Adele's treat: "in and out"
Solution 1:
IN N OUT is a hamburger restaurant chain in the western United States. Perhaps she avoids unhealthy hamburgers as a rule to keep up her appearance, but has decided to indulge to cheer herself up or celebrate?
An ABC news article states:
Despite her on-stage troubles, the singer, 27, still had a pretty great night. Because of the snafu, she wrote, she treated herself to a late-night snack at an L.A. standby: In-N-Out Burger
That makes it very clear.