With the launch of new version of iOS 7, Apple has made it easier to update all of your apps. Previously, you have to go through individual updates for all apps, making it time consuming. Now, in iOS 7, you can select the option of auto-updating all apps in background.
If you don’t want to update your apps automagically, go to Settings >> iTunes & App Stores >> Automatic Downloads section >> Updates
Updates toggle button is set to on by default. To switch your auto downloads off, Tap it and your apps will not download by themselves.