Associations between early improvements in atherogenic lipids and reported dietary changes after RYGB: a pilot exploratory analysis in women with type 2 diabetes.

INTRODUCTION: Roux-en-Y Gastric Bypass (RYGB) is considered a metabolic surgery due to its early effects on obesity-related dysfunctions, including dyslipidemia. However, some studies suggest that these improvements may be reproduced by dietary changes, primarily calorie restriction. We evaluated whether early post-RYGB changes in dietary intake are associated with improvements in the plasma lipid profile in women with Type 2 Diabetes (T2D). METHODS: We analyzed retrospective paired data from women in the SURMetaGIT cohort at baseline and 3-months after RYGB. Dietary intake was assessed by 7-day food records, summarized as F&V (Fruits/legumes/Vegetables) and HFSS (high-fat/sugar/sodium) food groups, and quantified for energy, macronutrients, and fiber using Nutrabem®. Usual intake was estimated using the Multiple Source Method and adjusted for energy. Plasma lipids included total cholesterol, LDL-c, HDL-c, non-HDL-c, VLDL, and triglycerides. Paired comparisons, correlations, and multivariable linear regression were used to evaluate associations between dietary changes and lipid outcomes. RESULTS: Post-RYGB, patients exhibited a significant decrease in pro-atherogenic lipids. These changes did not correlate with variations in energy, macronutrient, or food-group intake. Conversely, HDL-c showed an independent positive association with phytosterols (β = 0.34, 95% CI: 0.10-0.59; p = 0.007) and a negative association with trans fatty acid intake (β = -0.44, 95% CI:0.82 to -0.06; p = 0.025). CONCLUSION: Early pro-atherogenic lipid improvements in women with T2D after RYGB showed no association with changes in reported energy macronutrient or broad food group intake. Nevertheless, trends in HDL-c were associated with intake of phytosterols and trans fatty acids, suggesting a potential role for dietary counseling to optimize HDL-c after RYGB.