Energy and macronutrient consumption of elementary school children served modified lower fat and sodium lunches or standard higher fat and sodium lunches.

OBJECTIVE: To determine the energy and macronutrient consumption of elementary school children served modified lower fat and sodium or typical higher fat and sodium school lunches. DESIGN: The intervention school received lunches with < 30% of energy from fat and < 1000 mg sodium. The control school received typical lunches with 35% of energy from fat and > 1000 mg sodium. Served lunches were analyzed from menus and consumed lunches were analyzed using USDA plate waste methodology. SUBJECTS: Eighty intervention and 80 control subjects matched for ethnicity and economic status. RESULTS: Intervention school menus were significantly lower for energy, sodium, and fat compared to the control school. From analysis of plate waste, children from both schools consumed approximately 25% less energy than served (p < 0.05). Consumption of fat as a percentage of total energy and consumption of sodium was significantly less for the intervention compared to the control school. Compensation for the lower fat meals by the intervention school children (eating greater portions of high fat items) was not evident as the percentage of energy from fat consumed was only 1.3% greater than the percentage which was served. CONCLUSIONS: Lunch meals in this study were consumed as served. Intervention school children served lower fat and sodium meals consumed less fat and sodium than control school children and did not selectively eat only higher fat and sodium items.

Nutrition and physical activity program to attenuate obesity and promote physical and metabolic fitness in elementary school children.

Obesity and low levels of physical and metabolic fitness are risk factors for cardiovascular disease and diabetes. The purpose of this investigation was to attenuate obesity and improve physical and metabolic fitness in elementary school children. Schools have the opportunity, mechanisms, and personnel in place to deliver nutrition education, fitness activities, and a school food service that is nutritious and healthy. Cohorts from grades 3 to 5 in two school districts in rural Nebraska (Intervention/Control) participated in a 2-year study of physical activity and modified school lunch program. Data collection for aerobic capacity, body composition, blood chemistry, nutrition knowledge, energy intake, and physical activity was at the beginning and end of each year. Int received enhanced physical activity, grade specific nutrition education, and a lower fat and sodium school lunch program. Con continued with a regular school lunch and team sports activity program. At year 2, Int lunches had significantly less energy (9%), fat (25%), sodium (21%), and more fiber (17%). However, measures of 24-hour energy intake for Int and Con showed significant differences for sodium only. Physical activity in the classroom was 6% greater for Int compared to Con (p < 0.05) but physical activity outside of school was approximately 16% less for Int compared to Con (p < 0.05). Body weight and body fat were not different between schools for normal weight or obese children. No differences were found for cholesterol, insulin, and glucose; however, HDL cholesterol was significantly greater and cholesterol/HDL was significantly less for Int compared to Con (p < 0.05). It appears that compensation in both energy intake and physical activity outside of school may be responsible for the lack of differences between Int and Con.

Influence of degree of obesity on loss of fat-free mass during very-low-energy diets.

This study examined the influence of initial degree of obesity on loss of fat-free mass (FFM). One hundred twelve obese females participated in a series of very-low-energy diet (VLED) clinical trials. Obesity groups were determined by three common methods: percent body fat, body mass index, and weight. Within each group, subjects were classified into low-, intermediate-, and high-obesity groups. As expected, the high-obesity group lost comparable amounts or more weight and more fat weight than the low- and intermediate-obesity classifications for each group. The high-obesity group lost approximately 2% more FFM (P < 0.05) compared with the low and intermediate group when subjects were grouped by body mass index and weight and showed no differences between classifications when subjects were grouped by percent body fat. No differences were found between classifications for ratios of FFM to weight loss regardless of how subjects were grouped. Thus, the degree of obesity does not seem to affect loss of FFM.

Very low calorie diet with concurrent versus delayed and sequential exercise.

Obese females undergoing very-low-calorie diet (VLCD) were studied for 12 weeks to determine the effects of concurrent vs delayed and sequential exercise. Subjects were assigned to one of six groups: control (C) n = 28; endurance exercise (EE) n = 18; weight training (WT) n = 26; endurance exercise plus weight training (EEWT) n = 21; control for 4 weeks with subsequent EE (C4EE) n = 10; WT for 4 weeks with sequential EE (WT4EE) n = 12. EE was performed 3 days a week using five weight lifting exercises. Loss in body weight did not differ between groups. Expressed as a ratio of fat-free mass (FFM) to weight loss WT4EE showed a 8.1%, 9.7%, and 11.4% difference compared to EE, C4EE, and C, respectively (P < 0.05). WT4EE also showed significant increases from baseline of 8.2% in aerobic capacity (L/min) and 12.5% in the strength index (SI/kg FFM). WT4EE showed the smallest decrease of all groups in resting metabolic rate of 6.1% of the baseline value; however, this decrease was significant. Although WT4EE showed some favorable changes from baseline, the magnitude of the changes between groups was small. There were no significant differences found between C4EE and the other study groups. Thus, the delay or sequential use of exercise during VLCD provided only small differences for WT4EE compared to the other groups and any clinical significance for the individual is presently unknown.

Does the amount of endurance exercise in combination with weight training and a very-low-energy diet affect resting metabolic rate and body composition?

Effects of large (LA; 400 min/wk) and moderate (MA; 200 min/wk) amounts of endurance exercise in combination with weight training (3 d/wk) were compared with the effects of no exercise (C) in 23 obese females after a 12-wk, 3360-kJ/d very-low-energy diet (VLED). The LA group lost 6.5 kg more weight, mainly as fat (6.4 kg), than the C group (P < 0.05). No measurable differences were found among groups for decreases in resting metabolic rate (-729 to -1233 kJ/d; NS) or fat-free mass (-2.9 to -3.9 kg; NS). No improvements in aerobic capacity were achieved with the addition of exercise to a VLED (-0.079 to -0.037 L/min; NS). Strength indexes were improved (+16 to +5 kg; P < 0.05) or maintained with exercise (-3 kg; NS) whereas a loss (-9.3 kg; P < 0.05) or maintenance (+4.5 kg; NS) was found for VLED alone. Large amounts of endurance exercise in combination with weight training added to a VLED appear to improve weight and fat loss compared with a VLED alone.

Muscle hypertrophy with large-scale weight loss and resistance training.

The combined effects of exercise and energy restriction on changes in body fat and fat-free mass (FFM) are controversial. This study was conducted to determine whether muscle hypertrophy is possible during weight loss. Fourteen obese females received a 3360-kJ/d liquid diet for 90 d. Seven subjects received a weight training (WT) regimen and seven subjects remained sedentary (C). Biopsy samples were obtained from the vastus lateralis muscle at baseline and after 90 d of treatment. The average weight loss over the 90-d period was 16 kg with approximately 24% of the weight loss from FFM and 76% from fat. The amount and composition of the weight loss did not differ between WT and C groups. The cross-sectional area of slow twitch and fast twitch fibers was unchanged by treatment in C subjects but significantly increased in WT subjects. It appears that weight training can produce hypertrophy in skeletal muscle during severe energy restriction and large-scale weight loss.