RESUMO
PURPOSE: Is to systematically review the available evidence of the patient's nutritional state before and after orthognathic surgery METHODS: The protocol to the International Prospective Register of Systematic Reviews (PROSPERO; registration No. CRD42020177156). RESULTS: The search strategy yielded a total of 43 articles from all databases. Of the 43 articles, 13 were excluded after an examination of the titles and abstracts, and full-text articles of the remaining 30 studies were reviewed independently for eligibility. Of these 30 studies, 23 were excluded because they did not meet the inclusion criteria. Finally, a total of 7 studies met the inclusion criteria and were processed for critical review CONCLUSION: Patient's body weight and body mass index (BMI) decreases after orthognathic surgery. No significant changes in body fat percentage were observed. The estimated blood loss and the need for blood transfusion increased. No significant changes were observed in hemoglobin levels, lymphocyte counts, total cholesterol levels, and cholinesterase levels between the pre-operative and postoperative periods. Increments in serum albumin levels and total protein counts were observed after orthognathic surgery.