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Nutrition Interventions To Decrease The Prevalence Of Childhood Overweight And Obesity

Posted:  Tuesday, September 02, 2014

(Prepared by Cecile van Niekerk under supervision of Gerda Gericke and Zelda White)

There are many interventions for the prevention of childhood overweight and obesity. Obesity is a disease in its own right and needs intervention even if no co-morbidities are present. There are three levels of prevention, namely universal prevention that focuses on the general population, selective prevention that focuses on high risk population groups, and targeted prevention that focuses on individuals who are diagnosed as being overweight.

A change of lifestyle is the most important issue to address when aiming to prevent childhood obesity. Control of body weight is centre thereof and should be composed of reasonable weight goals with a healthy eating component, physical activity component as well as psychological and behavioural component. Each treatment plan should be individualised, realistic, and maintainable and should contribute to general well-being.

The WHO Expert Consultation on Obesity identified public obesity prevention programmes as immediate action priorities. Such programmes are based upon principles where the intervention is focused on education, and mainly addresses environmental and social factors to promote and support behaviour change. It also includes education on increased physical activity, integration of new initiatives within existing programmes which are all based on scientific evidence and is properly monitored, evaluated and documented. To ensure sustainability of prevention and primary health care programmes, programmes must ensure an improvement in dietary intake, physical activity and obesity levels over time. This requires support from political parties as well as inter sectoral collaboration and community participation which are all essential factors for success.

The mode of delivery of prevention programmes should also be considered. Possibilities include self-initiated group settings as seen with self-help programmes, also non-clinical programmes provided by trained professionals to groups or individuals, and clinical programmes provided by registered health care professionals for other professionals, groups or individuals.

Setting for health education
The school is the ideal environment for the delivery of interventions for childhood obesity because schools are already established as settings for health promotion activities. A large proportion of the population is represented by school-going children and they are available over prolonged periods of time in a setting where education and learning is the norm. There is also some evidence that family involvement of health promotion programmes can positively influence the wider community. The education and learning performance of school children may be enhanced when their general health is improved through health education.

From the PEACH RCT conducted with preadolescent obese children it was seen that the most effective weight management strategies were those approaches that focused on the parents to take sole responsibility for implementing the strategies. A relative weight loss of 10% was seen and maintained for two years from baseline. Therefore including the parents in weight management strategies may be an effective secondary obesity-prevention strategy. Furthermore, children are highly dependent on their parents who control to a great extent the food served at home. When the correct nutritious food is in the home, environmental cues to eat high-fat, energy-dense foods are reduced, and following the healthy dietary regimen is enhanced. Family members can serve as good role models for appropriate eating and encourage healthful behaviours in the child. Children also frequently mimic their parents’ food habits. Parents should therefore be supportive of their children and role models themselves. Parents should not nag or criticise about food and weight issues, and should rather use positive reinforcement and praise them when correct dietary behaviours are observed.

Behavioural focused education
Behaviourally focused nutrition education is appropriate to use, including cognitive learning (how to select a healthful diet), affective teaching (address motivation for change) with behavioural components (selecting new food choices). Studies indicate that interventions that focus on specific behaviour changes result in more changes than a more general nutrition education approach. The Social Learning Theory (SLT) emphasises the interaction between individual, behavioural and environmental factors and is popular for school-based interventions that promote changes in physical activity and healthy eating. Most of the nutrition education programmes in the studies of best clinical outcomes, that resulted in behaviour change, used teaching strategies based on the SLT which suggests that most health behaviours are learned in a social context. In such programmes increasing knowledge should only be one of many aims. Nutrition knowledge alone does not enable a young person to adopt healthy eating behaviours. Although the association between nutrition knowledge and behaviour where found to be weak it has been reported that nutrition knowledge is remains vital for success. Therefore behaviourally-centred approaches, for example skill building, goal setting and efficacy-enhancing experiences are needed. Behavioural changes may not be upheld if the school environment does not support the changes and the home environment does not reinforce the intentions. In the earlier grades family-based programmes were found to be more effective than for high school students.

Educational strategies that actively involve the learners are preferred and passive techniques are undesirable. Curiosity can be stimulated with a fantasy of a play, game or puzzle as well as music, bright colours or visual effects. To stimulate cognitive curiosity varying levels of difficulty, competition, nutrition bingo or scavenger hunts can be used. Topics considered essential for school children may include the food guide pyramid, benefits of healthy eating, healthful food choices and preparation of meals and snacks, eating a variety of foods, eating more fruits, vegetables, grains and calcium-rich foods, eating less saturated fat, fatty foods, sugar and salt, read and interpret food labels, balance food intake with physical activity, accepting body size differences, and food safety practices.

In one study (MARG intervention study) the education intervention for children aged eight to ten years had lectures conducted in easily comprehensible power-point presentations with cartoon characters, pictures and interesting quotations. The lectures were followed by interactive discussions where the dietitian addressed nutrition-related questions from learners and their parents. An easily understood, attractive information leaflet was distributed as take-home material to reinforce the lessons received through the lectures and group discussions.

Each lesson of the PATHWAYS curricula included three to four classroom activities which consisted of two 45min sessions per week for a total of 12 weeks. The curriculum was developed by a curriculum working group which comprised of a multidisciplinary team from the representing universities, American Indian nations and teachers. The PATHWAYS classroom curriculum included culturally appropriate lessons which consisted of tribal knowledge, maps of the Pathway Nations, and American Indian stories. The classroom and take home activities where developed to promote healthy eating behaviour and improve physical activity levels. An environment of enhanced learner interest was established by audiotaped American Indian flute music at the start of each lesson. The focus of the lessons was the importance of a healthy and balanced life and not obesity prevention as such. Some of the Pathway activities helped the learners to set personal goals, to prepare healthy snacks, to taste-test new foods, and ultimately to make healthy food choices and being physically active by playing cultural games during exercise breaks.

Best clinical outcomes of interventions for the prevention of childhood overweight and obesity
Evidence tables on interventions to improve diet and physical activity were compiled for the WHO. “Interventions on diet and physical activity: What Works” addresses the responsibility of the WHO and world stake holders to take action to improve dietary intake and to increase physical activity. Three hundred and ninety five peer reviewed studies met the inclusion criteria, which was then summarized into a table, presented into eight categories namely policy and environment, mass media, school setting, the workplace, the community, primary health care, older adults and religious settings. Information was used on the applicable parts of the intervention, on three primary outcome measures, and on criteria that may be useful for policy makers seeking a diet and physical activity intervention.

Best practice is defined by the WHO as, “most likely to be effective and refers to studies/interventions that have typically been based on formative assessment with an experimental design or large study sample and with significant and substantive effects on specified outcome variables.” Best practice studies can be applied to a wider variety of situations and demonstrate feasibility and sustainability in their specific setting.

Numerous studies have been classified as best practise regarding behaviour including PATHWAYS, CATCH, High-5, KYBP, Eat well and keep moving, Healthy Start and Squire’s test. The PATHWAYS intervention placed a strong emphasis on cultural identity and was based on social learning theory with a very comprehensive programme involving teachers, parents, children and the school canteen. CATCH focused on food service personnel and managers to lower consumption of total fat, saturated fat and sodium in school meals with very successful outcome where even after five years 50% of the intervention schools still complied with the low fat objectives compared with only 10% of control schools. The High-5 project were very similar to the PATHWAYS with a focus on parental involvement, the school curriculum as well as a food service component and found significant increases in consumption of fruit, vegetables, fibre, beta-carotene and vitamin C. Squire’s test was an interactive game targeted at primary school children where they found that children participating in this multimedia game significantly increased their vegetable and fruit consumption with one serving daily above the control group’s intake.

In conclusion, to successfully change earing behaviour, interventions must aim to modify the child’s eating behaviour in regard to individual, behavioural and environmental factors. School interventions can have best practice behavioural and/ or psychosocial outcomes if a nutrition-based curriculum is offered at the school by trained teachers, and also includes a physical activity programme/component as well as a family/parental component.


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