ABSTRACT. Background. Low levels of energy expenditure and aerobic fitness have been hypothesized to be risk factors for obesity. Longitudinal studies to determine whether energy expenditure influences weight gain in whites have provided conflicting results. To date, no studies have examined this relationship in blacks or whether aerobic fitness influences weight gain in white or black children.Methods. One hundred fifteen children, 72 white (55 girls and 17 boys) and 43 black (24 girls and 19 boys) were recruited for this study. Aerobic fitness, resting, total, and activity-related energy expenditure and body composition were measured at baseline. The children returned annually for 3 to 5 repeated measures of body composition. The influence of the initial measures of energy expenditure and fitness on the subsequent rate of increase in adiposity was examined, adjusting for initial body composition, age, ethnicity, gender, and Tanner stage. Because 20 children did not attain maximum oxygen consumption, the sample size for the combined analysis was 95.Results. Initial fat mass was the main predictor of increasing adiposity in this cohort of children, with greater initial fat predicting a higher rate of increase of adiposity. There was also a significant negative relationship between aerobic fitness and the rate of increasing adiposity (F 1,82 ‫؍‬ 3.92). With every increase of .1 L/minute of fitness, there was a decrease of .081 kg fat per kg of lean mass gained. None of the measures of energy expenditure significantly predicted increasing adiposity in white or black children.Conclusions. Initial fat mass was the dominant factor influencing increasing adiposity; however, aerobic fitness was also a significant independent predictor of increasing adiposity in this cohort of children. Resting, total, or activity-related energy expenditure did not predict increasing adiposity. It seems that aerobic fitness may be more important than absolute energy expenditure in the development of obesity in white or black children. Pediatrics 2000;106(4). URL: http://www. pediatrics.org/cgi/content/full/106/4/e50; energy expenditure, fitness, longitudinal, obesity.

No abstract

This study examined changes in postprandial lipemia in endurance-trained people during a short interruption to training. Nine men and one woman (ages 18-55 yr) undertook fat tolerance tests after 15 h, 60 h, and 6.5 days without exercise. The test meal (1.2 g fat, 1.1 g carbohydrate, 66 kJ/kg body mass) was consumed after a 12-h fast. Postprandial lipemia increased rapidly with detraining (area under plasma triacylglycerol vs. time curve: 8.42 +/- 1.40, 11. 35 +/- 1.38, and 11.97 mM x 6 h at 15 h, 60 h and 6.5 days, respectively). In the fasted state, plasma triacylglycerol concentration (0.85 +/- 0.15, 1.09 +/- 0.12, and 1.10 +/- 0.11 mM at 15 h, 60 h and 6.5 days, respectively) and the ratio of total cholesterol to high-density-lipoprotein cholesterol increased with detraining. Values were significantly higher at 60 h and 6.5 days than values at 15 h ( P < 0.05) for each of these three variables. The serum insulin response was higher ( P < 0.05) at 6.5 days than at 15 h (81.6 +/- 11.3, 87.6 +/- 11.4, and 94.5 +/- 9.4 microIU/ml x 6 h at 15 h, 60 h, and 6.5 days, respectively). Frequent exercise is needed to maintain a low level of postprandial lipemia and insulinemia in trained people.

Monitoring dietary intake patterns among children is important in order to explore and prevent the onset of adult health problems. The aim of the present study was to compare children's dietary intakes with national recommendations and to determine whether sex or ethnic differences were evident. This was done using a methodology that allows assessment of intake from the major components of the Food Guide Pyramid developed by the United States Department of Agriculture (USDA: ). The sample studied included 110 African-American and Caucasian males and females (mean age 9·9 years, BMI 20·1 kg/m2) from Birmingham, AL, USA, who were participating in a study investigating the development of obesity. Dietary data were based on three 24 h recalls and food group intake was determined using the USDA Pyramid Servicing Database. The results indicated that a high percentage of subjects failed to meet the recommended number of servings from each of the food groups. For example, only 5 % and 9 % met fruit and dietary group recommendations respectively. Consumption of foods from the Pyramid ‘tip’ (including discretionary fat and added sugar) contributed almost 50 % of the diet. African-Americans were more likely to meet requirements for the meat group, with a higher proportion of Caucasians meeting dietary recommendations. Males were more likely to meet the vegetable group guidelines although females consumed more energy per day from discretionary fat. In conclusion, these results suggest that implementation of nutrition education programmes may be important for promoting healthy nutrition among American children.