How Cells Lose Energy
When the body runs mainly on glucose, a protective mechanism activates in cells. If a cell received all its energy from 100 mitochondria at once on glucose alone, it would simply "explode from energy overload." For this reason, the cell is forced to reduce the number of these "batteries" — mitochondria.
When a normal person eats mainly glucose as the primary fuel source, the number of these energy batteries in the cell—mitochondria—decreases, because if you took 100 mitochondria and the cell ran on glucose, it would simply blow up from the energy excess.