Don't Be Foolish About Fats

Fats are one of the three macronutrients. Fats are made of carbon, hydrogen and oxygen and are built with a glycerol backbone with fatty acids attached. Fats are known by many names—fat, triglycerides, fatty acids, oils, esters, lipids. Some have different technical meanings, but all generally refer to dietary fats.

So let’s look at the details—yay chemistry! Like I said earlier, fats consist of a glycerol backbone and fatty acid tails. Triglycerides are named because there are 3 (tri) fatty acid tails attached to the glycerol backbone. The more double bonds each fatty acid possess the more unsaturated they become. Below is a picture of a generic triglyceride.

Fats can also be drawn like zig-zags, where each point is a carbon atom, and unless there are 2 lines (a double bond), the carbon is saturated with hydrogens.

            Now that you know what a general fat looks like, let’s get down to more technical things. There are different types of fat—saturated (SFA), monounsaturated (MUFA), polyunsaturated (PUFA), and trans-fatty acids. In general, we want to consume more MUFAs and PUFAs than SFAs, and if at all possible, we want to limit trans-fats to scant amounts. Saturated fatty acids mean that the fatty acid chain (the carbon molecules) are all saturated (using up the remainder of carbon’s 4 bonds) with hydrogens—therefore each carbon atom gets 2 hydrogen bonds and 2 carbon bonds, and the very last carbon gets 3 hydrogens since it only has to bond to one carbon to stay on the chain. Unsaturated fatty acids means that not all of the carbons are saturated with hydrogen, therefore leaving that extra bond to be carried over to the adjacent carbon making it a double bond. Monounsaturated fats are those where there is only one double bond in the fatty acid chain, and polyunsaturated fatty acids are those where there are many double bonds. In the zig-zag picture above, you can see a saturated fat on top, a monounsaturated fat in the middle (note: when making a double bond it also changes the structure and direction of the fatty acid chain), and a polyunsaturated fatty acid on the bottom.

             Another cool thing about the chemistry of fats is understanding why they look they way they do by seeing how they present as

the oils we see in our kitchens. SFAs stack really well with each other because they make a nice chevron pattern—because of this SFAs are solid at room temperature—think butter. However, MUFAs don’t stack very nicely, because they are bent in the middle, and usually the bend is at different parts of the chain for each fatty acid—these are liquid at room temperature, and sometimes solidify a bit in the fridge—think olive oil. PUFAs don’t stack, and are very loosely kept together—think of

stacking a bunch of randomly bent paperclips. PUFAs are liquid at room temperature and when cooled like grapeseed oil. Trans-fats are fats that were originally unsaturated fatty acids (mono or poly) but then had hydrogens pumped in causing the bend in the chain to twist. This results in a chain that mimics SFAs while still holding on to that double bond—this means trans-fats are solid at room temperature, like Crisco.

              Fats are digested starting in the mouth with mechanical digestion (chewing) and chemical digestion from lingual lipase. Next, the gallbladder releases bile and pancreatic enzymes enter the GI tract at the duodenum to further digest fats. Bile has a hydrophobic end (water hating, fat loving) and a hydrophilic end (water loving, fat hating). The bile emulsifies the fat from a large globule into small micelles (tiny fat globules surrounded by bile) by attaching its hydrophobic end to the fat droplets. Micelles can travel through the hydrophilic intestinal wall into the lymph system, travel to the liver, then get sent out through the blood in lipoproteins and delivered to cells.

So now that you have the general background—let’s talk food and nutrition. Fats are the most calorically-dense macronutrient, producing 9 calories per gram of fat. This is more than double carbohydrates and proteins who both produce 4 kcals/g. This means that in a smaller volume of food, you can have equal to or greater calorie content than a CHO or protein item. Remember my #1 lesson? BALANCE, VARIETY, AND MODERATION. Fats, contrary to popular belief, are not bad for us. We need fats in order to surround our organs for protection, for vision, skin health, and

emergency preparedness. An important thing to know when it comes to eating fat is what kind of fat you’re eating and how much of it you are eating—too much of anything can be harmful whether it’s water or doughnuts. I hate labeling foods as “good” and “bad”, so instead we are going to focus on the fats that are generally preferred over others with the understanding that a little trans-fat here and there won’t kill you.

What type of fat is preferred in our diets? We want to get a variety of all 3 types of fats (again, trans-fats as little as possible) with an emphasis on the MUFAs and PUFAs. The Mediterranean diet—the one everyone tells you is the elixir of life—consists of roughly 75% MUFAs, 17% PUFAs, and 8% SFAs. The 2015 Dietary Guidelines for Americans suggest that Americans strive to make SFAs less than 10% of their daily fat intake. What actually happens? The average American’s typical daily fat intake consists of 44% MUFAs, 23% PUFAs, and 33% SFAs—a lot different than the recommendations! Strive to use more vegetable oils than animal fats, eat fried foods in moderation, and vamp up the olive and canola oil. Also, SFAs can come in long chains, medium chain, and short chains, and for our health medium & short chain SFAs are preferred (avocado and coconut oil).

What do fats do for our bodies? Fats are responsible for helping in the absorption of fat-soluble vitamins (vitamins A, D, E, and K). These vitamins need to “hold hands” with a fat molecule in order to cross the intestinal wall. Fats create a pleasant mouthfeel and aid in the taste and texture of our foods making them desirable which has helped in the survival of our species. Fats promote healthy cell function and maintain the vitality of our skin and hair. Fats also help you feel satiated when you’ve eaten a meal, and keep you from getting hungry 15 minutes after you’ve finished—this is because they take longer to digest! Fats insulate our vital organs, so that if you bump up against something it won’t cause an organ bruise—fat is a natural shock absorber. The most known function of fat is that it stores energy and is our emergency preparedness kit. Fat is the main energy storage in our bodies, and in times of need we can unlock the door and use the energy, whether you’re purposely dieting or accidentally get lost out in the woods. Fats are essential for reproductive health signaling vital hormones to be released allowing for puberty, menstruation, and reproductive wellness. Last but not least, fat plays a role in metabolism producing coenzymes, fueling metabolic processes, and aiding in the production of ATP.

Now, go out there and have some avocado on toast, dip a piece of French bread into olive oil and balsamic vinegar, or have some fried chicken! Have fun! Enjoy the food that you eat. Fats are meant to help us, not hurt us, so go eat some food that actually tastes good!

Lindsey’s Signature Guacamole

2 Haas avocados, diced

½ jalapeno, minced

1 tomato, diced

¼ cup cilantro, chopped

½ lime, juice only

½ lemon, juice only

Combine all ingredients in a bowl, mix together, and enjoy with some chips!