Non-inferiority of Continuing Oral Intake Versus Fasting in Patients With Acute Respiratory Failure

Inclusion Criteria: * Male or female ≥ 18 years old * Participant affiliated to a social security scheme * Express oral consent of the participant, or failing that of the trusted support person, or failing that of the next of kin * Patient hospitalised in an intensive care unit or in a continuous surveillance unit or in an intensive care unit for less than 24 hours. * Criteria for acute hypoxaemic respiratory failure defined as. * Respiratory rate \> 25 cpm or indifferent if SARS-CoV-2 (Severe acute respiratory syndrome coronavirus 2) infection occurred ≥ 1 time since admission. * PaO2/FiO2 \< 200 mmHg or equivalent SpO2 (oxygen saturation)/FiO2 (fraction of inspired oxygen) i.e. \< 235 (measured under at least 10 L/min high concentration mask) Exclusion Criteria: * Patient with criteria for immediate intubation: * Persistent or worsening respiratory failure (respiratory rate \> 40/min, respiratory failure on physical examination, respiratory acidosis with pH (hydrogen potential ) \< 7.25, copious tracheal secretions, hypoxia with SpO2 \< 90% despite FiO2 \> 80% for more than 5 minutes without technical dysfunction). * Major haemodynamic failure (need for increasing vasopressor support with instability and hypoperfusion). * Neurological failure (Glasgow score \< 8). * Cardiac or respiratory arrest * Chronic lung disease: chronic obstructive pulmonary disease (GOLD grade 3 or 4: Global Initiative for Chronic Obstructive Lung Disease) or other chronic lung disease requiring long-term oxygen or ventilation (this does not include a patient undergoing continuous positive nocturnal pressure for sleep apnoea syndrome). * Contraindications to oral nutrition: known previous swallowing problems or inability to swallow, digestive sutures, admission for inhalation pneumonia, exclusive parenteral nutrition, etc. * Patients with a nasogastric or orogastric tube, a jejunostomy or a feeding ileostomy * Patient already on invasive mechanical ventilation on admission * Limitation of therapies including a decision not to intubate * Incapacitated adult (guardianship or curators) * Pregnant, parturient or breast-feeding women * Tracheostomised patient * Patient already included for the first time in this study