For comparison
Using the old =RAND(1,5) text insertion trick; I got 1 paragraph, 98 words, 7 lines and 581 characters with spaces. The .txt file was 581 bytes, the .docx was 12.8 KB and the .doc was 22 KB. (This is just to illustrate the point about the different file formats - I'm not crazy or anything...)
Are you sure you're not using .doc???