Lipid Metabolism Links Nutrient-Exercise Timing to Insulin Sensitivity in Men Classified as Overweight or Obese.

CONTEXT: Pre-exercise nutrient availability alters acute metabolic responses to exercise, which could modulate training responsiveness. OBJECTIVE: To assess acute and chronic effects of exercise performed before versus after nutrient ingestion on whole-body and intramuscular lipid utilization and postprandial glucose metabolism. DESIGN: (1) Acute, randomized, crossover design (Acute Study); (2) 6-week, randomized, controlled design (Training Study). SETTING: General community. PARTICIPANTS: Men with overweight/obesity (mean ± standard deviation, body mass index: 30.2 ± 3.5 kg⋅m-2 for Acute Study, 30.9 ± 4.5 kg⋅m-2 for Training Study). INTERVENTIONS: Moderate-intensity cycling performed before versus after mixed-macronutrient breakfast (Acute Study) or carbohydrate (Training Study) ingestion. RESULTS: Acute Study-exercise before versus after breakfast consumption increased net intramuscular lipid utilization in type I (net change: -3.44 ± 2.63% versus 1.44 ± 4.18% area lipid staining, P < 0.01) and type II fibers (-1.89 ± 2.48% versus 1.83 ± 1.92% area lipid staining, P < 0.05). Training Study-postprandial glycemia was not differentially affected by 6 weeks of exercise training performed before versus after carbohydrate intake (P > 0.05). However, postprandial insulinemia was reduced with exercise training performed before but not after carbohydrate ingestion (P = 0.03). This resulted in increased oral glucose insulin sensitivity (25 ± 38 vs -21 ± 32 mL⋅min-1⋅m-2; P = 0.01), associated with increased lipid utilization during exercise (r = 0.50, P = 0.02). Regular exercise before nutrient provision also augmented remodeling of skeletal muscle phospholipids and protein content of the glucose transport protein GLUT4 (P < 0.05). CONCLUSIONS: Experiments investigating exercise training and metabolic health should consider nutrient-exercise timing, and exercise performed before versus after nutrient intake (ie, in the fasted state) may exert beneficial effects on lipid utilization and reduce postprandial insulinemia.

Ethnic Differences in the Food Intake Patterns and Its Associated Factors of Adolescents in Kelantan, Malaysia.

OBJECTIVE: The aim of the study was to identify the ethnic differences in dietary patterns and its association with socio-economic, dietary and lifestyle practices among adolescents in Kelantan, Malaysia. METHODS: A population-based study of 454 adolescents aged 12 to 19 years was included. A validated food frequency questionnaire was used to assess dietary patterns and three dietary patterns were identified based on the principal component analysis method. RESULTS: Malay adolescents had significantly higher scores for the Western-based food pattern and local-based food pattern, whereas Chinese adolescents showed higher scores for the healthy-based food pattern. Multivariate analyses show that age and physical activity (PA) levels were positively associated with healthy-based food pattern in Malay (All, p < 0.001), whereas higher consumption of eating-out from home (EatOut) (p = 0.014) and fast food (p = 0.041) were negatively associated. High weekly breakfast skipping (p < 0.001) and EatOut (p = 0.003) were positively associated with a Western-based pattern, whereas age (p < 0.001) and household income (p = 0.005) were negatively associated. Higher frequency of daily snacking (p = 0.013) was positively associated with local-based food pattern. For Chinese adolescents, age (p < 0.001), PA levels (p < 0.001) and maternal education level (p = 0.035) showed positive associations with the healthy-based pattern, whereas high EatOut (p = 0.001) and fast food intakes (p = 0.001) were negatively associated. Higher weekly consumption of EatOut (p = 0.007), fast food (p = 0.023) and carbonated beverages (p = 0.023), and daily snacking practice (p = 0.004) were positively associated with higher Western-based food pattern, whereas age (p = 0.004) was inversely associated. CONCLUSION: This study showed that there were significant differences in dietary patterns and its association factors between Malay and Chinese adolescents. More importantly, these findings suggest that unhealthy dietary and lifestyle practices could increase the risk of adherence to unhealthy Western-based food pattern that is high in fat, sugar and salt contents, and, consequently, increase the risk of developing obesity and metabolic-related disorders during these critical years of growth.

Relationship between anthropometric and dual energy X-ray absorptiometry measures to assess total and regional adiposity in Malaysian adolescents.

The main objective of this paper was to determine the utility of various anthropometric measures to assess total and regional body fatness using dual-energy X-ray absorptiometry (DXA) as the criterion in 454 adolescent boys and girls aged 12-19 years. Multivariable regression analyses of gender-specific and gender-combined models were used to determine anthropometric measures on DXA-derived body fatness models, after adjusting for known confounding biological factors. Partial correlation analyses, after adjusting for age, pubertal growth status and ethnicity in boys and girls, showed that body mass index (BMI), waist circumference (WC), waist-to-hip ratio (WHR), and waist-height ratio (WhtR) were significantly correlated with total body fat (TBF), percent body fat (%BF), android region fat (ARF) and trunk fat (TF) (all p<0.0001). BMI was the greatest independent determinant, contributing 43.8%-80.9% of the total variance for DXA-derived body fatness models. Results confirmed that a simple anthropometric index such as the BMI is a good surrogate indicator of body fat levels in Malay and Chinese adolescents.