The BITE is a questionnaire which, as its name suggests, is designed to measure typical psychological and behavioural aspects of bulimia and related problems.
The original paper about the measure is Henderson, M., & Freeman, C. P. L. (1987). A self-rating scale for Bulimia, the ‘BITE’. British Journal of Psychiatry, 150(1), 18–24. https://doi.org/10.1192/bjp.150.1.18. The measure is unusual in having two rather separate scales: a severity scale based on the frequency of behaviours and a symptom scale which is more a mix of behavioural and psychological items.