The nurse managing eating disorders implements medical stabilization protocols, prevents and manages refeeding syndrome, monitors complex physiological derangements, and coordinates multidisciplinary care. Refeeding syndrome pathophysiology: during starvation, the body shifts from carbohydrate to fat and protein metabolism; intracellular stores of phosphate, potassium, and magnesium are depleted despite initially normal serum levels (serum levels reflect only 1% of total body stores). When carbohydrates are reintroduced, insulin is secreted, driving glucose and electrolytes (especially phosphate) intracellularly. The sudden intracellular phosphate shift causes serum hypophosphatemia. Phosphate is essential for ATP production, 2,3-DPG (oxygen delivery), and cell membrane integrity. Severe hypophosphatemia causes: cardiac failure (ATP depletion in myocardium), respiratory failure (diaphragm weakness), rhabdomyolysis, hemolytic anemia (RBC membrane fragility), seizures, and death. The NICE guidelines for refeeding risk include: BMI below 16, weight loss greater than 15% in 3-6 months, little or no intake for 10+ days, and low baseline phosphate/potassium/magnesium. Prevention requires: starting at 10-20 kcal/kg/day (not 1000-1200 kcal), prophylactic phosphate and thiamine supplementation, daily electrolyte monitoring, and gradual caloric advancement over 7-10 days.