Introduction: The Nutrition Risk in Critically ill (NUTRIC) score is a specific tool for assessing the nutritional risk in the Intensive Care Unit (ICU). Under these conditions, it is extremely important to monitor Enteral Nutrition Therapy and identify main barriers in the control of energy-protein deficit. Objective: To identify main barriers to control the energy-protein deficit in critically ill patients at nutritional risk, on enteral nutrition (EN) and on mechanical ventilation (MV). Methods: Prospective, observational, descriptive study was conducted in an ICU in 2015. Patients >19 years of age on MV and underwent EN for >72 hours. The data collected were NUTRIC score, Subjective Global Assessment (SGA), Cachexia Syndrome, APACHE II, SOFA, ICU time, MV and EN times and main barriers for pausing EN. The protein-calorie deficit was compiled into total days of EN. Results: Total of 62 patients, 22 were excluded, 40 analyzed. The scores were NUTRIC 7 (+0.7), APACHE 26 (+5.2), SOFA 11.5 (+2.2), Body Mass Index 23.2 (+6.2) kg/m², 47% malnourished (SGA B+C), 70% cachexia syndrome and mortality rate of 52.5%. Among these patients, 77.5% underwent early EN and percentage of volume prescribed infused was 89%. It was observed total deficit of -296 (+339) calories and -28 (IQ -58:-2.95) g/protein. Main barriers for pausing EN were extubation 38%, hemodynamic instability 29%, tracheostomy, diarrhea and vomiting, both 6.5%. There was a statistically significant difference between calorie (p<0.003) and protein (p<0.002) deficits in the subgroups of adult patients compared to malnourished elderly patients with cachexia syndrome: -358.9 (+305) calories and -33 (+14.24) g/protein; -91.6 (+190) calories and -18.8 (+7.96) g/protein, respectively. Conclusion: The main barriers in control of energy-protein deficit in critical oncologic patient at nutritional risk on EN and on MV were extubation and hemodynamic instability.