Nutrition FAQs: What's the role of fats in the body?
Angela Wright, RHN
Are you aware of the role of fats in the body? In the last instalment, we walked through the different types of fat. We also busted some common myths about the effect of certain dietary fats on our body. This time, let's chat about all the different things fats are in charge of - from keeping our cells in check to producing energy. Let's dive right in!
Q: So what do fats do in the body again?
A: Fatty acids (what we commonly refer to as fats) are one of the three macronutrients that the body needs to ingest in order to properly function. For instance, every one of our trillions of cells require fats as an integral part of the cell membrane. The right fats let nutrients in and wastes out of the cell. They are also required for proper communication between cells. We make over 200 billion new replacement cells every day, all of which require healthy fats to make their membranes super functional. That’s just one of their many roles. The body requires them for manufacturing sex and stress hormones, maintaining your brain, regulating blood sugar and pain response, immune system functioning, controlling inflammation and carrying fat-soluble vitamins like vitamins A, D, E and K. They are also an excellent energy source, once you’ve used up your carbohydrates.
Q: How do I use fat as an energy source?
A: Fats are an excellent source of clean energy that you can tap into when your carbohydrate energy and stores are used up. Fasting depletes those carbohydrate stores (known as glycogen), switching you into fat-burning mode. You can use your stored fats, or use those you get from your diet. One of the easiest-to-use fats are medium-chain triglycerides (MCTs). They travel directly through the portal vein to the liver. Here, they can be directly used for energy as ketone bodies. Ketone bodies are a form of energy that can be used as an alternative fuel when carbohydrates and blood sugar levels are very low. You do this without any aid from insulin, helping with blood sugar regulation challenges. Ketones can also cross the blood brain barrier, fueling the energy-intensive brain. Using ketones for energy helps the body to also burn adipose fat for fuel as well; the foundation of the ketogenic diet. You can also use these fats when you are not in ketosis for a slow, steady energy source. That way, you can forgo the peaks and crashes that can come with a refined carbohydrate diet. Coconut is an excellent source of MCTs. It does however also contain many long-chain saturated fats, so separating out the MCTs allows your body to use the fats in this direct-to-liver pathway.
Q: How do I know if I’m digesting my fats properly?
A: First, let’s talk about how we digest the fats that we eat. Fat digestion happens in the small intestines. Bile (made in the liver, housed in the gallbladder) and lipase enzymes (made by the pancreas) are an essential part of the equation. They're required to break fats down for transport out of the digestive system. Long-chain triglycerides then travel through the lymphatic system, whereas short- and medium-chain triglycerides travel directly through the portal vein to the liver. If your dietary fats don’t get digested and absorbed, you may have feelings of fullness, diarrhea or stools that float in the bowl. You may also suffer from emotional or hormonal imbalances, or brain, immune, inflammation and blood sugar issues - so many symptoms can be due to not eating or absorbing enough good fats.
Q: What happens when I don’t get enough good fats in my diet?
A: Not enough good fats in the diet means the body is scrambling to make do with whatever fats you are eating. If it runs out of raw materials to work with it will not be able to fulfill some of its functions properly. Cellular function and repair suffer. Hormones are unable to properly fill their roles - potentially leading to imbalances. This includes PMS, menopausal symptoms, infertility, anxiety, depression and chronic inflammation. Behavioural issues, mood disorders and mental health challenges can all be contributed to by insufficient healthy fats in the diet. Immune function suffers, pain is more painful, the cardiovascular system takes a blow. All over, not a great place to be. Fats in a meal also tell you when you’re full. You have little sensors in your stomach that sense fat, which triggers satiety hormones. This helps to control your appetite. Without dietary fats, the body also thinks it's starving for fats. It will hold on to any energy it can (usually from refined or excess carbohydrates) and store it as body fat. Skipping fats in your meals is doing the opposite of what those years of fat-free fad diets promised!