Obesity caused by excessive deposited fat, is generally classified as body mass index (BMI) ≥30 kg/m2. Research regarding the association between dietary advanced glycation end products (dAGEs) and obesity is limited. The aim of present study was to investigate the association between dAGEs and obesity and body composition in Iranian adults. This cross-sectional study included 265 adults aged 18-75 years from Tehran, Iran. Dietary AGEs was estimated using a validated semiquantitative food frequency questionnaire, according to the published food CML–AGE database for 549 routine consumed food items for the Northeastern American multiethnic urban population and was reported by dividing to total energy intake. Dietary intake, socio-demographic data and physical activity status were collected using validated questionnaires and anthropometric characteristics were measured. Body composition was assessed by bioelectrical impedance analysis (BIA) and obesity was defined based on world health organization (WHO) guidelines. The intake of fat and meat were significantly increased in higher tertiles, compared to the first tertile of dAGEs (P <0.001). No association between dAGEs and body composition measures and obesity was observed, however, there were a significant negative association between dAGEs and BMI (body mass index; P=0.01), WC (waist circumference; P=0.01), WHR (waist-to-hip ratio; P=0.03), FFM (fat free mass; P=0.02) and MMI (muscle mass index; P=0.01) in nonlinear models. In conclusion, higher consumption of dAGEs was associated with increased intake of fat and meat and was negatively related to changes in body composition measurements. Therefore dAGEs may connect obesity to diet by energy imbalance.

Recent evidence reported that a higher concentration of 25-hydroxyvitamin D [25[OH] D] has been associated with greater cardiorespiratory fitness [CRF] and muscle strength in both sexes. Low levels of 25[OH]D may be related to hypertrophy of myocardial, high blood pressure, and endothelial dysfunction, which is related to decreased amino acid uptake, prolonged time to peak muscle contraction and relaxation, dysregulation of intracellular Ca2+, muscle weakness, myalgia, impaired neuromuscular function, and hypotonia. Because CRF is defined as a function of maximal cardiac output and maximal arteriovenous oxygen difference, low levels of 25[OH]D may lead to deleterious effects on CRF. Recent findings also indicated vitamin D3 supplementation that leads to an increase in muscle fiber especially type 2, the cross-sectional area of muscle fibers, and improved muscle strength. In this chapter, we will systematically review the observational studies and randomized controlled trials that evaluated the association of vitamin D with CRF and muscle strength.