by Audrey Miller
Fats get a bad rap. Firstly, because we associate the word “fat” with the atrocious fallacy that the word as an adjective could possibly and adequately describe a fellow human being’s appearance. And secondly, because fats were deemed “Public Enemy No. 1” back when the food pyramid was created in 1992. But we have come a long way since then.
Fats have been slowly but surely climbing back up the nutritional ladder to claim their rightful place in our health-conscious society. Our bodies need three macronutrients to survive: proteins, carbohydrates, and fats. To exclude one of these macronutrients would change the way our body functions. Obviously there are diets out there that intentionally leave out one macronutrient (for example: the ketogenic diet which excludes carbohydrates), but that’s really not how our bodies were designed to operate. We need fats to help absorb the nutrients we eat, to produce important hormones, and to keep our skin glowing and our hair shiny.
There are four types of fat: saturated, monounsaturated, polyunsaturated, and trans. The differences between these different types come from their structure at the molecular level. Fats are essentially long chains of hydrocarbons (Translation: carbon atoms and hydrogen atoms bonded together) capped with a carboxyl group made of carbon, oxygen, and hydrogen atoms. Saturated fats are made of only singly-bonded carbon atoms, while the other three include both singly-bonded and double-bonded carbons. These double bonds are considered to be “degrees of unsaturation.”
Depending on the number and type of double bonds, we get different types of fats. Monounsaturated fats have only one double-bonded carbon per chain, and polyunsaturated fats have multiple double-bonded carbons per chain. An easy way to remember this is to look at the words’ prefixes — mono meaning one (i.e. one degree of unsaturation in the hydrocarbon chain) and poly meaning many (i.e. many degrees of unsaturation). Trans fats are similar in the sense that they contain carbon-carbon double bonds, except these bonds are arranged in a “trans” configuration rather than the “cis” formation of the previously mentioned unsaturated fats. (And if you want a more complete explanation of these configurations, I would recommend registering for Dr. Oostendorp’s course on organic chemistry. But for now, just trust me that they are two completely different arrangements of the carbon and hydrogen atoms.)
So why should we care what fats look like at the molecular level? Well, these molecular differences cause visible differences in our foods. For example, the dense nature of saturated fats cause them to be solid at room temperature. Butter and coconut oil are excellent examples of saturated fats. The double bonds in mono- and polyunsaturated fats make bumps in the perfectly straight lines of molecules, causing them to be more fluid. Oils such as olive oil, canola oil and sesame oil include monounsaturated fats while soybean oil, sunflower oil, and corn oil include polyunsaturated fats. The “good fat” of salmon and other fish is also the polyunsaturated type of fat.
When it comes to healthiness, poly- and monounsaturated fats are essentially equal in the realm of health benefits. There is currently a debate on whether or not saturated fats are good or bad for you, but a recently published article in the European Journal of Nutrition showed that consuming whole-milk dairy products (i.e. products with saturated fats) has been linked to lower levels of obesity. So the debate is still out there, but the evidence is quite positive in the direction of re-accepting saturated fats into the “healthy” diet.
The one fat that is and always will be considered “bad” is trans fat. It is essentially an artificial fat, designed for products to have longer shelf lives because bacteria and fungi can’t even recognize it as a digestible fat. These imitation fats are indisputably correlated to heart disease, and we would all be smart to exclude it from our diets entirely. Avoid fried and uber-processed food, and you should be fine.
Bottom line: Fat is no longer the nutritional enemy it used to be. Rather, scientific evidence points to it being an important macronutrient for our overall health, just like proteins and carbohydrates. Just steer clear of those icky trans fats, and you’ll be on the road to macronutrient balance in no time.