Just thought it's interesting how, in contradiction with what one can learn from RP, it is sometimes written in more mainstream media that brain uses lactic acid as preferred source of energy, and are quoted studies such as
http://www.ncbi.nlm.nih.gov/pubmed/21593331
http://www.ncbi.nlm.nih.gov/pubmed/21593331
Furthermore, a neuroprotective effect of lactate during hypoglycemia or cerebral ischemia has been reported. The majority of the current evidence concerning lactate metabolism at the cellular level is based on in vitro data; only a few recent in vivo results have demonstrated that the brain preferentially utilizes lactate over glucose