Do you do some night time eating? I think we all at one time or another have done this. It is not uncommon. Night time eating also called Night eating syndrome ( NES) has been studied and is more common among bipolar disorder than the general population. There is a classic definition for NES. It is when the consumption of at least 25% of the days caloric intake is done after the evening meal and at least two nocturnal awakenings per night.
We need to study this in depth. We do know that bipolar disorder patients have an increased risk of metabolic syndrome ( also called Insulin resistance or pre diabetes) already due to their psychiatric medications. These individuals have poor sleep and more severe anxiety issues
More studies need to be done