(This is not medical advice and I am not a doctor) I don't think ketamine is directly indicated overeating, and I know esketamine isn't for insomnia or overeating. That said, There do seem to be a handful of papers studying the use of ketamine in things that affect sleep, like circadian rhythm [0][1]. In general, ketamine causes sedation in about 70% of those treated with it. Though that is short acting (hours) it may help set an individual for a good sleep, and to the extent that insomnia or overeating are caused by or co-occurrent with depression, ketamine could likely help.

[0] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5866161/ [1] https://onlinelibrary.wiley.com/doi/full/10.1002/brb3.1423