this. almost like the poster doesnt have a clue about the nonsense spouted. ingesting gluten or sugar, like bread and fruit we've been eating for a couple of millenia, suddenly is deadly to humans.
the detail i dont know but seems to me that the process that stores fat would be reversed to take back the fat - LIFO. for FIFO you'd need a second mechanism at the other end of the deposits of fat to take the older deposits away.
they say that all your cells regenerate and are replaced over time, some faster than others, so that after 7-8 years you are completely renewed. like Trigger's Broom. however i suspect that may be bobbins.
i'd hazard a guess its LIFO from general metabolism as the newer fat is more...