Clinical impact of Mediterranean-enriched-protein diet on liver size, visceral fat, fat mass, and fat-free mass in patients undergoing sleeve gastrectomy

Abstract

Background: Weight loss before laparoscopic sleeve gastrectomy (LSG) is desirable because it can reduce visceral fat and liver size thereby facilitating the surgical procedure. Preoperative very-low-energy diets have been demonstrated to decrease weight, visceral fat, and liver size. However, no studies have been conducted using the Mediterranean-protein-enriched diet (MPED) or on the amount of preoperative weight loss attributed to the loss of fat-free mass (FFM).

Objectives: To evaluate the effect of the MPED on weight, visceral fat, liver size, fat mass (FM), and FFM in obese patients undergoing LSG.

Setting: University Hospital, Italy.

Materials and methods: Obese male patients (n = 37) with a mean body mass index (BMI) of 45.2 kg/m(2) scheduled for LSG underwent an 8-week preoperative MPED. Their weight, visceral fat, body composition, liver size, and biochemical and metabolic patterns were measured before and after the diet. Patient compliance was assessed by the presence of ketonuria and weight loss. Qualitative methods (5-point Likert questionnaire) were used to measure diet acceptability and side effects.

Results: We observed highly significant decreases in weight, liver size, visceral fat, and FM; however, there was no significant reduction in FFM. All tested patients showed a high frequency of acceptability and compliance in following the diet, and no secondary effects were observed.

Conclusion: Based on our findings, we were able to support the hypothesis that MPED might be associated with significant reductions in weight loss, FM, and liver size without a significant loss of FFM.

Keywords: Bioelectrical impedance analysis; Fat-free mass; Laparoscopic sleeve gastrectomy; Liver size; Mediterranean diet; Nutritional assessment; Preoperative diet.