[Breath acetone and ketonemia in normal- and overweight subjects during total fasting (author's transl)]

In subjects of ideal weight (7 males and 7 females) total whole blood ketones and breath acetone were determined during a 6 day fast, and in obese subjects (8 males, 18 females) during 6-28 days of fasting. Development of starvation ketosis was significantly slower in overweight than in normal weight subjects. Breath acetone concentration was up to blood ketone levels of 4 mMol/1 a linear function of the blood ketone concentration, beyond that level, however, an additional exponential component became apparent. The highest acetone elimination found was 4.46 mg/min, corresponding to 6.4 g acetone and 11.2 g acetoacetic acid in 24 hours. Hence the decarboxylation of acetoacetic acid to acetone may be an additional mechanism for the lowering of ketoacidosis in starvation.