Objective To evaluate the clinical efficacy of hypocaloric enteral nutrition in patients with acute severe traumatic brain injury (TBI).Methods A total of 100 patients with severe TBI [Glasgow Coma Scale (GCS) 3-8 points] were enrolled and randomly divided into hypocaloric enteral nutrition group (hypocaloric group, 41.86-62.79 kJ · kg-1 · d-1) and traditional caloric enteral nutrition group (traditional caloric group, 104.65-125.58 kJ · kg-1 · d-1) ,50 patients per group.The enteral nutrition was given at 24-72 hours postoperatively.The changes of total serum protein (TP), serum-albumin (ALB), plasma hemoglobin (Hb), fasting blood glucose (Glu) and major gastrointestinal tract complications were observed and compared at 7 and 14 days after enteral nutrition support.Results Levels of TP, ALB and Hb were lowered in both groups at 7 and 14 days after nutritional support but showed no statistical difference (P ＞ 0.05).Glu was (6.37 ± 1.02) mmol/L in hypocaloric calorie group, significantly lower than (7.35 ± 1.70) mmol/L in traditional caloric group at day 7 after nutritional support (P ＜ 0.05).At 7 and 14 days after nutrition support, nausea, regurgitation, vomiting and complication incidence showed no significant difference between hypocaloric calorie group and traditional caloric group after nutritional support (P ＞ 0.05), but abdominal distension, diarrhea and stomach retention rate in hypocaloric group were significantly lower than those in traditional caloric group (P ＜ 0.05).Conclusion Hypocaloric enteral nutrition can significantly reduce the stress hyperglycemia, abdominal distention, diarrhea, gastric retention and other gastrointestinal symptoms in patients with acute severe TBI.