Take a long look at your diet and what you eat on the plane. A lot of crew eat heaps of corbohydrates and are supplied carbohydrate loaded meals to keep energy levels up. If you don't have a high metobolism or excercise daily the excess carbo's store directly as fat. It's a double edged sword, you get tired because of the pressure and don't have enough energy to excercise but then if you don't excercise, you put on weight. I have come to this conclussion due to the fact of seeing alot of new girls come on line that have'nt flown before and put on 2-3 kilo's in the first 2-3 months of being on line. Also don't snack eat healthy, don't go back for seconds and watch your sugar intake.
Long winded I know . But I hope it helps