Ketosis

Ketosis is a metabolic state in which the body shifts from using glucose as its primary fuel source to burning fat and producing molecules called ketone bodies (acetoacetate, beta-hydroxybutyrate, and acetone) for energy. This shift occurs when carbohydrate intake is significantly reduced — typically below 20-50 grams per day — depleting the body's glycogen stores and forcing it to mobilize fatty acids from stored body fat and dietary fat.

Ketosis is a normal physiological response that historically allowed humans to survive periods of food scarcity. When glucose is unavailable, the liver converts fatty acids into ketone bodies, which can cross the blood-brain barrier and fuel the brain, heart, kidneys, and muscles. The brain typically relies on glucose but can adapt to derive up to 75% of its energy from ketones during extended ketosis.

Nutritional ketosis (blood ketone levels of 0.5-3.0 mmol/L) is a controlled, safe metabolic state distinct from diabetic ketoacidosis (DKA), a dangerous condition in type 1 diabetes where ketone levels spike to 10+ mmol/L alongside very high blood glucose. The ketogenic diet deliberately induces nutritional ketosis and has been studied for weight loss, type 2 diabetes management, epilepsy treatment (its original medical use), and neurological conditions.

Ketosis has gained significant attention for potential benefits in weight management, blood sugar control, and neurological health. If you're considering a ketogenic diet, discuss it with your healthcare provider — particularly if you have diabetes, kidney disease, liver disease, or a history of disordered eating.

Research supports the ketogenic diet's efficacy for drug-resistant epilepsy and shows promising results for type 2 diabetes management and short-term weight loss. However, long-term safety data is limited, and the diet's restrictive nature can make it difficult to sustain and may lead to nutritional deficiencies if not carefully planned.