BackgroundOverweight and obesity in children in Mexico was among the countries with the highest prevalence's in the world. Mexico currently has few innovative and comprehensive experiences to help curb the growth of this serious public health problem. Therefore, the aim of this study is to assess the effectiveness of a nutrition and physical activity strategy, called "Nutrition on the Go" ("nutrición en movimiento") in maintaining the BMI values of school children in the State of Mexico.MethodsA two-stage cluster trial was carried out. Sixty schools were selected in the State of Mexico, of which 30 were randomly assigned to the intervention group (IG) and 30 to the control group (CG). A total of 1020 fifth grade school children participated. The intervention strategy aimed to decrease the energy content of school breakfasts and include fruits and vegetables, as well as increase physical activity and the consumption of water during the time spent at school. The strategy was implemented over a 6-month period.ResultsThe estimated probability (EP) of obesity between baseline and the final stage for the IG decreased 1% (Initial EP = 11.8%, 95%CI 9.0, 15.2, final EP = 10.8, 95%CI 8.4, 13.) For the CG, the probability increased 0.9% (baseline EP = 10.6%; 95%CI 8.1, 13.7; final EP = 11.5, 95%CI 9.0, 14.6). The interaction between the intervention and the stage is the average odd time corrected treatment effect, which is statistically significant (p = 0.01) (OR = 0.68, 95%CI 0.52, 091).This represents the interaction between intervention and stage, which is highly significant (p = 0.01) (OR = 0.68; 95%CI 0.52, 091). In addition, girls had a protective effect on obesity (OR = 0.56; 95%CI 0.39, 0.80).ConclusionsThe intervention strategy is effective in maintaining the BMI of school children.

The National Health and Nutrition Survey (ENSANUT 2006, Mexico) collected information about physical activity done by teenagers. An adaptation of IPAQ (International Physical Activity Questionnaire) was used to get data. Sample was integrated by 249241 teenagers. Weekly physical activity or inactivity time information was obtained. Those teenagers who did at least 7 hours of moderated physical activity at week were classified as active, teenagers who did between 4 and less than seven hours of moderated activity as moderately active, and finally those who did less than 4 hours of vigorous or moderated activity in the last week were classified as inactive. Results shows that 35.2% of teenagers are active, 24.4% are moderately active and 40.4% inactive. Time spent by the teenagers watching TV (shows, movies, and playing videogames) was also classified. It was considered as acceptable up to 12 hours in a week, less acceptable between 12 to less than 21 and more than 21 hours as unacceptable. More than 50 % of the teenagers spent daily two hours watching TV or more. Relationship between time watching TV and activity level can't be established. Survey results show that Mexican teenagers are making less moderated and physical activity than recommended. Only 35.2% of teenagers accomplish with the recommendations. To the previous situation it must be added that more than the half of the teenagers spent 12 or more hours in front of the TV screen.