Metabolic effects, safety, and acceptability of very low-calorie ketogenic dietetic scheme on patients candidates to bariatric surgery

Background: Previous studies have demonstrated significant advantages from a preoperative dietetic regimen for candidates to bariatric procedure. Objectives: Evaluation of safety, efficacy, and acceptability of a very low-calorie ketogenic diet in patients before bariatric surgery. Setting: University Hospital. Methods: A standardized 30-day sequential preoperative diet regimen has been analyzed, optimizing metabolic response with gradual carbohydrate reintroduction. Patients were given a dedicated KetoStationkit, for use during the first 10 days of the scheme, followed by a hypocaloric scheme for 20 days. The study group underwent routine laboratory tests and anthropometric measurements (percent weight loss, body mass index, waist circumference) at enrollment (T0), after 10 days (T1), and after 30 days (T2). Ketone body levels were measured in the plasma and urine. Results: Between January 2015 and September 2015, 119 patients were included in the study. Mean body mass index was 41.5 ± 7.6 kg/m2. Weight, body mass index, and waist circumference at T0 and T1, T0 and T2, and T1 and T2 decreased significantly (P<.05). A bioelectrical impedance assay determined a significant reduction in visceral fat at T1 and T2. We observed a significant (P<.05) improvement in several clinical parameters, including glycemic and lipid profile parameters. We also observed a mean 30% reduction in liver volume. The majority of patients declared satisfied or very satisfied. The adverse effects were mild, of short duration, and not clinically relevant. Conclusion: Our results confirm the acceptability, safety, and significant advantage of a very low-calorie ketogenic diet for reducing weight and liver volume of patients in preparation for bariatric surgery.