I would think that grilling hamburgers will be better than frying in butter any time. However, I don't think there is such a significant change in the amount of calories consumed.
If I were you, I'd simply record it with the fat percentage it says on the pack, grill it instead of frying it and comfortably know that you've saved a few extra calories.
"Losing weight is never about eating as little as possible"
"Eating enough, moving more, not eating stupid s**t = losing weight."
"Do. Or do not. There is no trying."
- Master Yoda.
I started my weight loss journey on October 4th, 2010 - and this is what I have accomplished so far: