Excel File Size in Question

Ok heres the thing I know it happens to alot of people and its been accuring alot as of late. Excel file will reach 1.5megs with little text in it form a file that starts at 42KB. It only happens on rare things. For example I might make something with 4 pages of text and still wont get that big then someone else dose something as simple as 3 lines and it grows rather large. Is there any reason for this the Office suites are setup the same no differance other then user accounts.