Galaxy S3-Google Calendar consuming lots of gprs data

Hello,
I have a Samsung Galaxy S3 handset. I recently activated my phone’s internet connection and went for a simple data plan. I don’t use internet a lot in my phone. But I recently came across a fact that I am losing 50 MB data each day from my plan. So it seems some app is causing the problem. So I used a few apps to discover the problem. It was Google Calendar. How can I fix this and stop making the app use up my data plan?
Can anyone tell me the correct way out?

Hello,
It is so easy to do, just put off your internet whenever you are not using the Google Calander app.
This will definitely decrease your consumption of internet data.