Body Composition in Youths Aged 10‒17 Years by Deuterium Oxide Dilution, Air Displacement Plethysmography, and DXA: Validation of the Medical Body Composition Analyzer Bioimpedance Device by a 4-Compartment Model.

BACKGROUND: The medical body composition analyzer (mBCA) incorporates advances in multifrequency technology and has been validated using a 4-compartment (4C) model in adults but not in youths aged <18 y. OBJECTIVES: This study aimed to formulate a 4C model based on 3 reference methods and develop and validate a body composition prediction equation for the mBCA in youths aged 10‒17 y. METHODS: The body density of 60 female and male youths was measured by air displacement plethysmography, total body water by deuterium oxide dilution, and BMC by DXA. Data from the equation group (n = 30) were used to formulate a 4C model. The all-possible-regressions method was used to select variables. The model was validated in a second cohort (n = 30) in a random split design. The accuracy, precision, and potential bias were evaluated by the Bland and Altman procedure. RESULTS: Mean age, weight (W), height (H), waist circumference, and z-score of BMI were 13.6 ± 2.3 y, 54.5 ± 15.5 kg, 156 ± 11.9 cm, 75.5 ± 10.9 cm, and 0.70 ± 1.32 z, respectively. The prediction equation was as follows: FFM in kg (FFMkg) = ([0.2081] ∗ [W] + [0.8814] ∗ [H2cm/RΩ] + [0.2055 ∗ XcΩ])-15.343; R2 = 0.96; standardized root-mean-square error (SRMSE) = 2.18 kg. FFM did not differ between the 4C method (38.9 ± 12.0 kg) and the mBCA (38.4 ± 11.4 kg) (P > 0.05). The relationship between these 2 variables did not deviate from the identity line, was not significantly different from 0, and the slope was not significantly different from 1.0. In the precision prediction model of mBCA, the R2 value was 0.98 and SRMSE was 2.1. No significant bias was found when regressing differences between methods and their means (P = 0.08). CONCLUSIONS: The equation for the mBCA was accurate, precise, had no significant bias, had substantial strength of agreement and could be used in this age group when subjects were preferentially within the constraints of a specified body size.

Interventions for the prevention of weight gain during festive and holiday periods in children and adults: A systematic review.

Some periods during the year, such as festive and summer holiday periods, have been associated with weight gain. We aimed to assess the effect of interventions for the prevention of body weight gain during festive and holiday periods in children and adults. A systematic search was conducted in six databases and supplementary sources until January 4, 2023. We included randomized controlled trials (RCTs), cluster-RCTs, and non-RCTs. Our primary outcome measure was the change in body weight in adults or the change in BMI z-score or BMI percentile in children and adolescents. From 4216 records, 12 primary studies (from 22 reports) met the inclusion criteria-10 from the United States, one from the United Kingdom, and one from Chile. Two studies had a low risk of bias, two moderate, seven high, and one critical risk of bias. The meta-analysis in children included four of seven studies during the summer holidays (six interventions) and showed a mean difference in BMI z-score favoring the intervention group (-0.06 [95% CI -0.10, -0.01], p = 0.01, I2 = 0%, very low certainty evidence). The meta-analysis in adults included five studies during festive periods with a mean difference in weight favoring the intervention group (-0.99 kg [95% CI -2.15, 0.18], p = 0.10, I2 = 89%, very low certainty evidence). This review has highlighted potential interventions to prevent the increase in body weight during holiday periods. More work is needed to improve the quality of the evidence and to extend it to countries outside of the United States and United Kingdom and to the adolescent population.

Poor compliance with school food environment guidelines in elementary schools in Northwest Mexico: A cross-sectional study.

BACKGROUND: In Mexico, 35.5% of school-age children were overweight or obese in 2018. The school food environment is important because children spend a significant part of their time at school and consume one-third to one-half of their daily meals there. In 2014, a Federal Government guideline for the sale and distribution of food and beverages in Mexican schools was published (the AGREEMENT) but the extent of its implementation is not known. METHODS: Descriptive cross-sectional study in a representative, random sample of elementary schools, using the tools of the INFORMAS network. Data collection included: a) an interview with a school authority; b) a checklist of items available in the school canteen; c) a checklist of the school breakfast menu; and d) an evaluation of the physical environment. The main indicators were: percentage of implementation (self-report) of the AGREEMENT and percentage of compliance (researcher verified) with the AGREEMENT (based on tools b and c). RESULTS: 119 schools participated (response rate 87.5%), with 15.1% (95%CI 9.2-22.8) of the schools reporting having fully implemented the AGREEMENT. However, only 1% (95%CI 0-5.3) of the school canteens and 71.4% (95%CI 57.8-82.7) of the school breakfast menus fully complied with the AGREEMENT. A variety of sugar-sweetened beverages and energy-dense, nutrient poor products were found in the school canteens. Further, only 43.7% of the water fountains in schools were functional and 23.4% were clean. In only 24.4% of schools had the school authorities received formal training related to the AGREEMENT and in 28.6% of schools had the parents received information about the AGREEMENT. CONCLUSION: The AGREEMENT has been poorly implemented in elementary schools in Mexico. Actions are needed to encourage and support its full implementation to improve the food environment in Mexican schools.

Preliminary Results of the Planet Nutrition Program on Obesity Parameters in Mexican Schoolchildren: Pilot Single-School Randomized Controlled Trial.

School-based obesity prevention programs are key to promoting healthy habits. The aim of this study was to evaluate the effect of the Planet Nutrition program on BMI z-score and other parameters compared to a control group of Mexican schoolchildren after 9 weeks of intervention. The effect of the summer holidays on the BMI z-score was also evaluated at 23 weeks. A pilot randomized controlled trial design was used and 41 schoolchildren were randomized (21 intervention group and 20 control). The program included 18 nutrition education sessions, 20 physical activity classes and six brochures for parents. At 9 weeks, no significant differences were found between the intervention and control groups in the change in BMI z-score (-0.11, 95% CI -0.23, 0.01). Significant differences were observed in some secondary outcomes: body fat percentage (-1.72, 95% CI -3.42, -0.02), waist circumference (-3.45, 95% CI -5.55, -1.36), physical activity (0.44, 95% CI 0.01, 0.88) and nutrition knowledge (1.15, 95% CI 0.27, 2.03). Summer holidays negatively affected the BMI z-score in both groups, reducing the difference observed between groups at 9 weeks (-0.07, 95% CI -0.22, 0.07). The Planet Nutrition program showed favorable effects in some obesity and lifestyle parameters in the short term.

Effectiveness of the Diabetes Prevention Program for Obesity Treatment in Real World Clinical Practice in a Middle-Income Country in Latin America.

The Diabetes Prevention Program (DPP) is effective for the prevention of type 2 diabetes by weight loss with diet and physical activity. However, there is little evidence as to whether this program could be translated into real-world clinical practice in Latin American countries. The objective of this work was to evaluate the effectiveness of the DPP for the management of overweightness and obesity at 6 and 12 months in clinical practice in Mexico. This was a non-controlled intervention study implemented in five public clinics in northern Mexico. Two hundred and thirty-seven adults aged 45.7 ± 9.9 years with a Body Mass Index (BMI) of 34.4 ± 5.4 kg/m2 received group sessions with an adaptation of the DPP, in addition to nutrition counseling. One hundred and thirty-three (56%) participants concluded the 6 month phase. They showed a significant weight loss, ranging from 2.76 ± 4.76 to 7.92 ± 6.85 kg (p ≤ 0.01) in the clinics. The intention-to-treat analysis showed a more conservative weight loss. Participant retention at the end of 12 months was low (40%). The implementation of the DPP in different public clinics in Mexico was effective in the management of obesity in the short term, but better strategies are required to improve participant retention in the long term.

Effect of the Holiday Season on Weight Gain: A Narrative Review.

Several studies suggest that the holiday season, starting from the last week of November to the first or second week of January, could be critical to gaining weight. This study aims to review the literature to determine the effects of the holidays on body weight. In studies of adults, a significant weight gain was consistently observed during this period (0.4 to 0.9 kg, p < 0.05). The only study in college students found an effect on body fat but not on weight (0.1 kg, p = 0.71). The only study found in children did not show an effect on BMI percentile (-0.4%, p > 0.05) during this period. Among individuals with obesity who attempt to lose weight, an increase in weight was observed (0.3 to 0.9 kg, significant in some but not in all studies), as well as increase in weight in motivated self-monitoring people (0.4 to 0.6%, p < 0.001). Programs focused on self-monitoring during the holidays (phone calls and daily mailing) appeared to prevent weight gain, but information is limited. The holiday season seems to increase body weight in adults, even in participants seeking to lose weight and in motivated self-monitoring people, whereas in children, adolescents, and college students, very few studies were found to make accurate conclusions.