Annoying People

Ok, so a fellow employee and I were discussing the calories in different foods trying to decide what to have for lunch. As I was looking something up on the computer, another fellow employee came up and started talking to the girl I was discussing calories with. I turn around to tell her how many calories were in the item we wanted to eat for lunch. The girl who was talking to her said "You are getting on my nerves with all that calorie crap!" At first I was taken back, but then I responded with "This was a previous conversation before you walked up, and if you don't want to hear it, go back to your desk". I tried to come over as joking, but my friend said I sounded mean. OOOPS! Oh well, I'm not gonna have someone act like I'm doing wrong by finding out how many clories something has before I eat it!