Well, that's because we can actually store a limited amount of sugar inside our body. So to be more specific, in our fluid, so places like our blood plasma and the fluid found in the cell, so cytoplasm and fluid found in our tissue, in these areas, we can store a maximum of about 20 grams of glucose. Now, in our glycogen stores, we can basically store about 190 grams of usable sugar, sugar that can be readily used and can be readily accessible by those cells. And so together, 20 grams in the body fluid and 190 grams in glycogen, we essentially store about 210 grams of sugar. Now, on a daily basis, an individual that, let's say, is not an athlete needs about 160 grams to actually survive. And 75% of that is actually used by the brain cell.