General and visceral adiposity in black and white adolescents and their relation with reported physical activity and diet

Abstract

Background: Excess body fat accumulation may begin in youth and is linked with increased risk of cardiovascular disease. Examination of physical activity (PA) and diet behaviours predictive of adiposity may help target efforts to reduce chronic disease risk. Objective: We hypothesized that energy intake (EI) from fat, vigorous PA (VPA), and their interaction would predict body fat percentage (%BF) and visceral adipose tissue (VAT) in youth and that sedentary behaviours and intake of dairy, fruit, vegetable and whole grain foods would be related to adiposity. Design: A cross-sectional, observational study of reported PA and diet behaviours and objective adiposity measures. Subjects: Six-hundred sixty-one healthy black and white adolescents aged 14-18 years. Measurements: Diet by 24-h recalls using Nutrition Data Systems for Research (Minneapolis, MN, USA), VPA by previous day physical activity recalls (PAR), and %BF with dual-energy X-ray absorptiometry. VAT by magnetic resonance imaging for 434 subjects. Results: Reported EI and VPA were positively correlated with each other and were negative predictors of %BF. Time spent watching television or movies and %EI from protein were positive predictors of %BF. Adjusted for EI, none of the independent variables predictive of %BF retained their significance. %BF and VAT were highly correlated (r ¼ 0.73, Po0.0001). EI was the sole and negative predictor of VAT. Conclusions: Higher energy 'throughput', not energy restriction, characterize leaner youths. Youths should be advised to engage in VPA so that they can eat sufficient calories to obtain the nutrients required for optimal health while remaining lean.

Diet vs exercise for the prevention of pediatric obesity: the role of exercise

“…Indeed, recent projects that have measured body composition (rather than body weight) have generally found that fatter youths tend to ingest less energy than leaner youths. 4,7 One explanation for this counter-intuitive finding is that fatter youths under-report their energy intake more than leaner youths. This formulation requires that we assume that fatter youths eat more in the face of data that do not support the assumption, hardly an appropriate scientific attitude.…”

“…11,12 This is consistent with the findings that fatter youths watch more TV, as a surrogate for sedentariness, than leaner youths. 4 Especially noteworthy results have been obtained from recent studies that distinguished moderate PA (3-6 METS) from vigorous PA (46 METS); the breakpoint between moderate and vigorous PA is approximately the difference between brisk walking and jogging-running. 13,14 These studies have shown that the amount of time spent in vigorous PA explained more of the variance in body fatness than did lower intensities of PA.…”

“…4 Although body mass index (BMI) is an effective surrogate index of fatness for epidemiological investigations, the numerator (weight) includes both fat mass and fat-free mass; this is a serious deficiency for several reasons. Most important is the fact that it is the fat tissue, not the lean tissue, which is deleterious to health, as illustrated in a study that showed weight loss to increase mortality rate, whereas fat loss decreased mortality rate.…”

Dietary Sodium, Adiposity, and Inflammation in Healthy Adolescents

“…Pearson' s correlation coefficient was first used to assess the correlations of adiposity, adipokines, and markers of inflammation with potential confounding factors, including Tanner stage, physical activity, birth weight, SES, dietary fat, and sugar-sweetened soft drink and potassium intake. [9][10][11][12]27,28 Only related confounding variables were included in the analyses.…”

Comment on letters by T Wilkin, and D Boniface and J Wardle concerning school-based physical activity

“…However, recent research has found that vigorous PA is associated with lower adiposity, while moderate PA is not (for example, StallmannJorgensen et al 4 ). What can account for this finding?…”