully "hydrogenated," meaning that the chain of carbons that acts as the fatty acid's core has a hydrogen atom attached at every possible connection point. These fatty acids can then snuggle up to each other getting very compact - so snug that they exist in solid form at room temperature. Saturated fat is considered "bad" because it raises total cholesterol and low-density lipoprotein (LDL) levels, which can increase your risk of cardiovascular disease and type 2 diabetes. Meats, eggs and butter are the main saturated fatty acid sources, but there are some naturally saturated vegetable oils (coconut and palm oil).

Unsaturated Fat

Unsaturated fatty acids are either mono- or polyunsaturated based on how many double bonds (kinks in the carbon chain) there are. The kinks prevent these fatty acids from packing it in too tightly, so they exist in a liquid form. Unsaturated fats are referred to as "good" fats because they raise levels of high-density lipoprotein (HDL), which is the good type of cholesterol. They also lower LDL cholesterol and fight inflammation. The higher your HDL and lower your LDL levels, the better protection you have against developing heart disease and other chronic diseases.

You can find MUFAs in vegetable, nut or seed oils as well as meat and dairy products. PUFAs are most commonly found in oils but are also found in fish, nuts and avocados. The most popular PUFAs are omega-3 and omega-6. Omega-3 fatty acids are linked to heart health and may also combat depression, reduce inflammation and improve immunity.

Trans Fat

Trans fats are born when extra hydrogen atoms are added to vegetable oils during processing to make liquid oils more solid. Voila! They become partially-hydrogenated. Trans fats lower your HDL (good cholesterol), and increase your risk for diabetes, cardiovascular disease and metabolic syndrome. Trans fats lurk in processed foods, fried foods, baked goods, and margarines made with partially-hydrogenated oils. Stay away.

What do the professionals say?

The mantras of 'low-fat' and 'fat-free' have driven people away from fat and right into the open arms of refined carbs – not a healthy trade. The latest research is not saying that saturated fat is good for you, but rather that saturated fat is not the only problem.  AND updated their Position Statement on dietary fat consumption in 2014 to say that for the healthy adult population, fat should make up 20 to 35 percent of total calories consumed (less than 10 percent should be from saturated fat).

So instead of vilifying fat as a whole, aim to replace saturated fat with PUFAs (mostly) and MUFAs. Remember, the big picture of your overall dietary pattern is more important than specific amounts of individual nutrients. Shoot for a diet filled with a variety of whole, unprocessed foods from all the different food groups and enjoy extras in moderation.

A "Healthy" Trap

Coconut oil is getting a lot of recent press for many different health benefits. It is high in medium-chain triglycerides (MCTs) lauric acid and myristic acid, which can be broken down quickly rather than stored away in the body's fat bank. Other MCTs (caprylic acid and capric acid) have been successful in decreasing body fat and improving weight loss when compared to olive oil. Unfortunately, coconut oil does not contain those specific MCTs.  There is currently insufficient evidence that coconut oil aids in weight loss, lowers cholesterol, reduces chronic fatigue or treats diabetes, Crohn's disease, irritable bowel syndrome or thyroid conditions. Since the fatty acids in coconut oil have been shown to increase cholesterol levels, the consumption of coconut products is not currently recommended by the Academy of Nutrition and Dietetics (AND).

Kerri Link Heckert, a registered dietitian at the Children's Hospital of Philadelphia, has been in the fitness and nutrition industry for the past 7 years. She is a yoga instructor (RYT-200), ACSM certified Health Fitness Specialist and certified personal trainer. She earned her Masters at Drexel University and currently lives in the Philadelphia suburbs.


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