Abstract
Bariatric surgery (BS) effectively manages severe obesity, but postoperative dietary restrictions often lead to nutrient deficiencies, particularly in the first year. This study evaluated dietary intake and serum nutrient status at 6 and 12 months post-BS in 133 patients (sleeve gastrectomy/gastric bypass, 2022-2023). Nutritional assessments were conducted using 24-hour dietary recall, comparing results with the Guidelines for Medical Nutritional Treatment of Overweight/Obesity in China (2021). Total energy intake increased significantly from 6 to 12 months (116.2 ± 433.1 kcal/d, P = 0.02). Carbohydrate contribution rose by 3.0 ± 13.6 energy percentage (en%, P = 0.01), while fat (-1.6 ± 8.9 en%, P = 0.04) and protein (-1.4 ± 6.3 en%, P = 0.01) contributions decreased. Mean protein intake remained below recommendations at both time points (53.5 ± 22.1 g/d vs. 56.4 ± 19.9 g/d), with only 59.4% (6 months) and 53.4% (12 months) meeting criteria. Mean change in consumption from 3 to 6 months, reflecting significant increases, was observed for cereal (24.7 ± 81.1 g/d, P = 0.001), vegetables (57.7 ± 159.8 g/d, P < 0.001) and vegetable oil (2.7 ± 5.9 g/d, P < 0.001). The most common deficiencies in postoperative serum nutrients were those of 25 hydroxyvitamin D (91.7%), ferritin (27.1%), albumin (14.3%) and hemoglobin (12.8%) at 12 months after surgery. Regression analysis showed that gender, surgical type, fat intake and protein powder use were independent predictors of postoperative protein intake. In conclusion, patients demonstrated inadequate nutrient intake and persistent serum deficiencies during the year following surgery. Close monitoring of dietary adherence remains critical throughout the postoperative phase.