Fat has long been vilified for being the cause of excess weight gain and the current epidemic of obesity worldwide. However, this has been largely misplaced and based on old and outdated science that has since been disproven. Yet many people still don’t understand why you need fat. They continue to shy away from fat and we see this in the products available in the store – fat free, low fat, skim milk, etc. Unfortunately, this often leads to foods replacing the once healthy fats with sugars and artificial sweeteners, the true causes of weight gain and many modern diseases. Fat is an essential part of a healthy diet and has been part of the human diet long before food guidelines started telling us what to eat. It plays many important physiological roles in the body.
Let’s have a look at some of the main reason of why you need fat in your diet:
Certain fats are considered “essential”, meaning that our body cannot synthesize them on its own and they need to be consumed from the diet. The two known essential fatty acids are the polyunsaturated Omega-3 and Omega-6 fats, Alpha-Linolenic Acid (ALA) and Linoleic Acid (LA) respectively. There are other Omega-3 and 6 fats that can be conditionally essential as well, meaning that in certain circumstances, they may be essential. I’m sure many of you have heard of these fats as they have gained popularity within the health and wellness community in the last decade or so in relation to controlling inflammation (see Cell Signalling).
Fat Soluble Vitamins
There are a class of vitamins which are considered ‘fat soluble’, meaning that they require fat to be absorbed and transported throughout the body. These vitamins are Vitamin A, D, E, and K. Each of these play various important roles throughout the body. Deficiency in any of these can lead to pathology and disease, most notably in the media is vitamin D and bone health. Although vitamin D is a key component, vitamins A, E, K all work synergistically to regulate bone health and many other physiological activities throughout the body.
Fat is the primary energy source in our body, providing ATP (the bodies energy molecule) during all but the highest intensities of exercise. Compared to carbohydrates which generate on average 38 ATP per molecule, fat can generate upwards of 129 to 163 ATP depending on the length of the fatty acid. Overall, the body can retain roughly 1000-2500 calories (depending on body size) worth of energy in carbohydrate whereas even a lean average size male may carry over 100,000 calories worth of energy! Clearly our bodies were meant to utilize fat over carbohydrates for majority of our energy needs which is why you need fat in your diet!
Cell Wall Constituent
Every single cell in our body is made up of fats. The membrane of the cell is composed of a bilayer of phospholipids (phosphate and fats) as well as cholesterol which maintains the fluidity of the cell and controls what enters and leaves the cell. This lipid bilayer is extremely important in regulating the health of the cell and thus the organ, organ system and organism (you).
Certain fats are the building blocks of our hormones, the signalling molecules that regulate everything from our growth, our metabolism and even our psychological state. Of key importance is cholesterol – it is the backbone in the synthesis of our sex hormones; testosterone and estrogen being the most widely known. Vitamin D is also considered a hormone as it acts to regulate cell signalling, and as we learned above, Vitamin D requires fat for its proper functioning.
Brain and Myelin Sheath
The brain and nervous system is comprised of a vast amount of fat. Nearly all the nerves that run through your body that signal everything from conscious sensations and the unconscious control of your heart are covered in a sheath of fat. This cover is called the Myelin Sheath. This fatty protective cover allows your nerves to conduct signals far faster than if they did not have it. Fat also plays a vital role in protection and insulation of the brain and nervous system. Recent studies have shown that fats can play a protective role in preventing neurodegenerative diseases1. Yet another reason for why you need fat in your diet.
Another major role of fats is cell signaling, how each and every cell throughout your body communicates and orchestrates its fine physiological controls. Various polyunsaturated fats help form what are known as the eicosanoids. These molecules are important in cell signalling of various kinds, including inflammation and immune responses. Much of the talks about Omega-3 and 6 are closely related to how these affect eicosanoid homeostasis (balance) in the body.
Hopefully by now, you can see why you need fat in your diet and why it is essential that you continue to eat healthy natural fats. If your diet is deficient in these, then all the processes mentioned above may suffer and thus your overall health may suffer. For more information on fat physiology and healthy fats, Dr. Mark Hyman has released a fantastic book on fats titled Eat Fat Get Thin, which you can find here.
Richard Game: BKin(Hons), Nutritionist, Holistic Health Coach, Strength & Conditioning Coach. Founder of The Primal Way
- Sanders R. Can some types of fat protect us from brain disease? Berkley News [Internet] 2016 [cited 2017 Jan 21] from http://news.berkeley.edu/2016/09/08/can-some-types-of-fat-protect-us-from-brain-disease/