Twoconditions seem common to those studies showing that theketogenic diet can induce sustained ketosis in rats: either ahigh intake of medium chain TG (fatty acids of 8-10carbons) is necessary or long-term underfeeding (oranorexia) resulting in negative energy balance and lowweight gain. Sensitivity to anorexia is higher in weanlingrats (21-22 days old) than later on, so to avert theconfounding effects of impaired weight gain, we waited tostart the ketogenic diet until the rats were 50 to 52 days old.These parameters affecting the magnitude and duration ofketosis have not been studied in detail so their thresholds tomaintain (or prevent) prolonged ketosis are presentlystill unknown.