“Eat donuts and still be in ketosis!”
Is this true? Can you eat all the sugar you like and still get the benefits of a ketogenic diet? Let’s slow this train down for a minute. If something sounds too good to be true, it usually is. But in this case, the oft-used phrase applies: “It’s complicated.”
If you follow health and nutrition news, it’s hard to miss the buzz about ketogenic diets. Ketogenic diets are low-carb diets to the extreme: they’re high in fat, moderate in protein, and very low in carbohydrate (typically under 50 grams of carbs a day, but often even lower, closer to 20-30 grams per day). The ketogenic diet (KD) was originally developed as a medical therapy for epilepsy, when doctors sought to create a diet that could mimic the physiological effects of fasting, yet be sustained for the long term. (It was recognized as far back as Ancient Greece that fasting was effective for epileptic seizures, but alas, people can’t fast indefinitely.) The diet was popularized in the 1920s but fell out of favor not long after, with the advent of anti-epileptic medications. However, despite use of these drugs, epilepsy surgery, and other interventions, many people continue to have uncontrolled seizures, and the KD has proven to be quite effective in this population.
Over the past few decades, the KD has experienced a resurgence and its uses have expanded far beyond epilepsy. Evidence supports the KD being beneficial for fat loss, polycystic ovarian syndrome (PCOS), type 2 diabetes, acid reflux, cardiovascular disease, migraines, and more. The KD is such a dramatic change from how most people eat that it induces multiple important biochemical and hormonal changes in the body. Among them are reductions in blood glucose and insulin levels, reduced inflammation, decreased triglycerides and increased HDL cholesterol.
One of the key things a KD does is “reprogram” metabolism. Think of the human body like a hybrid car: it can run on different types of fuel. In fact, we always run on different types of fuel concurrently, but one predominates, and different tissues have different preferred fuels that they use most efficiently. What the KD does is transition the body away from a primarily carbohydrate/glucose-dependent metabolism to a fat-based metabolism. When there’s very little carbohydrate coming in through the diet, the body must shift to using a different fuel source, and the one it shifts to is fat. (That’s why we carry so much of it around on our hips and bellies! We may not like the way it looks, but it’s there for a reason.)
A byproduct of having a fat-based metabolism is ketones. Think of ketones as the exhaust coming out of an engine: when the body burns fat, it produces ketones. But unlike car exhaust, ketones are a good thing! They’re not a waste product; they are actually a kind of fuel source, themselves. Most cells can use ketones, but skeletal muscle cells (like your biceps and glutes), cardiac muscle cells (in your heart), and neurons in the brain and central nervous system are especially good at using them, which is why ketones might be good for the heart, good for athletic performance, and especially good for cognitive function and banishing brain fog.
With such a wide array of applications for ketones, scientists have developed exogenous ketones—“exogenous” meaning from the outside. These exogenous ketones are available in different forms, most of which come as a powder that you mix with water or another beverage and consume as a drink. Consider exogenous ketones a kind of “ketone supplement.” People who consume exogenous ketones will quickly show elevated levels of ketones in their blood. This is a great thing—in certain circumstances.
There are some conditions—in particular, neurological and neurodegenerative disorders (e.g., Alzheimer’s disease, Parkinson’s disease)—where beneficial effects of ketosis might not occur unless a minimum threshold of ketone level is achieved and sustained. This level would likely differ among individuals, but there’s a good chance this threshold level would not be attainable by diet alone. In these situations, exogenous ketones might be a game changer in terms of adjunct therapy. (Pharmaceutical drugs for these conditions typically aren’t very effective, and the ones that are, come with some pretty gnarly side-effects.)
As mentioned earlier, exogenous ketones might also be beneficial for elite athletes, who are always looking for an edge. Much research remains to be done in this area; so far, it appears that exogenous ketones are more beneficial in endurance athletics than for power sports requiring short bursts of high intensity. Exogenous ketones might also help increase the rate of post-workout glycogen replenishment.
However, here’s where the “too good to be true” part comes in. It’s important to make a distinction between a ketogenic diet and exogenous ketones. Slick and unscrupulous marketing may make exogenous ketones appealing to the public by framing the message to sound like people can reap the full range of benefits of a ketogenic diet simply by supplementing with ketones. If someone takes exogenous ketones, yes, they’ll have elevated levels of ketones in their blood. But as soon as those ketones have been used by the cells, they’re gone. The effects are fleeting. Contrast that with a change in diet that fundamentally alters the body’s fueling system to produce endogenous (internal) ketones 24/7.
Exogenous ketones can be a powerful adjunct to a low carb or ketogenic diet, but they’re not a complete substitute for it. To be clear, these precious molecules can absolutely be a key part of nutritional management for various health concerns, and they’re a boon to individuals with otherwise intractable conditions. If you’re wondering if exogenous ketones might have a role in your life, work with your qualified healthcare professional to see if they’re appropriate for you.