Ketosis. Ketogenic. Ketones. Keto.

You’ve probably heard some or all of these words recently, in various contexts—but what do they mean? What is ketosis? And what, exactly, is the ketogenic (or keto) diet? What are the benefits of ketosis? Is a ketogenic diet for you? Is keto interchangeable with Paleo? With all the buzz from the Paleo community regarding keto in recent years, we wouldn’t fault you if you assumed that keto was Paleo 2.0.

Put simply, a ketogenic diet is a high-fat, moderate-to-low-protein, very low-carbohydrate diet. More specifically, the technical ketogenic diet is composed of a 4:1 ratio (by weight) of fat to protein-plus-carbohydrates. To put that into perspective, someone consuming 2000 calories a day would need 200g of fat and 50g of a combination of protein and a small amount of fibrous carbohydrates. This macronutrient combination is used for the primary goal of entering the metabolic state of ketosis, defined as a rise in blood ketones. This state mimics many aspects of fasting where glucose intake is limited and insulin release is decreased. Insulin is a powerful anabolic hormone that acts as a metabolic switch. A sustained suppression of insulin release can “flip the switch” from glucose metabolism towards fatty acid and ketone metabolism, causing ketosis, leading to effortless weight loss, improved cognitive function, and numerous disease-fighting benefits. It’s important to note that ketosis is not the same as ketoacidosis, which is a dangerous complication of type 1 diabetes.

But of course, like all things diet- and health-related, there’s so much more to keto than just a strict definition.

Keto: The Definitive Guide — A Paleo Magazine Special Issue

This special issue of Paleo Magazine explores every facet of keto, including how ketosis works, what to eat on a ketogenic diet, how to modify keto for your circumstances (whether you’re pregnant, an athlete, vegetarian, or have some other specific need), and how to harness the power of ketosis for weight loss, performance, brain health, and cancer treatment. In addition to in-depth articles from the world’s preeminent experts on ketosis (including Dr. Dominic D’Agostino, Chris Kelly and Dr. Tommy Wood from Nourish Balance Thrive, Mark Sisson, Dr. Sarah Ballantyne, Dr. Joseph Mercola, Robb Wolf, and more), this issue contains detailed charts, infographics, product reviews, and over 20 beautifully photographed keto recipes.


What Is the Ketogenic Diet?

The ketogenic diet is a food regimen that shifts the body from burning carbohydrate-based fuel to burning fat-based fuel, and it comes with a surprising number of health benefits. Overall, the food eaten on a keto diet is very low in carbs and high in fats. Though it easily overlaps with Paleo, it is distinctly different.

Decreasing carbs until your body burns fat, or “going keto,” may be the newest nutrition trend, but its history dates back to the 1920s. Fasting had long been a treatment for seizures in early medical practice, but it was the introduction of a nutrition plan that mimicked the effects of fasting that had the most influential and lasting effect on seizure frequency.

How does this fasting-with-food protocol work?

The ketogenic diet shifts the substrate for the body’s daily metabolic processes. The human body typically uses carbohydrate—specifically, glucose—as its primary source of fuel. This is glaringly obvious in the case of the sugar- and grain-filled Standard American Diet, but a Paleo diet does not automatically align with a ketogenic diet either. No matter whether your day begins with bagels and Frappuccinos or a homemade sweet-potato frittata, a diet that includes ample carbohydrate is not ketogenic.

A ketogenic diet may be adapted for a variety of nutritional and caloric needs, as well as a variety of “diet approaches.” Whether your preferred method of eating is intuitive or by-the-numbers, the ketogenic diet can be crafted to fit your physiology and your personality

The ketogenic diet is built upon a foundation of dietary fat, with protein and carbohydrate filling in calorie and macronutrient needs depending on the individual. When administered as a part of a medical nutrition therapy protocol, most ketogenic diets maintain a 4:1 ratio of fat calories to combined protein and carbohydrate calories. This makes for a strict, very high-fat, very low-carb diet plan, where 80 percent of calories come from fat, protein calories are calculated using bodyweight, and carbohydrate fills in the remaining calorie requirements.

One method that is gaining popularity in the clinical setting is a “modified Atkins” approach, in which calories are not restricted or measured and carbohydrate is limited to 10-20 grams per day. The ratio of fat to combined protein and carbohydrate calories is approximately 1:1, making this approach more manageable for populations who aren’t accustomed to weighing and measuring foods.

When fat replaces glucose as the primary fuel source, the body produces ketone bodies. This occurs in the Krebs Cycle, also knowns as the Citric Acid Cycle, an energy-generating process that occurs in the mitochondria of cells.

The switch from erratic sugar-based energy to steadier, slow-burning fat-based energy sources has myriad benefits: balanced blood sugar levels, sustained energy, improved cognitive function, mood regulation, and increased efficiency in heart and brain tissue. Research has observed that ketone bodies offer therapeutic benefits to damaged or diseased brains.

Why Go Keto?

Shifting to ketosis has a myriad of surprising effects on the body’s health. Pursuing ketosis may be beneficial for populations struggling with blood sugar regulation, insulin resistance, or metabolic syndrome. Anecdotal evidence suggests polycystic ovarian syndrome may also be improved by a ketogenic protocol, and current medical research is investigating the impact of the ketogenic diet on neurological disorders like Alzheimer’s disease, Parkinson’s disease, and traumatic brain injury.

There are few people, however, who should not attempt a ketogenic diet:

    • Patients with inborn errors of fat metabolism should strictly avoid ketosis.
    • Pregnant women have altered macronutrient metabolism during gestation, and as such should not attempt a keto protocol.
    • Breastfeeding women may experience reduced lactation on a ketogenic diet and may want to avoid ketosis or consider supplementing with larger doses of starchy carbohydrate while breastfeeding.
  • Underweight women may experience adverse hormonal or fertility-related effects, and a ketogenic diet should not be undertaken until a healthy, stable weight is achieved.

As always, if you have a chronic disease and think you may benefit from a ketogenic diet, it is best to attempt the protocol under the supervision of a trained clinician.

What to Eat on a Paleo-Friendly Ketogenic Diet

At its most basic, the diet should be made up of ample sources of fat, moderate amounts of protein, and a sprinkling of carbohydrate.

Fat: Makes up the majority of the diet, including nut and seed butters like coconut butter, cacao butter, macadamia nut butter, and sunflower seed butter; animal fats like ghee, schmaltz, tallow, and lard; plant oils like cold-pressed olive oil, coconut oil, and responsibly sourced palm oil; plus olives, coconut milk or cream, and whole nuts and seeds.

Protein: Consumed in moderation, with enough for growth and/or lean body mass maintenance and repair. Include grass-fed or pastured cuts of beef, lamb, or pork; free-range eggs and poultry; sugar-free bacon or other cured products; wild-caught fish and fish eggs; and grass-fed or pastured organ meats. The preferred method of calculating protein needs follows the “one gram per killogram of bodyweight” rule, and this should be adjusted for individual growth or recovery needs. It is important to balance protein with carbohydrate to prevent gluconeogenesis, which depletes the body’s muscle and other tissues when carbs are low .

Carbohydrate: Included in small doses to avoid gluconeogenesis, to add fiber, and to aid in digestion. Include non-starchy vegetables like leafy greens, broccoli, cauliflower, cabbage, garlic, onions, leeks, celery, asparagus, and the like, in addition to low-sugar fruits like berries, citrus, and avocado.

Functional Foods: These items offer benefits that go beyond calorie and macronutrient needs. A holistic ketogenic diet should include bone broth (which is a rich source of collagen, gelatin, and electrolytes) as well as a low-carbohydrate food-based probiotic (like that from coconut water kefir or traditional lacto-fermented condiments like kimchi, pickles, or sauerkraut) and low-carbohydrate sources of soluble and insoluble fiber to nourish intestinal bacteria and promote motility.