Dietary energy density, metabolic parameters, and blood pressure in a sample of adults with obesity

Several previous studies revealed the role of dietary energy density (DED) in developing obesity and related disorders. However, the possible role of DED in triggering cardiometabolic risk factors of individuals with obesity has not been studied yet. This study aimed to evaluate the association between DED and anthropometric parameters, blood pressure, and components of metabolic syndrome (MetS) (such as glycemic markers, lipid profile, and blood pressure) among individuals with obesity.

In this cross-sectional study, we included 335 adults with obesity (BMI ≥ 30 kg/m²) aged 20-50 years in Tabriz and Tehran, Iran. Dietary intake was assessed by a validated semi-quantitative Food Frequency Questionnaire (FFQ), including 168 food items; then, DED was calculated. MetS was defined based on the guidelines of the National Cholesterol Education Program Adult Treatment Panel III (NCEP-ATP III). Enzymatic methods were used to assess serum lipids, glucose, and insulin concentrations. Blood pressure was measured by sphygmomanometer and body composition by bioelectrical impedance analysis (BIA).

Participants in the higher tertiles of DED had more intake of carbohydrate, dietary fat, saturated fatty acid (SFA), monounsaturated fatty acid (MUFA), polyunsaturated fatty acid (PUFA), and meat, fish, poultry (MFP). Increasing the DED in both methods had no association with systolic blood pressure (SBP), fasting blood sugar (FBS), low-density lipoprotein cholesterol (LDL-C), insulin, triglyceride (TG), and homeostatic model assessment of insulin resistance (HOMA-IR) even after adjustment for confounders. However, diastolic blood pressure (DBP) decreased in second tertile of DED I (β = 0.921, P = 0.004). The quantitative insulin-sensitivity check index (QUICKI) in second tertile of both DED methods had significant positive association with DED. In the second tertile of DED II, while total cholesterol (TC) significantly decreased (P crude = 0.036, P adjusted = 0.024), high-density lipoprotein cholesterol (HDL-C) increased (β = 1.096, p = 0.03). There was no significant changes in biochemical parameters in third tertile of DED I and II even after adjustment for covariates. Also, higher tertiles of DED was associated with reduced prevalence of MetS.

High DED was associated with lower levels of blood pressure and TC but elevated levels of HDL and QUICKI independent of such confounders as age, BMI, sex, and physical activity. Further longitudinal studies are warranted to better elucidate casual associations.