Background/Objectives: Metabolic bariatric surgery is an effective treatment for severe obesity but is associated with an increased risk of postoperative nutritional deficiencies. This study aimed to assess the impact of adherence to the Mediterranean diet on selected laboratory parameters and excess weight loss after bariatric surgery. Methods: Eighty adults with obesity were evaluated before and 6 months after surgery. Based on dietary questionnaires, patients were classified as adhering to the Mediterranean diet (n = 32) or not adhering (n = 48). Laboratory parameters, including vitamin D, vitamin B12, folic acid, iron, ferritin, calcium, hemoglobin, and total protein, were assessed pre- and postoperatively. Excess weight loss percentage (EWL%) was calculated using standard methodology. Results: Postoperatively, vitamin D and total protein levels increased in both groups, with median increases of 9.45 ng/mL and 1.1 g/dL, respectively. A significant increase in iron concentration was observed only in Mediterranean diet adherents (median +24 µg/dL), while a decrease was noted in non-adherent patients (−4 µg/dL). Iron deficiency and iron-deficiency anemia occurred exclusively in the non-Mediterranean diet group (10.4% vs. 0%). Median EWL% was higher in Mediterranean diet adherents (44% vs. 31%), although the difference was not statistically significant. Conclusions: Adherence to the Mediterranean diet may reduce the risk of iron deficiency after bariatric surgery, whereas total protein concentration alone appears insufficient for assessing nutritional status or weight loss effectiveness.

Introduction and aim of the study: The majority of bariatric procedures are performed in women of reproductive age, which has resulted in a growing number of pregnancies following bariatric surgery. The purpose of the study was to analyze whether obstetricians-gynecologists taking care of pregnancies after bariatric surgery possess sufficient knowledge about it. Materials and method: The study was conducted in the form of a multiple choice, anonymous survey, conducted among 123 certified specialists in obstetrics and gynecology and 37 residents training in obstetrics and gynecology. The questions were related to supplementation of vitamins and micronutrients, the appropriate time interval between bariatric surgery and pregnancy, dietary recommendations, diagnosing gestational diabetes mellitus, and risks for the fetus following bariatric surgery. Results: The majority of participants did not know the correct answers, with only one participant who answered correctly all the questions provided. There was a correlation between giving correct answers to the question about dietary recommendations and the question about risks existing during a pregnancy after bariatric surgery. Only 30% of participants knew how gestational diabetes mellitus should be diagnosed in pregnancies after bariatric surgery. Conclusions: To enhance safety for women and their children, it is of utmost importance to implement additional training and educational programs for obstetricians-gynecologists about optimum care for pregnancies after bariatric surgery.