Background: Nutrition studies in patients admitted to hospital frequently disregard oral intake because measurement is time-intensive and logistically challenging. In free-living populations, weighed food records (WFR) are the gold-standard and are conducted on weekend and weekdays to capture variations in intake, although this may not translate during hospitalisation. The present study aimed to determine whether oral intake differs between weekends and weekdays in hospitalised patients. Methods: For adult patients initially admitted to the intensive therapy unit with a moderate-severe head injury over a 12-month period, WFR were conducted each week on Tuesday, Thursday and Saturday throughout hospitalisation. Meal components were weighed before and after consumption, and energy and protein intakes were calculated using specialised software. Data are reported as the mean (SD). Differences were assessed using paired t-tests and agreement using Bland–Altman plots. Results: Thirty-two patients had WFR collected on 220 days, 68% (n = 149) on weekdays and 32% (n = 71) on weekends. Overall, daily intakes were 5.72 (3.67) MJ [1367 (877) kcal] and 62 (40) g protein. There were no differences in intake across all days (P = 0.937 energy, P = 0.797 protein), nor between weekdays and weekends, in weeks 1–3 of oral intake (all P > 0.1). Limits of agreement between mean intakes across days were wide for energy [range 11.20 to 9.55 MJ ( 2680 to 2283 kcal)] and protein (range 125 to 110 g). Conclusions: Grouped energy and protein intakes from WFR in hospitalised patients are similar on weekdays and weekends, although large intra-patient variations occur. Future quantification of oral intake during hospitalisation should include as many days as feasible, although not necessarily weekend days, to reflect true intake.