Used to be a manager in a McDonalds for 7 years. Every item is profitable. The drinks are insanely so i believe. I think it was 1 or 2p cost to fill a large soft drink. The restaurant I worked in had continued sales growth every year too. Insane profits considering it was corporation owned and they don't have to put any money in, all the store costs/budget come from itself.

I just want to say though to everyone, treat the staff with a little more respect. It's a hard job and it takes a tole emotionally and mentally on you. The customers are telling you your worthless and you come online for some escapism and you continually see people belittling people who work in that industry.