Major dietary patterns and their associations with total weight loss and weight loss composition 2-4 years after sleeve gastrectomy.

Background: Food intakes 1-2 years following bariatric surgery depend more on patients than the surgery's gastrointestinal tract changes. This study aimed to determine the major dietary patterns of patients after the first two years of sleeve gastrectomy and to investigate their associations with total weight loss (TWL) and the proportion of TWL as fat mass (FM) and fat-free mass (FFM) loss.

Methods: This cross-sectional study included 146 patients undergoing sleeve gastrectomy 2-4 years after surgery. Dietary patterns were determined using principal component analysis based on the 19 food groups. The percentage of FM loss relative to TWL (%FML) and FFM loss relative to TWL (%FFML) were calculated. A suboptimal clinical response was defined as a TWL of less than 25%. High FM loss and excessive FFM loss were defined based on the highest tertiles. Linear and logistic regression models were used to derive unstandardized (B) coefficients and odds ratios (OR), with dietary pattern scores serving as both a continuous and a binary variable (higher vs. lower adherence groups based on median).

Results: Two predominant dietary patterns were retained. Each 1-unit increase in the first dietary pattern score characterized by high intakes of fast foods, soft drinks, processed meats, sugar confectionary, salty snacks, grains, and organ meats was associated with higher %FFML (B = 1.99; 95% confidence interval (CI) 0.34, 3.66), lower %FML (B = - 1.84; 95% CI - 3.49, - 0.20), and higher odds of excessive FFM loss (OR = 1.84; 95% CI 1.09, 3.11). Participants with higher adherence to the first dietary pattern had lower %TWL, and greater odds of suboptimal clinical response and excessive FFM loss than those with lower adherence. Each 1-unit increase in score for the second dietary pattern characterized by a high intake of fruits, dairy, vegetables, legumes, eggs, nuts, red meats, poultry, and fish was associated with lower odds of suboptimal clinical response (OR = 0.51; 95% CI 0.31, 0.86).

Conclusion: Patients should be encouraged to modify their diet by reducing the consumption of ultra-processed foods and increasing their intake of high-quality protein sources, fruits, and vegetables to achieve the best postoperative outcome.