Water softener with a 2 inch main line

I am looking to install a water softener for my home. The main line into the home is 2 inch which branches off to 1 inch eventually for hot and cold water and then to the fixtures. My question is, if I get a 1 inch water softener installed at the main line, how much pressure loss am i going to see? The softened water would now go back into a 2 inch pipe which will again get distributed to 1 inch pipes.