Childhood obesity: Desk research
Summary of findings
Whilst certain genes can pre-dispose children to obesity, in a genetically stable population, the recent increase in obesity prevalence in children is a result of an increasing proportion of children who consume a greater amount of energy through diet than they expend through physical activity. Key causes of childhood obesity are:
- High consumption of foods high in fat and sugar
- Disproportionate consumption of convenience foods
- A consensus seems to be emerging that high consumption of foods that are “energy-dense” (either in fat or high glycaemic carbohydrates) contributes to obesity because both of these types of nutrient can reduce appetite control and in themselves tip the energy balance.
- Parents giving in to child’s preference for foods high in fat and sugar due to lack of time, the inability of some parents to conceive of a healthy menu that is not austere or bland, the low status of vegetables as a food, and the view that certain food types are “children’s foods”.
- The epidemiological data does not unanimously agree that a lack of physical activity causes childhood obesity, but the balance of evidence at the moment suggests that it does. However, there is much more evidence that excessive TV watching leads to obesity in children.
- Data does not exist showing us the physical activity characteristics of obese children in the UK relative to non-obese children. Furthermore, trend data on levels of physical activity in the UK as a whole are patchy and do not correlate with the recent rise in obesity.
- However, there are clear barriers to promoting childhood physical activity, both in the form of lack of resources in schools and parental attitudes.
- The Health Survey for England shows that 19.8% of children living in households where both parents are either overweight or obese were themselves obese compared with 6.7% of children living in households where neither parents were overweight or obese.
The Health Survey for England also suggests that the drivers of childhood obesity are stronger amongst socio-economic groups. For example:
- Children in the most (top quintile) deprived areas are more likely to be obese (16.4%) than those in the least (bottom quintile) deprived areas (11.2%).
- Obesity prevalence is lowest in Yorkshire and the Humber (11.4%) and the South East (13.4%) and highest in the North East (18.3%) and London (18.2%). This may reflect socio-economic patterns across England, or regional diet differences.
Ethnicity, age and gender
The Health Survey for England also shows that:
- Ethnicity: Black African, Black Caribbean and Pakistani girls are at increased risk of obesity. Indian and Pakistani boys are more likely to be overweight than the rest of the population.
- Gender: Boys were slightly more likely to be obese than girls (14.9% compared to 12.5%).
- Age: Children aged 8 to 10 were more likely to be obese than children aged 2 to 3 (16.5% compared to 11.5%).
The government already has a number of strategies to tackle some of the drivers of obesity, mostly through schools. These include PESSCL (school PE and sport), the 5 A Day campaign (promoting fruit and vegetables), Fruit in Schools, Safer Routes to Schools (to encourage walking to schools), Extended Schools (including after-school sport clubs), school breakfast clubs and forthcoming reforms to school meals. Most of these are very much concerned with removing practical barriers to healthy eating and physical activity. The analysis here, however, suggests that shifting parental attitudes is also key. Any strategy that attempts to stem the rise in childhood obesity should therefore explore ways to:
- Show time-pressured parents how to provide children with a healthy diet, especially fruit and vegetables.
- Encourage parents to determine what their children eat, rather than allowing their children to dictate their diets.
- Recommend that parents limit the amount of time that children spend on sedentary activities.
- Show that providing your child with a healthy diet and the opportunity to do plenty of physical activity is as important as meeting their immediate material and emotional needs.
To inform the selection of the most effective interventions to halt the growth in obesity in children, the DH commissioned this research looking into the evidence for the causes of obesity in this age group.
In particular, the DH wish to understand:
- Current hypotheses on the causes of obesity amongst children under the age of 11
- The evidence for the causes of obesity in this age group
- The strength of different factors in causing obesity, and consequently, those interventions that would be most appropriate for tackling the causes of obesity
- The characteristics of those children most at risk of becoming obese
This report was commissioned to inform the strategy to halt the growth in obesity amongst under 11 year olds.
This was desk research which reviewed a large number of different studies. The report mentions that Black African, Black Caribbean and Pakistani girls are at increased risk of obesity. Indian and Pakistani boys are more likely to be overweight than the rest of the population.
This was desk research which reviewed a large number of different studies. Report mentions that the prevalence of obesity amongst children aged 2 to 10 rose from 9.9% to 13.7% from 1995 to 2003. Moreover children aged 8 to 10 were more likely to be obese than children aged 2 to 3 (16.5% compared to 11.5%).
Data collection methodology
Other data collection methodology
A set of initial hypotheses were suggested by the researcher for the causes of obesity at the start of this research project. These were then re-fined at a kick-off workshop on 4 November 2005. The evidence to prove or disprove these hypotheses was then reviewed. At the start of sections 4 and 5 on diet and physical activity, summaries are provided of the hypotheses tested and the outcome. To ensure that all the evidence was included, a trawl of sources was undertaken. Academic research was identified through specialist search engines, including Infotrieve (which includes MedLine) and Highbeam. Collections of academic essays in books by the British Nutrition Foundation1 and Walter Burniat2 were also used. In addition, a considerable body of evidence from public sector organisations was consulted, in particular from the Food Standards Agency, the Department of Health and Ofcom.
This was desk research which reviewed a large number of different studies.
Wide range of reports analysed with much national quantitative date presented
Most literature reviewed dates back over the last 10 years, a small number of references date back to 70s/80s.
Agree to publish
Low/ moderate – see methodological comments below.