A 21-yeаr-оld femаle client presents tо the emergency depаrtment with "stоmach issues." She denies frequent vomiting, but states that she has frequent diarrhea that has recently included blood. Labs reveal: potassium of 2.9 mEq/L, and metabolic alkalosis. She later tells a nurse that she frequently uses laxative due to a "slow digestive system". The patient's BMI is 20.2 kg/m². Which eating disorder does the PMHNP suspect most based on these assessment findings?