On the surface, carbohydrates are a quick, often fast and inexpensive form of nutrition to power through each day. Think about all those grab-and-go snacks we associate with breakfast—granola bars, fruit-filled smoothies, muffins. We start our mornings with carbs, and we keep piling them on as the day progresses.
Just because something works doesn’t mean it’s the most efficient means. The tissues and cells that make up our bodies need energy to perform everyday functions to keep us alive. There are two primary sources from which they can draw energy from the foods we eat. One form of energy is carbohydrates, which convert to glucose. That is the current model that most of us follow. There’s an alternative fuel, though, and a surprising one: fat. Yes, the very thing you’ve been told to limit your entire life might just be the resource you need to jump-start your metabolism. Organic compounds, called ketones, are released when our bodies metabolize food and break down fatty acids. Ketones act as energy to keep our cells and muscles functioning.
You’ve likely heard the word “metabolism” throughout your life, but do you know what it means exactly? The term simply refers to the chemical reactions required in any living organism to stay alive. Of course, our metabolism is anything but simple given the complexities of the human body. Our bodies are constantly at work. Even when we’re sleeping, our cells are continually building and repairing. They need to extract the energy from within our bodies.
Glucose, which is what carbs are broken down into once we eat them, is one way to fuel our metabolism. Our current nutrition guidelines focus on carbs as the primary source of energy. Factor in any additional sugars we eat and the recommended daily servings of fruit, starchy vegetables, grains, and plant-based forms of protein (e.g., beans), and there’s no lack of glucose in our bodies. The problem with this model of energy consumption is that it leaves us like hamsters running on one of those wheels. We’re burning energy but getting nowhere, especially if we’re consuming more carbs than our bodies can use in a day’s work.
But there’s that other form of energy I mentioned: fat. How does that work exactly? Is it possible that tapping into that alternative fuel source will help our bodies burn energy more efficiently, with greater overall benefit to our health? We’re back to that old idea of you are what you eat, except now think about the principal theory instead as you burn what you eat. That’s where ketosis comes into play. Switching to a high-fat, moderate-protein, low-carb diet allows your body to enter a state of ketosis, wherein you metabolize fat, triggering a release of ketones to fuel the functions of our elaborate inner workings. The liver releases ketones after fatty acids are broken down.
Achieving a state of ketosis is about balance, but not the kind you’re used to when it comes to eating. It turns out that our current food pyramid, which instructs us to consume an inordinate amount of carbohydrate-rich foods for energy, is upside down. A more efficient plan for fueling your body has fats at the top, making up 60 to 80 percent of your diet; protein in the middle at 20 to 30 percent; and carbs (really glucose in disguise) way at the bottom, accounting for just 5 to 10 percent of your daily eating plan.
KETO VS. PALEO
Evolution offers us many benefits. The ability to use fire and electricity to cook our food is proof alone that progress can be a good thing. Somewhere between our hunter-gatherer foraging lifestyle and today’s modern world, a big disconnect happened. Sure, we have longer life spans now, but what about the quality of those extra years from a health perspective? The sluggish feeling that never seems to go away may be not just because you need to get extra sleep (though sleep is always a good thing!).
If food is fuel for our bodies, then it’s safe to say that what we eat has an impact on our productivity. Put diesel in a car designed to run on gasoline and the effects are disastrous. Is it possible our bodies are in a similar state today, the result of our systems’ having evolved to rely on carbs for energy as food became more reliably available, instead of fat, as in our early days of existence? I realize this sounds an awful lot like advocating for a paleo diet, but while the ketogenic lifestyle looks similar, the underlying principle to keto is vastly different. Keto is about creating a synergy between what you eat and the way your body functions—that’s why the focus is on a specific manipulation of macronutrients (fat, protein, carbohydrates, fiber, and fluids). Every calorie is made up of specific macronutrients. Understanding why you’re making such specific food choices is key to comprehending the bigger picture.
Fiber, for example, keeps us regular because it helps food pass through the digestive system. What goes in must come out, and fiber is essential to that process. Protein aids in tissue repair, producing enzymes and building bones, muscles, and skin. Fluids keep us hydrated—without them, our cells, tissues, and organs cannot function properly. Carbohydrates’ primary role is to provide energy, but to do so, the body must convert them into glucose, which has a ripple effect throughout the rest of the body. Carb consumption is a delicate balance for people with diabetes because of its relationship to insulin production from increased blood sugar levels. Healthy fats support cell growth, protect our organs, help keep us warm, and have the ability to provide energy, but only when carbohydrates are consumed in limited quantities. I’ll explain more about why and how that happens shortly.
CARBS VS. NET CARBS
Carbohydrates exist in some form in almost every food source. Total elimination of carbs is impossible and impractical. We need some carbohydrates to function. It’s important to know this if we want to understand why some foods that fall into the restricted category on a keto diet are better choices than others.
Fiber counts as a carb in the nutritional breakdown of a meal. What’s important to note is that fiber does not significantly affect our blood sugar—a good thing, since it’s an essential macronutrient that helps us digest food properly. By subtracting the amount of fiber from the number of carbs in the nutritional tally of an ingredient or finished recipe, you’re left with what’s called net carbs.
Think about your paycheck before taxes (gross), and after (net). A terrible analogy, perhaps, since no one enjoys paying taxes, but an effective one in trying to understand carbs versus net carbs and how to track them. You put a certain number of carbs into your body, but not all of them affect your blood sugar level.
This doesn’t mean you can go crazy with whole-grain pasta. Even though it’s a better choice than white-flour pasta, overall, you should be limiting your net carbs to 20 to 25 grams per day. To put that in perspective: two ounces of uncooked whole-grain pasta have about 35 grams of carbohydrates and only 7 grams of total fiber. Probably pasta and bread are the two main things that people will ask you if you miss. Best way to answer them is by sharing all the things you can eat (see the Keto Cheat Sheet here).
HOW LONG DOES IT TAKE FOR KETOSIS TO KICK IN?
Most people transition into ketosis within one to three days. It can take some people a full week, as all bodies are different. Factors that affect how quickly you enter ketosis include your current body weight, diet, and activity level.
In order to enter ketosis, your body needs to first burn through its glycogen (glucose) supply. Once the glycogens are depleted, your body signals it’s time to start breaking down those fatty acids. During the next few days, the liver gets the message to begin excreting ketones. This last part of the process signals that you’re in ketosis. The early stage is a mild ketosis, as ketone levels will be relatively low until you maintain ketosis for a steady period of time. You can measure ketone levels formally, but you might start to notice some physiological changes that show you’re in ketosis, such as keto flu or keto breath. They are not as severe or dramatic as they sound, and the benefits of ketosis might outweigh the downside in this phase-in period toward your defined goals, but it’s good to familiarize yourself with the symptoms nonetheless (Keto flu)