LB085 - LARGER GASTRIC VOLUME RESECTION PREDICTS LOWER MICRONUTRIENT INTAKE IN THE EARLY POST-OP PHASE, YET SHOWS NO DIRECT CORRELATION WITH WEIGHT LOSS SUCCESS IN SG PATIENTS

LB085

LARGER GASTRIC VOLUME RESECTION PREDICTS LOWER MICRONUTRIENT INTAKE IN THE EARLY POST-OP PHASE, YET SHOWS NO DIRECT CORRELATION WITH WEIGHT LOSS SUCCESS IN SG PATIENTS

B. N. YÖRÜK^1,*, S. DEMİR FİLİZ²

¹Nutrition and Dietetics, CAN Prıvate Hospital, ²Nutrition and Dietetics, Izmir Tinaztepe University, İZMİR, Türkiye

 

Rationale: Laparoscopic sleeve gastrectomy (SG) is one of the most common bariatric procedures due to its effectiveness in promoting weight loss and improving metabolic outcomes. During SG, a large portion of the stomach is removed, but the volume of resected tissue can vary considerably between patients. This anatomical variability may influence early postoperative outcomes such as nutritional intake, body composition changes, and quality of life, yet it has received limited attention in the literature. While weight loss outcomes like %EWL and %TWL are well studied, the role of gastric resection volume in shaping early nutritional and physiological responses remains unclear. This study investigates the relationship between resected gastric volume and early changes in diet and body composition during the first 60 days after SG.

Methods: Study design and setting: A prospective observational study conducted between June and December 2024 at M*** Private Hospital, Turkey.

Participants: Patients (n = 36) aged 18–60 years with BMI ≥30 kg/m² who voluntarily underwent sleeve gastrectomy by the same surgeon.

Eligibility criteria:

Included: No prior bariatric surgery, no chronic diseases or regular medication, non-smoker, non-alcohol user, failed previous diet/exercise attempts

 Excluded: Age <18 or >60 years, BMI <30 kg/m²,Smoking, alcohol use, Diagnosed comorbidities or drug use

Data collection timeline: Day 0, 15, 30, and 60 post-op

Measurements:

•Gastric volume (mL): measured intraoperatively (KARL STORZ GmbH & Co. KG, 2011),

•Dietary intake: 3-days food records, analyzed with BEBIS 9.0,

•Body composition: BMI, fat mass (%), FFM via BIA,

Sample size calculation: Based on power analysis (G*Power, α = 0.05, power = 80%, effect size = 0.29), a minimum of 33 participants was required.

Ethical approval: MUKCE2024/37, İzmir Tınaztepe University Non-interventional Ethics Committee

Results: Larger gastric resection volume was significantly associated with greater reductions in fat-free mass and total body water but showed no consistent relationship with percentage of weight loss (%EWL, %TWL). The strongest correlations between resected gastric volume and nutrient intake were observed on postoperative Day 15, particularly for total dietary fat and sodium, both showing weak to moderate inverse associations. However, these relationships diminished by Day 30 and were no longer evident by Day 60. This suggests that the early postoperative phase may be a critical window where gastric volume influences dietary intake patterns. Over time, individual adaptation, diet progression, and clinical guidance may override the anatomical effect of gastric resection on nutritional behavior. Continuous dietary monitoring and early nutritional counseling remain essential, especially within the first month post-surgery.

Conclusion: This prospective study explored whether the volume of resected stomach during sleeve gastrectomy impacts early nutritional status, body composition, and quality of life. Larger gastric volumes were significantly associated with greater loss in fat-free mass and body water, but not with weight loss success metrics (%EWL, %TWL). Micronutrient and macronutrient intakes showed weak inverse trends at Day 15, especially for fat and sodium, but these effects diminished by Day 60.Findings emphasize the importance of early nutritional monitoring, not just based on weight loss but also on body composition and dietary quality. This poster is a reminder that in bariatric care, “smaller stomach” doesn’t always mean “better outcomes”—nutrition matters, early.

References: Al Khalifa K, Hinton A, Nawras A, et al. Impact of resected gastric volume on early weight loss after sleeve gastrectomy. Obes Surg. 2021;31(1):78–85.

Felsenreich DM, Langer FB, Gero D, et al. Weight loss, nutritional deficiencies, and quality of life after sleeve gastrectomy—long-term results. Obes Surg. 2021;31(1):224–231.

Zhang Y, Wang Y, Ren W, et al. Association between gastric sleeve volume and postoperative outcomes: a prospective cohort study. Int J Surg. 2023;112:138–144

Disclosure of Interest: None declared