Effect of Increased Physical Activity and Stopping Evening Snacking in Metabolic Health in Youth With Prediabetes

Poor nutrition in addition to a lack of physical activity play significant roles in childhood T2D development, primarily by negatively affecting adiposity and insulin action in concert with other T2D risk factors. Many aspects of nutrition, including frequency of eating, were examined in relation to obesity/increased adiposity and T2D risk. Previous studies suggest increased snacking may cause overeating, and potentially lead to weight gain.

Findings from adolescents in the 2005-2016 National Health and Nutrition Examination Survey (NHANES), showed those with overweight/obesity consume more snacks per day (1.85 and 1.97 snacks per day, respectively) and more calories per snack (305 and 340 kcal/snack, respectively) than their normal-weight peers (1.69 and 262 kcal/snack).Snack consumption in adolescents is also correlated with higher daily energy intake, lower fruit/vegetable intake, along with more frequent fast-food and sugar-sweetened beverage consumptions. The timing of snacking occasions has also emerged as a potential confounder. Among adults, greater evening snacking was associated with higher BMI and higher obesogenic dietary index (e.g., intake of fast food, etc.) while greater morning snacking was associated with increased fruit and vegetable consumption. Having a bedtime snack was associated with increased odds of overweight/obesity (1.47, 95% CI: 1.34-1.62) in Japanese women. Evening snacking was also shown to be independently correlated with overweight/obesity in Italian adolescents (RR 3.12, 95% CI: 1.17-8.34). In the Healthy Growth Study, children who had high-energy intake at dinner and evening snacking were more likely to skip breakfast - a metabolically unhealthy habit.

Also, despite the known metabolic benefits of physical activity, only 1 in 4 adolescents achieve recommended daily physical activity goals (60-min, moderate-to-vigorous physical activity (MVPA)/day).Both snacking and exercise may also affect metabolic health by independently modulating gene expression levels of critical metabolic pathways and subsequently intracellular signaling. Metabolic dysregulation resulting in altered plasma concentrations of several amino acids (e.g., higher branch-chain amino acid and lower glycine concentrations, etc.) was associated with insulin resistance.

Therefore, targeted interventions towards evening snacking and increased physical activity may prove beneficial in adolescents with prediabetes by preventing progression to T2D.

• index for fat disposal (ISI [FFA]) during oral glucose tolerance test [Time frame: At week 9-10 following completion of 8 weeks of intervention period]
• HbA1c [Time frame: At week 9-10 following completion of 8 weeks of intervention period]
• Percentage of adiposity (percent body fat) [Time frame: At week 9-10 following completion of 8 weeks of intervention period]
• Amino acid concentrations [Time frame: At week 9-10 following completion of 8 weeks of intervention period]
• Adiponectin [Time frame: At week 9-10 following completion of 8 weeks of intervention period]
• C-reactive protein (CRP) [Time frame: At week 9-10 following completion of 8 weeks of intervention period]
• TNF-alpha [Time frame: At week 9-10 following completion of 8 weeks of intervention period]
• Interleukin 6 (IL-6) [Time frame: At week 9-10 following completion of 8 weeks of intervention period]
• Gene expression levels of critical pathways [Time frame: At week 9-10 following completion of 8 weeks of intervention period]
• Total energy expenditure [Time frame: At week 9-10 following completion of 8 weeks of intervention period]