Personally, I don’t like Facebook changed its new feed to a smaller font size, I believe that many of you have complained about this. May be Facebook has their own reason to change the new feed font size, but I really can’t accept it because it is really hurt my eyes.
If you want to make font size bigger, you actually can do it. On your web browser, press CTRL and + (or, CMD and + on Mac) on your keyboard to increase the font size and press CTRL and – (CMD and -, for Mac) to decrease font size. This is only way you can do with changing the font size on web browser.
I hope Facebook can change back the font size like before, and I can’t find any reason why bigger font size looks bad.