The safety, tolerability and clinical impact of pre-operative very low-calorie diet prior to non-bariatric abdominal surgery: a systematic review

Background: The use of pre-operative very low-calorie diets (VLCD) is established within bariatric and gallbladder surgery. However, their use in patients with high BMI and hepatic steatosis (HS) requiring upper abdominal procedures is unclear. This review aims to assess the safety, adherence, and outcomes of a pre-operative VLCD prior to non-bariatric elective surgery.

Methods: A systematic search on PubMed MEDLINE, Embase, Cochrane Central Register of Controlled Trials (CENTRAL), CINAHL and AMED was performed to identify the included studies. Studies were included, if they administered a VLCD to patients undergoing non-bariatric elective surgery and reported on outcomes.

Results: Eight studies were included in this review and all administered a VLCD through either dietician led diet plans or meal replacement shakes. The adherence to the VLCD was heterogeneously measured but was excellent overall with a good safety profile. The VLCD was able to significantly reduce HS and resulted in a less technically difficult operation with reduced intra-operative blood loss. There was no significant impact on intraoperative or early post-operative outcomes.

Conclusion: This review highlights that a VLCD can be administered safely during the pre-operative period and overall adherence is excellent, however heterogeneously measured. There was an overall positive impact on reducing hepatic steatosis, operative difficulty and intraoperative blood loss, however no significant impact on overall morbidity and mortality.