Long-Term Change in both Dietary Insulinemic and Inflammatory Potential Is Associated with Weight Gain in Adult Women and Men

Background: The influence of long-term dietary patterns on weight gain and the underlying potential biological mechanisms are not fully understood. Objective: We prospectively examined the association of changes in 2 empirical hypothesis-oriented dietary patterns (insulinemic and inflammatory) and weight gain over 24 y at 4-y intervals. Methods: We followed 54,397 women in the Nurses' Health Study and 33,043 men in the Health Professionals Follow-Up Study (1986-2010), and computed the empirical dietary index for hyperinsulinemia (EDIH) and empirical dietary inflammatory pattern (EDIP) scores from food frequency questionnaires administered every 4 y. Both scores are weighted sums of 18 food groups, which characterize dietary insulinemic or inflammatory potential based on plasma levels of insulin response or inflammatory biomarkers. We used multivariable-adjusted linear regression to examine 4-y changes in the dietary scores and weight change within the same period. Results: The mean baseline body mass index (BMI, in kg/m(2)) was 25.4. Compared with participants who made minimal dietary changes (quintile 3) over 6 4-y periods; participants who changed their diets toward lower insulinemic or inflammatory potential (quintile 1) gained significantly less weight (in kilograms per 4 y) independent of total energy intake, BMI, physical activity, and smoking status: EDIH: -0.65 (95% CI: -0.73, -0.57), EDIP: -0.29 (-0.37, -0.21) among women; and EDIH: -0.60 (-0.71, -0.49), EDIP: -0.19 (-0.27, -0.07) among men. In contrast, those who changed their diets toward higher insulinemic or inflammatory potential (quintile 5) gained significantly more weight: EDIH: 0.43 (0.36, 0.51), EDIP: 0.15 (0.07, 0.23) among women; and EDIH: 0.49 (0.38, 0.59), EDIP: 0.22 (0.11, 0.33) among men (P-trend < 0.0001 for all comparisons). Associations were stronger among individuals who were overweight or obese, younger, less physically active, and had never smoked. Conclusions: High dietary insulinemic and inflammatory potential is associated with substantial long-term weight gain in adult men and women independent of total energy intake. Dietary patterns with low insulinemic and inflammatory potential may aid in weight gain prevention.