IMAP syncs all your email so that you can have it on every device you use. This is a great feature for people on the go that need access to their email messages wherever they are, but it does have some drawbacks. It has to do with space. 200mb may sound like a lot coming from 25mb, but if you have had email for years it may not be as much as you think. When you switch to the new protocol, you may find you run into errors pretty quickly. The trick is only to subscribe to email folders that you need to have access to across all your devices.
The easy way to subscribe, or in our scenario unsubscribe, from folders is to log in to webmail.
Click Folders at the top.

Click the folder you want to unsubscribe to and then unsubscribe.