Indicate the patient's full name with the lowest body mass index in kg/m2.
full name refers to first, last; the lowest body mass index in kg/m2 refers to DESCRIPTION = Body Mass Index from observations where MIN(VALUE) and UNITS = 'kg/m2';
SELECT T1.first, T1.last FROM patients AS T1 INNER JOIN observations AS T2 ON T1.patient = T2.PATIENT WHERE T2.DESCRIPTION = 'Body Mass Index' AND T2.UNITS = 'kg/m2' ORDER BY T2.VALUE LIMIT 1