Background and Objectives: The optimal energy intake for early nutrition therapy in critically ill patients is unknown, especially in Chinese patients with a lower BMI. This study investigated the relationship between energy intake and clinical outcomes in this patient population. Methods and Study Design: A retrospective study was carried out at a tertiary hospital. Critically ill patients were recruited and divided into 3 tertiles according to the ratio of actual/target energy intake during the first week of hospitalization in the intensive care unit (ICU) (tertile I, ＜33.4%; tertile II, 33.4%-66.7%; and tertile III, ＞66.7%). 60-day mortality and other clinical outcomes were compared. To adjust for potentially confounding factors, multivariate and sensitivity analyses were performed exclusively in patients who stayed in the ICU for ≥7 days. Results: A total of 325 patients with a mean BMI of 22.5±4.7 kg/m^2 were recruited. 60-day mortality was similar between the 3 tertiles. In the unadjusted analysis, tertile III had a longer length of stay in the ICU and at the hospital, longer duration of mechanical ventilation, and higher rate of ICU-associated infections, but only the latter showed a significant difference between the 3 tertiles in the multivariate and sensitivity analyses. Logistic regression analysis showed that energy groups was an independent risk factor for ICU-associated infections. Conclusions: Energy intake in early nutrition therapy influences risk of ICU-associated infections in Chinese critically ill patients with lower BMI. Furthermore, patients with near-target energy intake have more frequent ICU-associated infections.