Objectives Investigation of whether the duration of fasting preoperatively has an impact on pain and return to normal function after tonsillectomy To investigate the impact of the duration of preoperative fasting on pain and return to normal function after tonsillectomy. Design Retrospective study with surgeon blinded to the participants undergoing tonsillectomy with or without adenoidectomy Setting University teaching hospital, Sydney, Australia Participants A total of 174 children (n=174) ages 4-12 years old between February 2017 to April 2020 were enrolled. The children were randomised to receive instructions either from the staff at the hospital (n=90) or by the anaesthetist (n=84) in terms of exact pre-operative fasting. Main Outcome measures Fasting times, clear liquid caloric intake 2 hours prior to surgery and Parents Postoperative Pain Measures (PPPM) were documented and analysed. Secondary measures of analgesia usage, number of postoperative nausea or vomiting events were also analysed. Results Observed difference were noted between the instructed fasting period and the actual fasting period. Significant difference in PPPM scores was noted between the Hospital group and the juice group (p<0.001). No significant difference was noted at first to 3rd day (p=0.11) or by the 8th to 10th postoperative day (p=0.93). There was no difference in oxycodone usage between the two groups (p=0.52), or in postoperative nausea and vomiting (p=0.43) Conclusions Significantly lower PPPM scores were noted on day of surgery in the group that had fasting minimised. The effects appeared to trend in a positive manner but larger number of cases need to be performed for results to be of greater significance. Further research is required into the impact of caloric nutrition to enhance recovery after tonsillectomy.