Without energy you could not survive. Your cells would starve and all of the physiological processes in your body would cease. So what is energy exactly and where does it come from? Your body uses several different metabolic pathways to convert the food you eat into useable energy. The default metabolic pathway uses the glucose from carbohydrates as fuel. As long as you provide your body with carbohydrates, it will use them as energy, storing fat in the process. When you deny your body carbohydrates, it has to turn somewhere else to get the energy it needs to live.
Why Fat Is Your Friend
Fat is an integral part of every cell in your body. This macronutrient is a major component of your cell membranes, which hold each cell together. Every single cell in your body, from the cells in your brain to the cells in your heart to the cells in your lungs, is dependent on fat for survival. Fat is especially important for your brain, which is made up of 60 percent fat and cholesterol.
Fat and cholesterol are used as building blocks for many hormones, which help regulate metabolism, control growth and development, and maintain bone and muscle mass, among many other things. Fat is vital for proper immune function, helps regulate body temperature, and serves as a source of protection for your major organs, surrounding all of your vital organs to provide a sort of cushion for protection against falls and trauma. It also helps boost metabolic function and plays a role in keeping you lean.
Fat is classified as an essential nutrient, which means that you need to ingest it through the foods you eat because the body cannot make what it needs on its own. Fat is composed of individual molecules called fatty acids. Two of these fatty acids, omega-3 fatty acids and omega-6 fatty acids, are absolutely essential for good health. Omega-3 fatty acids play a crucial role in brain function and growth and development, while omega-6 fatty acids help regulate metabolism and maintain bone health. Fat also allows you to absorb and digest other essential nutrients, such as vitamins A, D, E, and K and beta-carotene. Without enough fat in your diet, you wouldn’t be able to absorb any of these nutrients and you would eventually develop nutritional deficiencies.
Fat is also a major source of energy for your body. Because each gram contains 9 calories, fat is a compact source of energy that your body can use easily and efficiently. Unlike with carbohydrates, which your body can only store in limited amounts, your body has an unlimited ability to store fat for later use. When food intake falls short, such as between meals or while you’re sleeping, your body calls on its fat reservoirs for energy. This physiological process is what the entire ketogenic diet is based upon.
How Your Body Obtains Energy
Energy cannot be created. It can only be converted from one form to another. Because of this, your body needs to get energy from somewhere. It uses the food, and the macronutrients from the food, that you eat. The biochemical process of obtaining energy is a complicated one, but it’s important to understand the basics so you can get a feel for how ketosis works on a cellular level.
Energy from Carbohydrates
Although your body is adept at using any food that’s available for energy, it always turns to carbohydrates first. When you eat carbohydrates, they are ultimately broken down or converted into glucose, which is absorbed through the walls of the small intestine. From the small intestine, glucose enters into your bloodstream, which naturally causes your blood glucose levels to rise. As soon as the glucose enters your blood, your pancreas sends out insulin to pick it up and carry it to your cells so they can use it as energy.
Once your cells have used all the glucose they need at that time, much of the remaining glucose is converted into glycogen (the storage form of glucose), which is then stored in the liver and muscles. The liver has a limited ability to store glycogen, though; it can only store enough glycogen to provide you with energy for about twenty-four hours. All the extra glucose that can’t be stored is converted into triglycerides, the storage form of fat, and stored in your fat cells.