Outlook on Mac is continually uploading to the Internet. How can I stop this?

My wife runs Outlook on her Mac. Every time we start it up, or it is running, it is continually uploading to the Internet and totally ties it up. I don't think that it is uploading emails, as she is not that busy. I scanned the app file for viruses and found nothing. We are in the Bay Area, and Avast shows that Outlook is connecting to Miami, or other weird places, like Germany. I am thinking that it is running as a bot. If not, how can I get it to stop uploading? I am not sure which version she is running, but I just checked for updates and it came back saying this is the most recent version.

At a different Microsoft forum, a response said that Outlook constantly syncs with the web. If this is the problem, how can I turn it off or moderate it? The fact that it grabs nearly all of the web bandwidth (we get 44MB on our Internet), continually, just seems crazy to me. Help please.