Changes in Nutrient Intake, Biochemical Parameters, Diet Quality, and Eating Behavior 6 Months After Sleeve Gastrectomy: A Multi-Dimensional Assessment

Background: This study aimed to evaluate multidimensional postoperative changes in nutrient intake, body composition, biochemical parameters, diet quality, and eating behavior during the first 6 months following sleeve gastrectomy (SG). Methods: This prospective observational study included 55 adults who underwent SG at a specialized obesity clinic in Ankara, Turkey. Eating behavior (TFEQ-TR21), diet quality (HEI-2010), dietary intake, anthropometric measurements, and biochemical parameters were assessed preoperatively and at 6 months postoperatively. Results: Six months after SG, total energy intake decreased markedly, with significant reductions in carbohydrate and fiber intake, while the proportion of energy from protein increased ( p < 0.001). Eating behavior improved, with reduced uncontrolled and emotional eating and higher cognitive restraint. Diet quality improved, reflected by a higher Healthy Eating Index-2010 score ( p < 0.001). Body weight, waist circumference, fat mass, fasting blood glucose, HbA1c, triglycerides, ALT/AST, and uric acid decreased, whereas calcium and vitamin B12 increased significantly. Conclusion: SG produced early improvements in diet quality, eating behavior, body composition, and metabolic status; however, low fiber and reduced intake of key micronutrients suggest persistent nutritional vulnerability. These findings highlight concurrent metabolic recovery and ongoing nutritional risk, supporting the need for larger, long-term studies to evaluate sustained dietary adequacy and metabolic outcomes.