The American Society for Parenteral and Enteral Nutrition recommends hypocaloric feeding for critically ill patients with a BMI of >=30.0 kg/m2. However, the cut-off value of obesity in Japan is BMI >25.0 kg/m2, due to the higher prevalence of type 2 diabetes mellitus, and cardiovascular risk factors, even at a lower BMI than in Western populations. Thus, the optimal energy intake for critically ill, overweight Asian patients is unknown. A retrospective chart review was conducted in patients with BMI of >=25.0 kg/m2 in an emergency intensive care unit (EICU). Patients were categorized into two groups by average daily energy intake during the first week in the EICU, with Group A at <50% of requirement and Group B at >=50%. A total of 72 patients with a median BMI of 27.5 kg/m2 were included in the study. No significant differences between the groups were observed for all-cause mortality, ICU-free days, or length of hospital stay. The number of ventilator-free days (VFDs) was significantly higher in Group A than Group B (20.0 [15.5-24.5] vs 17.0 [2.0-21.0] days; p=0.042). On multiple adjusted analysis, however, we found that %energy intake/requirement was not independently associated with VFDs (regression coefficient=0.019; 95% confidence interval, -0.115-0.076). Energy intake in the first week in the EICU did not influence clinical outcomes in critically ill, overweight Japanese patients. Confirmation of these results in larger, randomized trials is required.