Good Fat, Bad Fat

Sort out which fats help and which harm – and where to get more of the good stuff

WWe’ve come a long way, baby ... in what we understand about fat and its role in our overall and cardiovascular health.

However conflicting research findings over the last 30 years might leave us confused as to the current recommendations about how much – and what kinds – of fat to include in our diets. It’s difficult to separate the “good fats” from the “bad fats.”

Fats: Angels or Devils?

Even though we don’t think of our foods as combinations of chemicals, the tasty morsels we consume are essentially combinations of carbohydrates, proteins, fats and other components. The chemical structure of each food component determines what our bodies do with it. Proteins are critical to body structures such as hormones, bones and muscles, while carbohydrates serve primarily as an energy source. Fats are used for energy, but also can act as chemical messengers in some of our metabolic and inflammatory pathways.

Fats are categorized by their various chemical structures: saturated (SFA), monounsaturated (MUFA) and polyunsaturated (PUFA). These categories simply reflect the number of double bonds in the carbon chain and determine how the fat acts in our body.

The chemical structures gives each fat its typical flavor, aroma and food stability characteristics. For example, saturated fats are very stable even at room temperature (butter and lard) while the unsaturated fats (safflower and olive oils) can spoil more easily if not refrigerated.

Most trans fats are manmade during processing of polyunsaturated fats when they are processed into shelf-stable convenience foods.

The chemistry of these fats tempts us to label them as “healthy” or “unhealthy.” In reality, most foods we consume are a combination of the different types of fats, and the research around the health risks and benefits of each type is confusing at best.

In general, we have associated animal products with saturated fats and plant products with unsaturated fats. Both saturated fats and trans fats continue to be considered “unhealthy” fats as they have been shown to increase LDL (bad cholesterol) and be more strongly associated with the risk of cardiovascular disease and some types of cancer.

Past and Present

Common advice in the 1960s and ’70s was to decrease saturated fat intake and limit overall fat in the diet to 30 percent of the calories in favor of a higher carbohydrate diet. This advice was apparently based on limited epidemiological studies concerning the role of various fats in the diet.

Americans achieved these recommended changes in fat intake, yet obesity and lipid issues are still prevalent.

Given the rise in obesity despite achieving a lower-fat diet, recently the role of carbohydrates – especially as sugars – in the diet has come under fire.

While many studies still support a reasonable limit on the consumption of saturated fats, the overall role of fat in the diet remains somewhat controversial.

With the research showing that some fats are beneficial to our health, low-fat diets have fallen out of fashion in favor of a message of moderation and balance.

The current Dietary Guidelines for Americans from the National Academy of Science and Institute of Medicine still recommend choosing fewer foods with saturated and trans fats and consuming more monounsaturated fats and polyunsaturated fats, as well as more plantbased foods. They also recommend limiting fats to 20-35 percent of your total caloric intake.

Fats in Your Food

With these recommendations, consumers are eager to learn how “healthful fats” can help them avoid disease.

Polyunsaturated fats seem to have consistently weathered the research as fats that have a positive association with health. They have been shown to improve HDL (good cholesterol) and decrease LDL, both desirable influences.

Omega-3 fatty acids are part of the polyunsaturated class and are strongly touted for their anti-inflammatory and health-promoting effects. Omega-6 fatty acids are also essential, but are sometimes associated with more inflammation and some negative health effects.

The optimal balance between Omega-3 and Omega-6 chemistries is a current topic of scientific debate.

The USDA recommends eating a 4-ounce portion of seafood – fatty fish such as salmon, herring or mackerel –twice a week, as these contain high levels of Omega-3s.

To improve the polyunsaturated and monounsaturated fats in your diet, replace high-fat animal products and highly-processed foods with nuts, seeds and oils. Simple ideas include:

• Adding walnuts to your morning oatmeal or your trail mix snack.

• Including some olives and sunflower seeds on your salads.

• Mixing avocado as part of your salsa.

• Grinding chia or flax seed into a morning smoothie in place of anything sugary.

• Eating 4 ounces of fatty fish at least two times per week.

• Using only lean meats and low fat dairy products.

• Avoiding highly processed foods.