Under "normal" physiological conditions, we tend to fuel a significant portion of our metabolism, particularly the energy needs of our brains, from carbohydrates. I put "normal" in quotation marks because the frame of reference for studying our metabolism is our modern, consistently overfed world. This overfed state is not, in fact, normal, healthy, or optimal, as the genetics governing our metabolism were forged in an environment in which access to food was inconsistent and the activity level to procure this food was reasonably high.
If the brain can only run on glucose (as most health care providers claim), we must have a consistent supply of dietary glucose or we will "bonk" (experience serious cognitive problems due to low blood sugar) and cannibalize the proteins in our body to produce glucose for the brain.
Fortunately for us, biology figured out an elegant solution to the problem of inconsistent food sources and a large, hungry brain: ketosis.
What is it and why is it the answer? The ketogenic diet is a high-fat, low-carb style of eating (typically 30 to 50g of carbs per day, not counting fiber) with moderate to low protein (between 75 and 100g per day). When we are either fasting or eating at a significant caloric deficit, our body tends to mobilize our stored body fat for energy. If carbohydrates and proteins are sufficiently limited, fat enters our mitochondria (specifically in the liver) in large amounts. Without sufficient glucose (or protein), our bodies shift into the process of ketosis. Ketosis takes the high-energy fat molecules stored in our bodies and converts them to a form that can fuel the heart, muscles, organs, and, perhaps most important, the brain. This provides an almost limitless supply of brain-friendly fuel in the form of ketones while decreasing the need for our metabolism to use our muscles and internal organs to produce glucose. If we think about this, it’s really smart engineering. If we have to go for extended periods without food, we need to feed the brain, but we do not want to lose an enormous amount of protein from our muscles and organs to keep blood glucose levels consistent. Ketones provide an alternate fuel for the brain and body while making small amounts of glucose from fats.
A healthy metabolism should be able to shift seamlessly between fat and glucose as a primary fuel source.
For most people, embarking on a period of fasting or a ketogenic diet can be pretty rough in the beginning. This is not the way it should be. If we are insulin sensitive and generally healthy, we should be able to weather these transitions with just a bit of discomfort. Our modern world of easily accessible, hyperpalatable foods has hijacked this process and keeps us perpetually on one side of this dynamic process, leaving us inflamed and insulin resistant. Ketosis and fasting may prove to be some of the most powerful tools in our collective medical kits but should be used with respect.
If you do decide to give ketosis a try after transitioning in low-carb eating with my 30-Day Reset and 7-Day Carb Test Plan, here are some meals from my book, Wired to Eat, to get you started:
Creamy Chicken and Vegetables
Serves 4 to 6
- 2 tablespoons olive oil, coconut oil, or other cooking fat
- ½ onion, diced
- 2 cups mushrooms, sliced
- 2 garlic cloves, minced
- 1½ pounds chicken (breast or thighs)
- 1 pound zucchini or yellow squash, cut into half-moons about ¼ inch thick
- 1 cup coconut milk
- ½ cup chicken stock
- 2 cups fresh spinach
- ¼ cup loosely packed fresh basil leaves, chopped
- In a large skillet or frying pan, heat the olive oil over medium-high heat. Add the onion and sauté for 5 minutes, or until softened and slightly browned.
- Add the mushrooms, garlic, and chicken and cook, stirring, for about 5 minutes more, until the mushrooms are slightly softened and the chicken is browned on the exterior.
- Stir in the zucchini, coconut milk, stock, spinach, and basil; cover and simmer for 10 minutes, or until the chicken is cooked through.
Pork Cutlets with Cauliflower Medley
Serves 3 to 4
- 1 tablespoon coconut oil, olive oil, or ghee
- 1 pound pork cutlets or pork chops, ½ inch thick or less
- Salt and black pepper
- 1 yellow onion, sliced
- 2 garlic cloves, minced
- 1 tablespoon chopped fresh rosemary
- 1 cup sliced mushrooms
- ¼ cup sun-dried tomatoes, soaked in ½ cup boiling water
- 4 cups cauliflower florets
- 1 cup full-fat coconut milk
- In a large skillet, heat the coconut oil over medium-high heat.
- Liberally sprinkle the pork chops with salt and pepper. Add the chops to the skillet and brown for 3 to 4 minutes on each side to create a nice brown crust. Transfer the chops to a plate.
- Reduce the heat to medium and add the onion to the pan, stirring to scrape up any of the browned bits from the chops. Stir in the garlic, rosemary, and mushrooms. Cook for 3 to 5 minutes more.
- Add in the sun-dried tomatoes, cauliflower florets, and coconut milk. Place the pork chops on top of the cauliflower; cover and simmer for 10 minutes, or until the cauliflower is softened and cooked through. Serve the pork chops alongside or on top of the cauliflower.