When there isn't enough glucose available, the body needs an alternative strategy to meet the energy demands and to keep the body working properly. (8fit.com)
My ignorant assumption is that 1 very high carb day would provide enough glucose for 1 - 2 low - carb days (assuming training is not too intense). (perfecthealthdiet.com)
The liver can constantly supply just enough glucose in the blood to keep the brain going. (wellnessmama.com)