Overall, a high prevalence of obesity was found in Ecuadorian children and adolescents, with more than one out of 10 participants having obesity. This high prevalence of obesity is in line with that reported in other international studies, both for South America and Ecuador.1,2 Supporting this notion, the last ENSANUT-2012 reported a lower prevalence of obesity (10.9%) than that observed in this study (12.7%), which indicates a growing upward trend. Although obesity in childhood and adolescence cannot be attributed to a single modifiable factor,6,26 this study further identified several factors related to obesity.

Concerning the factors related to obesity in Ecuadorian children and adolescents, the findings obtained highlight some inequalities in obesity according to sociodemographic factors. For instance, the results revealed that girls were less likely to have obesity than boys were. The same trend was also identified in the analyses stratified by age group. Although these findings were not consistent in LMICs, the prevalence of obesity is generally greater among boys than girls in most countries.1 Previous studies have shown that sex may be related to body weight and body composition patterns, with girls showing greater concerns for body image and a greater tendency to engage in weight loss behaviors to try to reach a normal weight,27,28 which could  (at least partially) explain our findings. In addition, sociocultural factors, such as social pressure and beauty ideals, may lead girls to be more conscious of their body image and exhibit behaviors related to weight loss.29 However, it is important to note that the prevalence of obesity varies according to other sociodemographic factors (i.e., age, race/ethnicity, or socioeconomic status).

Additionally, adolescents (aged 12 to 17 years) were less likely to have obesity than children (aged 5 to 11 years). These results were also observed in the analyses stratified by sex. A previous systematic review by Hajri et al.,4 which reported a slightly greater prevalence of obesity in children (10.7%) than in adolescents (10.5%) in Ecuador. However, other studies in other countries have reported a greater prevalence of obesity in adolescents than in children. For instance, one study in the United States reported that the prevalence of obesity among adolescents (aged 12 to 19 years; 20.6%) was greater than that among school-aged children (aged 6 to 11 years; 18.4%). Similarly, another study carried out in China revealed a greater prevalence of obesity in children (aged 7 to 12 years; 20.3%) than in adolescents (aged 13 to 17 years; 9.6%).30 During adolescence, there is an increased emphasis on matters related to one’s appearance, body weight, and various psychological aspects of development,31 which can explain these results. Another possible reason is that adolescents may have a better understanding of the consequences of unhealthy lifestyles, leading them to make more informed choices about their diet and physical activity compared to children.32

Furthermore, our results revealed an inverse relationship between the wealth family index and the prevalence of obesity. This result is in line with a previous study conducted by Abril et al.33 in children aged 6 to 9 years from Cuenca (Ecuador). In addition, a systematic review showed that European children whose parents were of greater socioeconomic status had a lower likelihood of having overweight or obesity.34 Similarly, Kim et al.35 reported in their longitudinal study in the United States that children from families with low incomes were more likely to have obesity than their counterpart children from families with high incomes were. Furthermore, another prospective cohort study by Wang et al.36 reported that poverty status was found to be the strongest predictor of obesity over time in youth from United States. Interestingly, a review by Vazquez and Cubbin12 outlined a clear pattern of an inverse relationship between socioeconomic status and childhood obesity in high-income countries.12 However, these same authors reported a disproportionate representation of research on the relationship between socioeconomic status and obesity in more affluent countries and, given the differential association between socioeconomic status and obesity-related outcomes in LMICs.12 In this sense, this study contributes to reducing the knowledge gap between studies conducted in high-income countries and those conducted in LMICs (i.e., Ecuador).

A higher education level of the breadwinner (i.e., middle/high school or higher) was also related to a lower probability of having obesity. This result is in line with the literature indicating that children of parents with higher education levels are less likely to have obesity.37 In this sense, for children with a low family income, children whose parents had less education were more likely to be in the trajectory of the obesity group than their counterparts were.35 Higher education levels are associated with healthier and more diverse diets, marked by increased consumption of fibers, fruits, vegetables, and fish products, whereas lower educational attainment tends to be associated with diets high in carbohydrates, sweets, and red meats, coupled with higher energy intake and larger portion sizes,38 which could be related to obesity among children and adolescents.39 Another possible reason is that education level may be a factor leading to greater leisure-time physical activity,40 which has been related to lower odds of having obesity.13,39,41,42 These findings are also in line with the results observed for the wealth family index, which is closely related to education level. In this sense, a study reported that the association between fathers’ and mothers’ education levels and obesity is moderated by household wealth.43 This could explain, at least in part, why higher levels of both factors were associated with a lower probability of obesity in Ecuadorian children and adolescents.

Another interesting finding was that participants from the coast and insular region (i.e., Islas Galápagos) were more likely to have obesity than their counterparts from the highlands. Despite the variability that exists between the different regions of the countries, this result is in line with the literature that points to differences depending on the region where children and adolescents live.44,45 One possible explanation is that the coast and insular region may have different dietary patterns than the highlands. Access to different types of food, availability of fresh produce, and cultural eating habits can vary between regions and influence the nutritional choices of individuals.46 Furthermore, sociocultural factors, including cultural norms and attitudes toward body image, physical activity, and diet, can vary across regions (i.e., the coast or insular region versus the highlands). These factors could impact lifestyle choices and contribute to disparities in obesity prevalence.47

Importantly, a greater number of days spent in physical activity was related to a lower probability of having obesity. This finding is in line with the scientific literature indicating the benefits of engaging in sufficient physical activity on obesity-related indicators.13,39,41,42 For instance, a systematic review with a meta-analysis by Poorolajal et al.39 with 1,636,049 children and adolescents reported lower odds of having obesity in those with sufficient physical activity. Similarly, García-Hermoso et al.42 reported that adolescents from the United States who met physical activity recommendations (especially in combination with meeting muscle‐strengthening activity recommendations) were less likely to have obesity. In addition, the low prevalence of meeting physical activity recommendations identified in this study in Ecuadorian children and adolescents is in line with the findings of previous studies,48,49 in Latin America, and in Ecuador.50 Given the low prevalence of physical activity in Ecuadorian children and adolescents, as well as its potential role in the prevention of childhood and adolescent obesity, initiatives to increase both the level of physical activity and equal opportunities for its practice in this age group are necessary.20

This study also revealed lower odds of having obesity in Ecuadorian children and adolescents who consume vegetables daily, which agrees with the findings of the scientific literature.16,51,52,53 For instance, a systematic review of cohort studies revealed that increasing vegetable intake reduces the risk of weight gain, overweight or obesity (in adults).53 More specifically, Ma et al.52 reported that greater vegetable consumption is related to a lower risk of cardiometabolic risk clusters (including obesity) in Chinese children and adolescents. Supporting this notion, the World Health Organization states that, when consumed as part of a healthy diet, vegetables (and fruits) may help prevent weight gain and reduce the risk of obesity among children and adolescents for various reasons.54 First, vegetables have a low caloric content and high fiber content, aiding in weight management by creating a sense of fullness and decreasing overall energy intake. Second, their abundance of essential nutrients can contribute to overall well-being and growth, potentially lowering the likelihood of complications associated with obesity. Third, when integrated into a nutritious diet that is low in fats, sugars, and salt, vegetables can assist in averting weight gain and diminishing the risk of obesity (among other noncommunicable diseases).

This study has several limitations. First, given the cross-sectional design of the study, we are not able to determine neither a cause‒effect relationship between the variables examined nor the direction of their association. Therefore, more longitudinal and experimental studies should be conducted to determine these relationships. Second, the questions for data collection in the ENSANUT-2018 were generally brief (intended to reduce the question burden on participants) and did not provide in-depth information to better understand the study findings. A more detailed measure would provide additional information for each item, as well as information on other aspects related to sociodemographic and lifestyle variables. Third, lifestyle data may lead to differential bias due to recall and information bias, social desirability bias, or underestimation/overestimation by parents/guardians or adolescents. Fourth, although we included relevant obesity-related factors, including sociodemographic factors (age, sex, race/ethnicity, wealth index, educational level, area of residence, region) and lifestyle variables (eating habits, physical activity, physical education, tooth brushing), it is still possible that other factors were involved. Conversely, this study has several strengths. The main strength of this study is the use of a nationwide and representative sample of children and adolescents from Ecuador, which provides external validity to the results, increasing the applicability and representativeness of the real-world scenarios. Furthermore, to our knowledge, this is the first study to examine sociodemographic and lifestyle variables related to obesity in a nationally representative sample of Ecuadorian children and adolescents (aged 5 to 17 years).

In conclusion, the high prevalence of obesity in Ecuadorian children and adolescents is a public health concern. Inequalities in sociodemographic factors (i.e., age, sex, wealth, educational level of the main breadwinner, and region), as well as in lifestyle factors (i.e., physical activity, vegetable consumption), seem to play a crucial role in the prevalence of obesity. These results highlight the need to consider sociodemographic and lifestyle factors in the prevention and management of obesity in Ecuador. Policies need to be implemented that address inequalities in obesity prevention and control, especially for younger children, boys, those from poorer families, those with a breadwinner with low educational level, and  for those living on the coast or in the insular region. These measures may involve advocating for the affordability and accessibility of vegetables and establishing secure and convenient areas for engaging in physical activities.