Keep a deficit and you will lose weight (if that’s what you’re going for). When I ate that little amount I would get light headed and lack energy and focus (but that’s me).
Eat a salad or chicken breast and call it a night. Start again tomorrow. That’s what I would do.
You don’t technically need to ingest any calories at all, as long as you’re metabolically flexible and have sufficient fat stores to burn. The fat will provide all the calories you need. Of course, if you’re not metabolically flexible, your body will likely not be able to burn fat fast enough, and if you don’t eat, you’ll likely feel exhausted, weak, irritable, light-headed, dizzy, or even faint.
The good news is that all you need to become metabolically flexible is time and discipline. Just keep slowly extending your fasting window and eventually your body will optimize the processes and pathways used for burning fat, and will be able to supply all the energy you need.