Metabolic Pathways while fasted and Ketosis

Was just commenting on Patri Friedman’s livejournal (here) regarding how the metabolic channels used while fasting were the same as those used while on a low-carb diet. Taubes notes fact in passing in Good Calories, Bad Calories but since that’s a hard reference to check on the ‘net, here’s another bit of support from Dr. Mike Eades of Protein Power:

If you read any medical school biochemistry textbook, you’ll find a section devoted to what happens metabolically during starvation. If you read these sections with a knowing eye, you’ll realize that everything discussed as happening during starvation happens during carbohydrate restriction as well. There have been a few papers published recently showing the same thing: the metabolism of carb restriction = the metabolism of starvation. I would maintain, however, based on my study of the Paleolithic diet that starvation and carb restriction are simply the polar ends of a continuum, and that carb restriction was the norm for most of our existence as upright walking beings on this planet, making the metabolism of what biochemistry textbook authors call starvation the ‘normal’ metabolism.

As noted before, this makes intuitive sense. While in a fasted state, the body gets its energy fix by robbing the protein for gluconeogenesis from lean tissue and the fat for energy from adipose tissue. While doing low-carb, the body does the same thing — the only difference is that it gets the fat and protein from dietary sources.

The rest of the Eades article discusses ketones/ketosis, which I’m still working on fully understanding (the basics, anyway). Apparently there are other benefits to occasionally being in a ketogenic state that may include “de-junking” our cells. Neat!