Review Question - QID 213892

A 17-year-old boy is brought to the hospital after fainting while warming up for his high school wrestling match. He admits to restricting his food intake to 300 calories per day recently and drinking little water in order to lose weight. His current weight is 105 lbs (47.7 kg), height is 67 in (170.1 cm), and body mass index (BMI) is 16 kg/m^2. He is admitted for dehydration/malnutrition and given IV thiamine and IV fluids. He is provided with meals and observed to ensure he is eating them. Calorie counts, vital signs, and weight are monitored each day. By day 3, he is eating 2-3 meals per day and exceeding the calorie goals set for him. Which of the following is this patient at greatest risk for at this time?