Q: Too much email is being downloaded automatically.  Where is the setting to limit this?

It depends on your mail account.  If the options is avialble you will find it in Settings > Mail, Contacts, Calendars > Tap on your Mail Account > Mail Days to Sync

That Mail switch just means Mail is turned on.  This example account is an Exchange account where I could choose to not use mail from it (turn off that mail switch) and use it to sync like my contacts or something or multiple options.  If I turn off that Mail switch, then all of my emails disappear until I turn it back on.

Your mail itself is not backed up to iCloud, only the account info (minus the password).  When you restore form an iCloud backup, it restores your account, then asks for your password, then imports your mail from the account itself, not iCloud.

Source: http://support.apple.com/kb/PH12519

Here’s what iCloud backs up:

• Purchased history for music, movies, TV shows, apps, and booksYour iCloud backup includes information about the content you have purchased, but not the purchased content itself. When you restore from an iCloud backup, your purchased content is automatically downloaded from the iTunes Store, App Store, or iBooks Store. Automatic downloading is based on iTunes in the Cloud availability by country, and previous purchases may be unavailable if they have been refunded or are no longer available in the store.
• Photos and videos in your Camera Roll
• Device settings
• App data
• Home screen and app organization
• iMessage, text (SMS), and MMS messages
• Ringtones
• Visual Voicemail

Your iOS device backup only includes data and settings stored on your device. It doesn't include data already stored in iCloud, for example contacts, calendars, bookmarks, mail messages (from iCloud.com email accounts, i.e. mac.com, me.com, or icloud.com), notes, shared photo streams, My Photo Stream, and documents you save in iCloud using iOS apps and Mac apps.

Paparotzi2011 wrote:

 

Just thought of a follow up question....I am not backing up my mail in iCloud (I am backing up everything else.)  Do you think that is why I'm not offered that Mail Days to Sync option?  I noticed in your response that you had the mail backup turned on.  Thanks.

Only Exchange has that option on iPhone.

Most accounts are either POP or IMAP accounts.

IMAP accounts sync information back and forth from the email server to the device.  Example: If my yahoo.com account (which is IMAP) is set up on my iPhone, iPad, and Computer when I delete an email form my iPhone, it also deletes from yahoo.com and subsequently my iPad and my computer.

POP accounts are very old account type but they are still in use.  These accounts are usually found provided by your internet service provider like yourname@yourISP.com  POP accounts do not sync.  When you add a POP account to your iPhone, the iPhone goes into the account and grabs a copy of every single email sitting in your account at yourISP.com  This can also occur after an update.  You may have went in and sdeleted emails and all, but as soon as you update, they all come back because with POP accounts, when you delete form your iPhone, it only deletes from your iPhone, not from yourISP.com  This is a limit by the email service provider and not your iPhone.

My guess is that your account is a POP account.  What you can do is go into your email on the internet, like via Safari or via the web browser on your computer.  Clean up your emails, deleting what you don't want.  Then go back to your iPhone and delete and re-add your email account in Settings > Mail, Contacts, Calendars.  This will make your iPhone delete what it currently has for your emails, then when you re-add the account, it will go to your email and grab a copy of what you currently have online.

My wife had this problem with her hotmail.com account.  She updated and had 32,000 unread messages!

You're welcome. Glad I could help!