Here’s the fundamental bit of biology that underpins a lot of what’s on this website. You’re either carb-adapted or keto-adapted. It turns out your body and brain prefers to be in one of two metabolic states. In our society, practically everyone eats a diet that puts them in the carb-adapted state. The conventional wisdom that dominates medicine, nutrition, and human physiology is based on studies of carb-adapted individuals and populations. High sugar diets take that to an unhealthy extreme. There’s another option, keto-adaptation, which dramatically changes the way your brain and body function. There’s a huge need for good science to be done evaluating the keto-adaptated state and to compare and contrast the two states. Unfortunately, most clinicians and researchers don’t even really understand that ketone metabolism exists, let alone want to work with the topic. They commonly confuse it with a pathological condition in sometimes encountered in diabetics called keto-acidosis, very high and dangerous levels of ketones in the blood. In a keto-adapted person, ketones are only slightly elevated since they get used as fuel almost immediately.
Here’s a schematic of a glucose molecule. The angles on the backbone are carbon atoms. Os are oxygen atoms, Hs hydrogen atoms. A carb-adapted person is using glucose molecules for most cellular metabolism, except in muscle cells. Glucose is half of the sucrose molecule (table sugar) or about half of high fructose corn syrup. It’s the sugar that forms the starches in grains and vegetables. Your cells use a mechanism called glycolysis to split glucose into two pyruvate molecules, then feed those into the mitochondria, the little “organelles” inside every cell that produce the vast majority of the Adenosine Tri-phosphate (ATP) energy molecules your cells need to stay alive.
Here’s beta-hydroxybutric acid, a ketone. A keto-adated person is using ketone molecules for most cellular metabolism instead of glucose. Like glucose, the ketones convert easily into molecules that feed right into the same pathways in the mitochondria that glucose-derived pyruvate uses, i.e. the Krebs (Citric Acid) Cycle (See also my Endurance Training page.). Ketones are derived from fats. Unlike fats, but like glucose, they’re water-soluble. This is important, because they can float around in your bloodstream and cellular fluid just like glucose does. Actual fat molecules (triglycerides and cholesterol) mostly have to be transported in “lipoproteins.” Lipoproteins are classified by size and density. The inaccurate science of the 20th Century demonized the “Low Density Lipoproteins,” (LDL) as so-called “bad cholesterol.” It turns out the only bad components are the Small Dense LDL particles produced when you eat sugar, not fat. More on my Cholesterol page.
For the first 1.8 million years, members of our genus, Homo, probably spent most to their time in the keto-adapted state, except in fruit and berry season. Your brain and organ systems work better when they’re in the state that drove natural selection (evolution) for 99.3% of the evolutionary history of our lineage.
Here’s an excellent lecture by Jeff Volek explaining “The Many Facets of Keto-Adaptation.”