Background: A growing body of evidence suggest s that higher fat content diet may be more beneficial for ventilator-dependent patients. Therefore, the aim of the present prospective study was to assess whether the highfat low-carbohydrate diet has an advantage role over the usual enteral nutrition (EN) diet. Methods: The study was conducted on 40 patients with repertory failure who were admitted to the critical care unit of Benha University and required mechanical ventilation. Patients were divided into two groups: group A which received the usual high-fat low-carbohydrate diet; and group B which received ready regular EN. The statistical analysis was conducted using SPSS version 21. Results: Twenty patients were included in group A and similar number of patients were included in group B. The mean mechanical ventilation duration in group A was 8.5 ± 4.7 days and in group B 4.4 ± 1.6 days, the difference between both group was statistically significant (p