Ketones: the what and why of this fat-burning chemcal
Keystone was a cheap and generally tasteless beer I often drank in the early 90s. It contained no health benefits whatsoever. Fortunately, ketones are another story.
Ketones are chemicals produced by the liver. When your body doesn’t have enough stored glucose (sugar) it begins to break down fat as an energy source. Ketones are the output of this breakdown, which are then used by the body for fuel. When ketones reach a high enough level in the blood we are in a state of ketosis.
Experts don’t agree on optimal ketosis blood levels. Conservative estimates suggest between 1.0mmol/L and 3.0mmol/L.”
So how do we facilitate endogenous (natural) ketone production?
Diet
Consuming 50 grams or less of carbohydrates a day will shift you into ketosis in 3-4 days. This is known as the ketogenic diet, or eating “keto.” In the first week of ketosis, people may experience flu-like symptoms, often referred to as the “keto flu.”
Nutrition wars rage online about whether being in ketosis over the longer term (becoming “fat adapted”) is a healthy thing or not. We’re not wading into that argument here.
Intermittent fasting
Intermittent fasting—varying the length of time between meals—is an effective strategy. An overnight fast puts us close to the ketosis level threshold and ketones increase with longer fasts.
Exercise
Cardiovascular exercise—especially lengthy workouts (2+ hours)—will deplete glucose levels to the point that ketone production begins. Research shows exercising while fasted further accelerates ketone production.
Intermittent ketosis seems inarguably beneficial; you’re burning more fat, after all. Whether long-term ketosis is the best health strategy over the long haul remains up for debate, and you’ll find passionate enthusiasts on both sides.
One note: in diabetics, ketones can be a sign the body is not producing enough insulin to convert glucose (sugar) into energy.
As always, this Sprint Essay is nothing more than an introduction to the concept. Research and consult a medical professional before you start down any new exercise or nutritional path.