How Healthy Diet Prevents Obesity

Cochrane

We included 153 RCTs, mostly from the US or European countries. Thirteen studies were carried out in countries with upper-middle-income countries (UMIC: Brazil, Ecuador, Lebanon, Mexico, Thailand, Turkey, American-Mexican border region) and one study in a country with low-middle income (lower-middle -income country, LMIC: Egypt). The majority of studies (85) targeted children aged 6 to 12 years.

Children aged 0 to 5 years: the evidence based on 16 RCTs (n = 6,261) that diet-related interventions in combination with interventions to increase physical activity reduced the BMI compared to a control group was moderate (mean difference ( MD) -0.07 kg / m2, 95% confidence interval (CI) -0.14 to -0.01), there was a similar effect (11 RCTs, n = 5,536) with the egMI score (MD -0.11, 95% CI -0.21 to 0.01). Neither diet-related interventions (moderate reliability of the evidence) nor interventions to increase physical activity alone (high reliability of the evidence) reduced the BMI compared to a control group (interventions to increase physical activity alone: ​​MD -0.22 kg / m2, 95% CI -0.44 to 0.01) or the egMI score (nutrition-related interventions alone: ​​MD -0.14, 95% CI -0.32 to 0.04; interventions to increase physical activity alone: ​​MD 0 , 01, 95% CI -0.10 to 0.13) in children aged 0 to 5 years.

Children aged 6 to 12 years: Based on 14 RCTs (n = 16410), there is evidence of moderate reliability that interventions to increase physical activity could reduce the BMI compared to a control group (MD - 0.10 kg / m2, 95% CI -0.14 to -0.05). However, there is evidence of moderate reliability that it had little or no influence on the egMI score (MD -0.02, 95% CI -0.06 to 0.02). There is evidence of low reliability based on 20 RCTs (n = 24,043) that nutrition-related interventions in combination with interventions to increase physical activity, compared to a control group, reduce the e.g. MI score (MD -0.05 kg / m2 , 95% CI -0.10 to -0.01). There is evidence of high trustworthiness that nutrition-related interventions, compared to a control group, have little influence on the egMI score (MD -0.03, 95% CI -0.06 to 0.01) or the BMI (-0 .02 kg / m2, 95% CI -0.11 to 0.06).

Children between the ages of 13 and 18: There is very little evidence that interventions to increase physical activity reduced the BMI compared to a control group (MD -1.53 ​​kg / m2, 95% CI -2.67 to -0.39; 4 RCTs; n = 720); and there was evidence of low trustworthiness for a reduction in the egMI score (MD -0.2, 95% CI -0.3 to -0.1; 1 RCT; n = 100). On the basis of eight RCTs (n = 16,583) there is evidence of low trustworthiness that nutrition-related interventions in combination with interventions to increase physical activity, compared to a control group, have no influence on the BMI (MD -0.02 kg / m2, 95% CI -0.10 to 0.05) or e.g. MI-Score (MD 0.01, 95% CI -0.05 to 0.07; 6 RCTs; n = 16543). Evidence based on two RCTs (low trustworthiness of the evidence; n = 294) showed that diet-related interventions had no effect on BMI.

Direct comparisons of interventions: Two RCTs reported data directly comparing diet-related interventions or interventions to increase physical activity or combination interventions in children aged 6 to 12 years. These reported no differences.

The results of all three age groups showed heterogeneity, which could not be fully explained by the timing or duration of the interventions. Where reported, interventions appeared to have no adverse effects (16 RCTs) or to aggravate health inequalities (gender: 30 RCTs; socio-economic status: 18 RCTs), although relatively few studies examined these factors.

Carrying out the searches again in January 2018 yielded 315 additional entries with reference to studies with potential relevance for this review, which will be included in the synthesis in the next update.