i dont claim to be an expert on the subject, and I am only a wannabe (booooo), but an airline will look at physical appearance the same as any other employer.
Firstly, being in relative good shape apparently is the sign of a disciplined individual, and shows the ability to structure and plan their time better. Also, the concept of only being able to make one first impression couldn't be truer; research in the field of human resource proves that only about 7% of what comes out of your mouth will actually count, and that a ridiculous figure (circa 70%) is on how you look and body language. Ill be laying off the cream cakes then