AbstractDespite the implementation of ‘Enhanced Recovery After Surgery’ (ERAS) protocols, major abdominal surgery is still associated with significant and detrimental losses of muscle mass and function in the post-operative period. Although ERAS protocols advocate both early mobility and dietary intake, dietary composition in the immediate post-operative period is poorly characterised, despite muscle losses being greatest in this period. Herein, we show in 15 patients (66 ± 6 y, 12:3 M:F) who lost ~10% m. vastus lateralis muscle mass in the 5 days after open colorectal resective surgery, mean energy intake was only ~25% of the minimum ESPEN recommendation of 25 kcal/kg/d and daily dietary protein intake was only ~12% of the ESPEN recommended guidelines of 1.5 g/kg/d. Given the known importance of nutrition for muscle mass maintenance, innovative dietary interventions are needed in the immediate post-operative period, accounting for specific patient dietary preference to maximise compliance (e.g., soft-textured foods).