Overweight and obesity trends in school children
Obesity is now established to have reached epidemic levels in developing countries [54] unlike previous reports that showed it was restricted to developed countries [58]. Different studies in Africa have shown an upward trend in obesity from the lowest reported at 5% to the highest at above 30% among school children across the period of 10 years which this review considered. This trend is almost similar to what was reported in developed countries and some other developing countries in the global south. For instance, in Latin America more than 20% of school children were obese [66] and in San Diego the prevalence of overweight and obesity in children was 26. 6% [44]. Similarly, high prevalence of overweight and obesity (39.7%) were found in Mexican school children [67] while 31% of Canadian [68], 36.6% of Saudi Arabian [69], and 32% of American [45] school children were reported to be overweight and obese. Since 2013, published articles showed increased figures of overweight and obesity compared to articles published before 2013 [3, 12, 51]. However, data on overweight and obesity are complex and confusing due to different contexts and age group under investigation. Some evidence showed that cultural and environmental factors may explain variation in obesity data among study subjects [22, 51, 58]. Difference in socio-economic status also contributed to these variations, as children from higher SES are reported to be more obese than children from lower SES [8, 11, 51, 70]. Children from urban areas were found to be more obese than children from rural areas in Tanzania, with Tluway et al., (59) reporting a lower prevalence of overweight and obesity (9.2%) in rural adolescents of Tanzania compared to urban children at 22.6% [58]. Similarly, Zhang et al. [71] found an increased risk of overweight and obesity in urban Chinese school children, which may be caused by difference in lifestyle behaviors between rural and urban settings. Generally, most urban populations have sedentary lifestyles and increased consumption of high energy dense foods [55, 72]. Many studies across countries reported higher prevalence of overweight in girls compared to boys [6, 11, 12, 14, 50, 52, 53, 55, 58]. This may be attributed to differences in gender roles where boys participate more in higher energy utilization activities than girls [51]. Early onset of menarche in girls is associated with an increase in body fat and body weight [59]. In addition, children below 10 years were more likely to be obese than children/adolescent above 10 years [5, 54]
Home and school food environment
There is limited information on the influence of home and school environment on school children’s food choice and obesity linkages. However, reviewed studies have demonstrated that obesity is a significant health problem and provide direction for evidence-based strategies and interventions.
Apart from biophysical factors (i.e., genes, age, gender), the ecological perspective states that the physical environment has a direct link to obesity due its influence on food choices [2]. Studies from South Africa reported that school children buy and consume unhealthy foods near school premises [37], which calls for creating enabling healthy food environment. Evidence from Brazil showed that public school students are exposed to food stores which provide fewer natural foods but rather energy dense-foods [66]. A mini-review on Indian school children’s food environment also reported high access of school children to low cost energy dense foods like refined carbohydrates, saturated fats, and sugar sweetened beverages [27].A systematic review reported that fast food shops and cafeteria located in school environments in developing countries give students access to high caloric, nutritionally inadequate foods [73]. Availability of empty-calorie foods at school and home have direct links to poor food choice and consumption [2]. Conversely, [69] found a positive association between increased intakes of sugar-sweetened carbonated beverages with increase in BMI, contributing to obesity-related outcomes in Saudi Arabian school children. This finding is similar to a study conducted in San Diego [44] where a positive association was found between unhealthy foods available at home and high intake of caloric beverage while the intake of fruits and vegetables were low. However, a study conducted in the Southern Appalachia found availability of high fats foods and sweets in the home environment have less effect on child’s overweight status if there is strict parental control [45], which was also shown to influence healthy food choices during adolescence and adulthood [29]. This finding is similar to a study among Irish children which revealed that parents had the most significant control of what a child chooses to eat [30]. Findings from other review articles found that parents have more influence to determine food amount/portion size to be offered to children, however, decision, motivation and parental feeding goals are not well understood [74]. Presence of parents at home and their involvement in feeding practices apart from influencing role modeling, they also shape positive behavior change and modification of available foods and soft drinks in the home environment [75].
Strategies to creating enabling healthful food environment
- Conducting informative research
Effective implementation of optimal intervention strategies to prevent obesity in the African context needs sufficient evidence on current and periodic trends of obesity across countries [76]. Knowledge about food choice and dietary habits data among African school children is inadequate, therefore, more consumer research on school and home food environment is required. Studies in developing countries need to examine the role of local or informal food vendors and other sources of food like home production and food donations on food choice [24]. There is a need to focus on the penetration of supermarkets which offer highly processed food varieties [24]. Nevertheless, before launching school-based interventions in low and middle-income countries, we need to establish culturally based evidence. This is because of differences in values, norms, customs, and environmental influences on food choices for children and the existing models from developed countries may not work in the African context [77]. Barriers and facilitators influencing healthy eating behaviors in the home and school environment need to be thoroughly investigated as little research exist in this area. Context specific school-based interventions, if implemented effectively, can improve the nutritional status of school children.
- Designing social ecological frameworks
The social ecological perspective describes relationships between an individual and environment positing that individual behavior emerges from the interplay of multiple factors between the two entities [78]. The social ecological framework considers five levels of influence: Individual ((knowledge, attitude, and self-concept); Interpersonal (family, peers, friends, social networks); Community (relationships between organizations); Organizational (organizations and social institutions); and Policy/enabling environment (national, state, local). At the individual level, school children need to receive nutrition education to equip them with appropriate knowledge to make informed healthy food choices, and change their attitudes and skills to build self-efficacy [63, 79]. At the interpersonal/family/home level, training of parents and modification of home environment is required. It is also imperative to create awareness through health promotion campaigns targeting parents, households, and communities on health diet and dietary diversity. Dietary diversity should promote consumption of nutrient-dense culturally acceptable foods and minimize consumption of processed foods [80]. Parents have the role to model healthy eating habits and food choices, because they impact what their child consume. Parents should be well informed on the outcome of poor dietary habits of their children; therefore, they should be motivated to set a good example for their children. [74]. At the organization/school level, teachers are capacitated to deliver nutrition education and communication messages to pupils. Promotion/modification of school food policy/environment and creating resources for physical activity can easily be designed and implemented at school level. National and local levels are obliged to set policies and laws that will promote the creation of healthful food enabling environment.
- Multisectoral partnership/coordination
Prevention and/or management of overweight and obesity in children is a shared responsibility between different sectors. No single sector will address this complex, multi-faceted problem. African member states (i.e., governments) should be willing to take responsibilities through preparation and enhancement policies across all sectors [10]. The health sector needs to initiate, implement, and innovate primary and secondary overweight/obesity preventive measures. The education sector needs to integrate and implement nutrition related courses in primary school curriculum [81], with content delivery predicated on the building of teachers’ capacities, thereby equipping them to confidently and consistently deliver nutrition education to children. The agriculture sector needs to emphasize on production of local nutrient-dense food crops at an affordable cost together with periodic revision of import trade policies [10]. Food regulatory bodies are tasked to set and enforce import requirements and regulations to ensure that imported foods meet agreed quality standards [82]. In addition, the business sector (food and beverage industry) need to focus on healthy product development, whereby they reformulate nutrient dense food categories to deliver better diets for all. Due to industrial development and economic changes many people have shifted their food habits leading to a tendency to purchase and consume more processed, packed foods and drinks, while minimizing intake of fruits, vegetables, whole cereals and legumes [41], contributing increased intake of high energy giving foods. Therefore, this sector needs high level of commitment in addressing global and regional nutritional challenges by manufacturing healthy products that are affordable and available to all groups of consumers.
- Social behavior change communication
One of the most promising strategies to prevent childhood obesity is social behavior change communications. This strategy includes individual counselling, mass media campaigns, and education sessions. If these are targeted to relevant audiences, like school children, schools, non-governmental organization, and decision makers, the expected outcomes may be achieved [47]. An example of this approach is reflected in Tanzania’s national nutrition social behavior change communication (SBCC) strategy which aims at raising awareness through an increase in knowledge, attitude, and skill training. It also aims at creating quality nutrition services that will favor demand of consumers, other beneficiaries and increase access to quality communication materials, SBCC guidelines, protocols, and other tools to district level [83]. SBCC needs to be developed, pre-tested, and disseminated to target population. A review of literature in developing countries showed success on integrating social behavior change communication interventions with nutritional specific programs [84]. For example, a study conducted in Malawi used social behavior change communication messages in a supplementary feeding program which resulted in knowledge and practices improvement among caregivers in the intervention groups compared to control group [85].
Limitations of this review
This review is restricted to school and home physical food environment, specifically focusing on availability and accessibility to foods. Other components, like individual, socio-cultural factors, presence of electronic devices, and physical inactivity/sedentary behaviors, were not considered. However, they are all factors which potentially contribute to increased prevalence of overweight and obesity in school children. Again, the review focused mainly on overweight and obesity among school children, while the double burden malnutrition (under and over nutrition) is evident in African countries. This review focuses on a topic which, in most cases, receives less attention in nutrition research and interventions than the undernutrition profile.