Acute and chronic respiratory insufficiency, including conditions like acute respiratory distress syndrome (ARDS) and exacerbations of chronic obstructive pulmonary disease (COPD), are major causes of morbidity and mortality in intensive care units (ICUs). These conditions often require comprehensive respiratory and nutritional support. ARDS, caused by factors like severe pneumonia or sepsis, leads to severe hypoxemia and metabolic impairment. Nutritional management of ARDS includes early enteral nutrition and, if needed, parenteral nutrition, with specific focus on macronutrient composition. COPD, a disease commonly linked to smoking, leads to malnutrition and cachexia, worsening patient’s prognosis. In exacerbated COPD, early nutritional assessment is crucial to address malnutrition and muscle wasting. Both conditions underline the importance of tailored nutritional care to improve outcomes for critically ill patients in the ICU.