2.1kg in 5 days is insane.
Word of caution mafoo, spikes of weight loss always get compensated by spikes of weight gain. between 1 and 2 kg's A WEEK is a good target.
Then again, I have no idea the conditions in which you weighed yourself both times, so it might be normal (like if you originally weighed right after a meal).
Good job anyway, hope you have continue and sustained weight loss (obviously to the point of "healthy" and not beyond that).







