Obesity caused by excessive deposited fat is generally classified as BMI ≥ 30 kg/m2. Research regarding the association between dietary advanced glycation end products (dAGE) and obesity is limited. The aim of the present study was to investigate the association between dAGE and obesity and body composition in Iranian adults. This cross-sectional study included 265 adults aged 18–75 years from Tehran, Iran. dAGE were estimated using a validated semi-quantitative FFQ, according to the published food carboxymethyl lysine–AGE database for 549 routinely consumed food items for the Northeastern American multiethnic urban population, and were reported by dividing total energy intake. Dietary intake, sociodemographic data and physical activity status were collected using validated questionnaires, and anthropometric characteristics were measured. Body composition was assessed by bioelectrical impedance analysis, and obesity was defined based on WHO guidelines. The intake of fat and meat was significantly increased in higher tertiles, compared with the first tertile of dAGE (P < 0·001). No association between dAGE and body composition measures and obesity was observed; however, there was a significant negative association between dAGE and BMI (BMI; P = 0·01), waist circumference (P = 0·01), waist:hip ratio (P = 0·03), fat-free mass (P = 0·02) and muscle mass index (P = 0·01) in non-linear models. In conclusion, higher consumption of dAGE was associated with increased intake of fat and meat and was negatively related to changes in body composition measurements. Therefore, dAGE may connect obesity to diet by energy imbalance.

The amount and the type of dietary protein could play a role in determining the quantity of skeletal muscle mass. The aim was to examine the relationship between the type of protein intake and the level of muscle mass in healthy omnivorous and vegetarian Caucasian women. The design of the present study was an observational and cross-sectional study. Twenty-one omnivores (Om) and nineteen vegetarians (Ve) were recruited. Muscle mass index (urinary creatinine), dietary intake (5 d dietary records) and biochemical analyses (hormone, phyto-oestrogen and lipid profiles) were obtained. We found differences between groups for muscle mass (Ve: 18 kg v. Om: 23 kg; P = 0·010), muscle mass index (Ve: 6·7 kg/m2v. Om: 8·3 kg/m2; P = 0·002), animal protein intake in g/d (P = 0·001) and in g/kg body weight per d (P = 0·003), plant protein intake in g/d (P = 0·015) and in g/kg body weight per d (P = 0·007), the animal:plant protein intake ratio (P = 0·001) and sex hormone-binding globulin (SHBG) (P = 0·001). Muscle mass index still correlated with animal protein intake in g/d (P = 0·001) and in g/kg body weight per d (P = 0·008), and the animal:plant protein intake ratio (P = 0·007) even after controlling for SHBG and plant protein intake. Finally, animal protein intake (g/d) was the independent predictor of muscle mass index (adjusted r2 0·42). Thus, a vegetarian diet is associated with a lower muscle mass index than is an omnivorous diet at the same protein intake. A good indicator of muscle mass index in women seems to be animal protein intake.