Esther would like to gain weight, but despite eating regular meals and having no disordered eating practice or eating disorder, her bmi dropped from 19.0 to 16.2 in one year. according to this information, esther's physician will need to

Drop in BMI (Body Mass Index) even after eating healthy and having no eating disorders may be a result of any chronic disease or any chronic disorder.
According to the information provided in the question above, Esther's physician will need to KNOW WHETHER ESTHER IS SUFFERING FROM ANY CHRONIC DISEASE OR NOT.

Digestion because it removes waste