Am I eligible for filing for per diem?

I am in a travelling position and I work away from home for three nights a week.  I am over 50 miles away as well. My employer does pay for my hotel stays, vehicle and gas. But unfortunately I do not get a meal expense. Am I eligible to file for per diem for my meals? That being said to keep hundreds of receipts for meals would be quite tough. Am I able to claim the 48 dollar standard rate? I can prove that I've been out of town because of my hotel receipts I submit to my employer.