Can u lose 5 pounds in only 2 days? My friend said she did but i don't believe her. is it true though?

One of my friends said that she lost 5 pounds from the last 2 days of playing basketball and walkin her dog. she "said" she used to weigh 87 pounds but now she weighs 82. i thought she was lying. BIG TIME. i mean COME ON!! NO ONE CAN EVEN LOSE 1 POUND IN 2 DAYS!! anyways, i just wanted to know if i was right or if my friend was ACTUALLY telling the truth about that. (i thought it was impossible to lose THAT much in only 2 days! isn't it? i'm not really sure right now and that question has been buggin me for WEEKS!!) so PLZZ answer. i'm REALLY curious.