When we talk about eating keto, we’re talking about eating fat. Like, a lot of fat. Probably more than you’ve ever dreamed of eating, and then about 10 % more than that.
But before we get to how and why that works, let’s run through the basics. Fat, protein, and carbohydrates are all macronutrients, or “macros,” and they make up the bulk of our food. (The rest is micronutrients—vitamins and minerals that are essential for health.)
Carbohydrates are most abundant in grains and sugars—bread, pasta, rice, corn, quinoa—but fruits and vegetables also contain carbohydrates, especially starchy vegetables like potatoes and sweet potatoes and high-sugar fruits like bananas. Proteins are found in animal foods like eggs, beef, fish, chicken, and turkey and in moderate quantities in some plant foods, such as beans, lentils, nuts, and seeds. Fats are abundant in coconut oil, avocados, olives, nuts, and seeds and animal foods such as ribs, steak, bacon, and dairy.
I used to be a low-fat, high-carb vegan. I remember exactly how little fat I ate and how scared I was of it. I’m guessing that many of you are right there with the old me. But if what you’re doing isn’t working, you’re in a fine place to try something new. Something like the keto diet.
When I first saw the word keto, I was totally intrigued. It sounded foreign, somewhat rebellious. And as you’ll read further on, I love being rebellious, so I was instantly hooked. Keto is short for ketogenic, an eating style that reduces carbohydrate intake, increases fat intake, and moderates protein intake in order to achieve a metabolic shift known as ketosis.
Right now you are burning glucose for energy (unless you’re eating ketogenic already, in which case, total win!). Your body is primed to use energy from the limited glucose in your body, so when that starts to get used up, you become hungry and need to eat again. When I was a glucose burner, I ate every three hours, and the word hangry was at the top of my personal dictionary. I packed snacks to take with me, worried about where my next meal would come from, and would (lightly) budge people in line if it meant I’d get food sooner. Food ruled my life.
What the ketogenic diet does is switch the body from burning glucose to burning fat. This is the primary source of fuel for the body, it’s known as being in ketosis. Now that I’m in ketosis, my daily energy requirements are primarily met by burning fat, so I don’t need to get glucose from the bread, cookies, dried fruits, and treats I used to eat constantly.
My body doesn’t need glucose to survive, and yours doesn’t either! I’ve jumped off the roller coaster of blood sugar highs and lows, and I’m living the good life free from constant snacking, epic weight gain, and uncontrollable cravings. You can, too! There’s tons of room at the keto table for you. Pull up a seat!
Ketosis is not Ketoacidosis
When we talk about being a fat burner, we’re talking about nutritional ketosis, not ketoacidosis. Ketoacidosis is a dangerous condition experienced by diabetics when blood glucose and ketones rise to extremely high levels at the same time. A ketogenic diet won’t get you even close to the levels of ketones that diabetics can experience in ketoacidosis. In fact, if you do not have diabetes, it’s virtually impossible for you to go into ketoacidosis. Even a trace amount of insulin will keep ketone levels in the safe zone.
The level to which carbohydrate intake has to be reduced in order to get into ketosis varies greatly from person to person depending on enzymatic processes, stress level, heritage, and more. (We’ll get into the nitty-gritty of macro ratios and how you know when you’re in ketosis in the next couple of chapters.) But regardless of where you’re coming from, even if you don’t want to go balls to the wall, I’ll outline how you can benefit from increasing your fat intake and dance on the edge of ketosis without macro and calorie tracking running the show.
There are many forms of ketogenic eating. I’m going to be introducing you to the whole-food-based form that’s rich in health-promoting foods and fats. Think of it as a Paleo eating style, jacked up on fats and with way fewer sweet potatoes and chocolate treats and way less maple syrup. You will radically lower your carbohydrate intake, massively increase fat, and moderate protein, a triple whammy that triggers your body to start burning fat for energy rather than glucose.
What Happens in Your Body When You Eat Keto
To explain why the keto diet is so great for health, I want to start by explaining how the body functions on carbohydrates—which is probably the way your body is functioning right now. Carbohydrates from any source—fruits, vegetables, grains, sugars, anything starchy—are broken down into glucose, which is used for energy.
When you have more glucose than you need immediately, your body stores the excess in the liver and then the muscles as glycogen. This is the body’s first-line energy stockpile of fuel for short-burst physical efforts and for keeping certain systems (the brain, red blood cells, kidney cells) running efficiently all day. The glycogen stores in the liver can be utilized by the rest of the body, but the glycogen in muscles is reserved for action in that particular muscle. When space for glycogen in the liver and muscles is full, glucose is converted to fat.
Glucose is the first source the body goes to when it needs energy. But because we can store only a couple thousand calories of glucose (or glycogen when it’s stored) at any given time, it’s not a sustainable source of energy. Also loosing weight is not just about calories. That means we need to keep replenishing it by eating constantly throughout the day. And relying on glucose can prevent us from stabilizing our blood sugar, which spikes when we eat and then drops, resulting in endless cravings and overall weight gain. In addition, glucose can be converted to not just stored fat but also triglycerides in the blood, which can be a risk for heart disease. You’ve also probably heard a lot about insulin, insulin resistance, and insulin sensitivity—all can be negatively impacted when relying on glucose for fuel.
Insulin is the hormone that balances blood sugar; it triggers the absorption of glucose by the liver, fat, and muscle cells and thereby lowers the level of glucose in the bloodstream (blood sugar). Insulin also pauses any fat-burning that’s going on so that we can burn or store the glucose that’s coming in. Once glucose is handled, insulin levels drop and we go back to burning fat. Insulin also alerts the brain if we’re in need of fuel, which triggers hunger signals. When we have good insulin sensitivity, all of these processes work perfectly, maintaining healthy blood sugar stability. But problems arise when glucose levels in the blood are constantly high.
The correspondingly high levels of insulin cause the insulin receptors on cells to become deaf to insulin. Think of the boy who cried wolf: he cries and cries, so all the townspeople stop listening to his warnings. In the case of insulin resistance, cells no longer listen to insulin’s instruction to absorb glucose, so glucose levels in the bloodstream can get and stay too high. But when things are functioning as they should, when the concentration of glucose in the bloodstream falls too low, a hormone called glucagon is released. It stimulates the liver to convert stored glycogen into glucose, which is then released into the bloodstream. It also tells the body to start using the stored fuel source, fat.
Burning fat for fuel is called lipolysis; technically, during lipolysis, fatty acids and glycerol molecules are moved from fat cells and metabolized to generate energy. As it burns fat, the body creates ketone bodies. When we’re in ketosis, these ketone bodies become what carbs are to you right now, your primary fuel. The brain can use ketones, as can skeletal muscles, the liver—the list goes on. In fact, the heart prefers ketones to glucose. That’s not to say that the body doesn’t need glucose at all. Red blood cells, for instance, require glucose, and so does the brain (although a certain amount of its energy requirements can be met by ketones). But the body can actually create glucose on its own through a process called gluconeogenesis.
In gluconeogenesis, the liver turns amino acids—the building blocks of protein—and fatty acids into glucose. There’s no need to eat carbohydrates to get glucose! It can be challenging to make the switch from preferring glucose as the primary fuel to preferring fat because the body isn’t entirely accustomed to using fat. It has to ramp up the processes needed to metabolize fat until it finally is able to prefer fat to glucose as a fuel source—a process that’s known as “fat adaptation” or “becoming fat-adapted.” Once you’re in nutritional ketosis and burning fat as your primary fuel, blood sugar and insulin levels drop and levels of HDL (good) cholesterol increase.
Your body starts to burn its stored fat along with dietary fat, which means that you start to lose weight—and, even better for your health, the visceral fat around your vital organs, which is linked to increased risk of heart disease and type 2 diabetes, shrinks. And remember how insulin alerts the brain if fuel is running low, resulting in hunger? Because insulin is stable on a ketogenic diet and the fuel we need (fat) is right on our bodies, appetite is reduced naturally.
In addition, studies show that nutritional ketosis can be therapeutic for many of today’s widespread chronic health problems, such type 2 diabetes, irritable bowel syndrome (IBS), polycystic ovary syndrome (PCOS), Alzheimer’s disease, and dementia. On a day-to-day basis, people in ketosis often report the following changes in their health:
- Effortless weight loss
- Reduced appetite
- Improved mood
- Ability to eat more without gaining weight
- Lower and more stable blood sugar
- Fewer cravings
- Lower blood pressure
- Clearer thoughts
- Improved sleep
- Reduction in gas and bloating