File size increased five times

Hello,

I made some apparently minor changes to my model by adding two new tables (each with 2 columns and 4 rows), and then referencing them in the main table by adding two calculated columns (basically assigning values 1 through 4 based on category). There is a one to many relationship between these two newly created tables and the main table.

This change alone made my file size increase from 10MB to 57MB and I am not sure why. I read somewhere that disabling "Auto Date/Time" helps reduce the file size and once I did that it reduced it to 4MB however one of the measures had an error since it relied on the date hierarchy created by Power BI automatically.

Any other ideas what I could do to reduce the file size to be close to the original file size of 10MB? Is it possible that just adding two small tables and adding two calculated columns in the main table can increase file size 5 times?

Thank you!