Definitely a symptom of depression...and it can go the other way too...overeating...
When I am feeling physically ill...food is not on my priority...Mom said she always knew when I was getting better, cause I would get hungry. Same with emotional and mental stuff..no hungry, don't care about self hygiene, daily routines stop, time loss..etc. Luckily, when conscious of the path I'm on..I will force myself to do those things...even when it doesn't seem to matter...and on that path, I do find it does matter...fight back!