Keto has a lot of research to back up its efficacy, but every now and then the carb-avoidant diet still gets called into question. There's a long-held belief that the human body requires carbohydrates in order to function. The popular "rule" that states our diets must be 45 - 65% carbs isn't actually a rule -- it's a myth.
Because carbs are traditionally a huge part of everyone's diet, this belief seems particularly stubborn and hard to shake for most people. How is it possible that we don't need carbs when carbs are in just about everything?
Our bodies have built-in processes that enable normal functioning during times of low to no carbs, and these processes are sustainable in the long-term. We're basically marvels of engineering, finely-tuned powerhouses where chemical reactions take place to ensure our survival and well-being. Certain chemical reactions, like gluconeogenesis and glycolgenolysis, kick in and take over when we kick carbs out.
Many people will never get to consciously activate and experience/experiment with these processes (due to lifetime of carb consumption), so they'll remain unaware of the power their own bodies have self-regulate and thrive without carbs. Let's look at the science and terminology behind some of the amazing processes that power the ketogenic body.
First, we'll do a brief rundown of conventional carb metabolism and why it leads to weight gain.
Glucose from Carbs, the Usual Suspects
Glucose is a type of sugar we need for energy. It can be, and often is, obtained by eating carbohydrates. Our carb-heavy meals get broken down into glucose by the digestive system. The glucose is then released into the bloodstream where it undergoes several rapid chemical changes in order to provide cells with immediate energy. Because glucose is carried throughout the body by the bloodstream, it's also known as blood sugar.
Insulin, a hormone produced by the pancreas, gets released in response to the amount of glucose in the blood. If there is excessive glucose that doesn't get immediately used up as energy, it reacts with insulin in a process called glycogenesis.
Glycogenesis creates glycogen, which gets stored in the liver and muscle cells for use as energy later on. Excess glucose also gets converted into fatty acids which get carried throughout the body (with the help of insulin) and become adipose tissue: body fat.
It almost goes without saying that when it comes to carbs, its very, very easy to eat too much.
High blood sugar and weight gain are natural consequences of regular carb consumption. But will our blood sugar drop to dangerously low levels if we stop? Will we deplete our energy and fat stores to the point of starvation?
Glucose from Fats and Proteins, the Keto Way
We do indeed need a certain amount of glucose for survival. This is why blood sugar regulation is so vital and why blood sugar disorders can be deadly.
Despite the fact that we've likely been maintaining our blood sugar levels with carbs for most of our lives, we don't actually need carbs to reach healthy glucose levels. A myriad of experiments in fasting and carb-cutting have proven that the human body will make glucose available through a couple of elegant processes, glycogenolysis and gluconeogenesis.
Glycogenolysis forms glucose from glycogen stored in the liver. It steadily generates a "low but significant amount of glucose."
Gluconeogenesis is the creation of glucose through the breaking down of lactic acid (a metabolic byproduct), triglycerides (fat), and amino acids (proteins).
There we have it! We only need fats and proteins -- the keystones of Keto -- to produce the glucose we need.
These two processes work for us during periods of fasting and even while sleeping. Since ketosis closely imitates the effects of fasting without actually having to fast, they're our good friends on the Keto diet.
But What About the Brain?
Most of us are accustomed to our brains running on glucose. It's true that a portion of our brains -- about 30% -- can only function with glucose as fuel. But about 70% of the human brain can function perfectly on ketones (the compounds the body produces for energy when in ketosis). When on the Keto diet, gluconeogenesis comes to the rescue to provide glucose to the parts of the brain that need it. Ketones, which take care of the marjority of the brain, are a more efficient fuel.
There's a good deal of evidence to shows that after an initial adjustment period, the brain might actually function better on ketones than on glucose. People report improvements in mood and general levels of clarity and alertness. For people who suffer from migraines and seizures, ketosis reduces their prevalence. Ketones also seem to increase the number of mitochondria in the hippocampus, which can improve learning and memory. Ketones in the brain seem to lead to greater neural stability in general.
"The Body Needs Carbs to Survive ..." Sounds Like the Carbs Talking
Without carbs, our brains may actually function better. In ketosis, we "teach" our bodies to produce a stable amount of glucose, lowering the risk of hypoglycemia and regulating our appetites.
Exercise is also entirely possible! Conventional advice tells us to load up on carbs before exercising, but the body is more than capable of enduring a good workout without them. If we carb bomb beforehand, we don't end up burning fat and losing weight efficiently. Most carb-shy people feel best doing sustained workouts, like a long run or swim, instead of short bursts like sprinting or lifting.
There's no universe in which we absolutely need to keep eating carbs to look and feel like the best version of ourselves. So, stay under those limits and enjoy the results!