Ketosis (aka: “nutritional ketosis”) is a completely natural physiological adaptation that is integrated into the body’s energy strategy whenever carbohydrates are limited, and fat becomes its primary fuel. When this occurs, the liver forms ketones – more specifically acetoacetate (AcAc) and hydroxybutyrate (BOHB) – which enable fatty acids from adipose tissue to be used for energy. Interestingly, beyond safe and effective weight loss, research also suggests that the ketone BOHB may play an epigenetic role in reducing oxidative stress and inflammation (31).
Ketoacidosis is characterized by dangerously high levels of ketones (>10 mmol/L), a roughly 10-fold increase from ketone levels achieved by nutrition ketosis. Ketoacidosis is rare and typically only occurs in people with uncontrolled type 1 diabetes.
Atkins 20 and Atkins 40 are examples of ketogenic diets, which raise ketone levels to 0.5-3 mmol/L—this range is often described as nutritional ketosis when excess ketones are excreted in the urine, breath, and skin (32).