This was the worry for most of the Samsung users, as there is no way out. It's impossible to change font size and style officially. So how it's done?
Simply go to play store, download a launcher. The best launcher i tried so far is, Nova launche. This let you customise everything. Now you can change the size and style of the fonts, along with the screen and icons. This launcher will not drain battery more than the touchwiz ui does.
