30.11.2018
@Robert
Habe mich jetzt doch noch mal um konkretere Zahlen bemüht (angemerkt: zu deinen konkreten Verhältnissen wird man nichts finden, lediglich Zahlen, die in einen ähnlichen Kontext passen):
Despite the relative predominance of circulating β-hydroxybutyrate, the splanchnic productions of both β-hydroxybutyrate and acetoacetate were approximately equal, totaling 115 g/24 h. This rate of hepatic ketogenesis was as great as that noted previously after 5-6 wk of starvation. Since the degree of hyperketonemia was about threefold greater after 5-6 wk of starvation, it seems likely that the rate of ketone-body removal by peripheral tissues is as important in the development of the increased ketone-body concentrations observed after prolonged starvation as increased hepatic ketone-body production rate.
Splanchnic glucose release in this study was 123 g/24 h, which was less than that noted previously after an overnight fast, but was considerably more than that noted during prolonged starvation. Hepatic gluconeogenesis was estimated to be 99 g/24 h, calculated as the sum of lactate, pyruvate, glycerol, and amino acid uptake. This was greater than that observed either after an overnight fast or after prolonged starvation. In addition, a direct relationship between the processes of hepatic ketogenesis and gluconeogenesis was observed.
(https://www.ncbi.nlm.nih.gov/pmc/articles/PMC301639/)
Da man langfristiges Fasten nicht mit proteinsparendem, isokalorischen No Carb vergleichen kann, sind die hier angeführten Zahlen ganz bestimmt nicht so weit weg von dem, was du machst.
Wichtig:
Not all amino acid carbon will yield glucose; on average, 1.6 g of amino acids is required to synthesize 1 g of glucose [4]. Thus, to keep the brain supplied with glucose at rate of 110 to 120 g/day, the breakdown of 160 to 200 g of protein (close to 1 kg of muscle tissue) would be required.
This is clearly undesirable, and the body limits glucose utilization to reduce the need for gluconeogenesis and so spare muscle tissue. In comparison with glucose, the ketone bodies are a very good respiratory fuel. Whereas 100 g of glucose generates 8.7 kg of ATP, 100 g of 3-hydroxybutyrate can yield 10.5 kg of ATP, and 100 g of acetoacetate 9.4 kg of ATP [5].
The brain will use ketone bodies whenever provided with them (i.e., whenever blood ketone body levels rise). (...)
However, continued use of some glucose appears obligatory [6] and is supplied by way of hepatic gluconeogenesis. Finally, because of the inactivation of pyruvate dehydrogenase (by the low insulin concentration), the glucose that is used by tissues outside the brain is largely only partially broken down to pyruvate and lactate, which can then be recycled in the liver trough gluconeogensis [7]. Therefore, red blood cells, for instance, which have an obligatory requirement for glucose, are not depleting the body of glucose.
(https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2129159/)
Fasst man beide Studien zusammen: Es gibt definitiv Engpässe (vor allem mit Blick auf die Gluconeogenese). Die Frage ist, wie gut der Körper darin wird, Nährstoffe zu recyclen oder den Verbrauch von limitierenden Substraten zu drosseln.
