Estimating the changes in energy flux that characterize the rise in obesity prevalence

Background: The daily energy imbalance gap associated with the current population weight gain in the obesity epidemic is relatively small. However, the substantially higher body weights of populations that have accumulated over several years are associated with a substantially higher total energy expenditure (TEE) and total energy intake (TEI), or energy flux (EnFlux = TEE = TEI).
Objective: The objective was to develop an equation relating EnFlux to body weight in adults for estimating the rise in EnFlux associated with the obesity epidemic.
Design: Multicenter, cross-sectional data for TEE from doubly labeled water studies in 1399 adults aged 5.9 ± 18.8 y (mean ± SD) were analyzed in linear regression models with natural log (ln) weight as the dependent variable and ln EnFlux as the independent variable, adjusted for height, age, and sex. These equations were compared with those for children and applied to population trends in weight gain.
Results: ln EnFlux was positively related to ln weight (β = 0.71; 95% CI: 0.66, 0.76; R2 = 0.52), adjusted for height, age, and sex. This slope was significantly steeper than that previously described for children (β = 0.45; 95% CI: 0.38, 0.51).
Conclusions: This relation suggests that substantial increases in TEI have driven the increases in body weight over the past 3 decades. Adults have a higher proportional weight gain than children for the same proportional increase in energy intake, mostly because of a higher fat content of the weight being gained. The obesity epidemic will not be reversed without large reductions in energy intake, increases in physical activity, or both.

Dietary patterns of adolescents and risk of obesity and hypertension

Increasingly, measures of dietary patterns have been used to capture the complex nature of dietary intake and investigate its association with health. Certain dietary patterns may be important in the prevention of chronic disease; however, there are few investigations in adolescents. The aim of this study was to describe the dietary patterns of adolescents and their associations with sociodemographic factors, nutrient intakes, and behavioral and health outcomes. Analysis was conducted using data collected in the 1995 Australian National Nutrition Survey of participants aged 12–18 y who completed a 108-item FFQ (n = 764). Dietary patterns were identified using factor analysis and associations with sociodemographic factors and behavioral and health outcomes investigated. Factor analysis revealed 3 dietary patterns labeled a fruit, salad, cereals, and fish pattern; a high fat and sugar pattern; and a vegetables pattern, which explained 11.9, 5.9, and 3.9% of the variation in food intakes, respectively. The high fat and sugar pattern was positively associated with being male (P < 0.001), the vegetables pattern was positively associated with rural region of residence (P = 0.004), and the fruit, salad, cereals, and fish pattern was inversely associated with age (P = 0.03). Dietary patterns were not associated with socioeconomic indicators. The fruit, salad, cereals, and fish pattern was inversely associated with diastolic blood pressure (P = 0.0025) after adjustment for age, sex, and physical activity in adolescents ≥16 y. This study suggests that specific dietary patterns are already evident in adolescence and a dietary pattern rich in fruit, salad, cereals, and fish pattern may be associated with diastolic blood pressure in older adolescents.

Obesity policy action framework and analysis grids for a comprehensive policy approach to reducing obesity

A comprehensive policy approach is needed to control the growing obesity epidemic. This paper proposes the Obesity Policy Action (OPA) framework, modified from the World Health Organization framework for the implementation of the Global Strategy on Diet, Physical Activity and Health, to provide specific guidance for governments to systematically identify areas for obesity policy action. The proposed framework incorporates three different public health approaches to addressing obesity: (i) 'upstream' policies influence either the broad social and economic conditions of society (e.g. taxation, education, social security) or the food and physical activity environments to make healthy eating and physical activity choices easier; (ii) 'midstream' policies are aimed at directly influencing population behaviours; and (iii) 'downstream' policies support health services and clinical interventions. A set of grids for analysing potential policies to support obesity prevention and management is presented. The general pattern that emerges from populating the analysis grids as they relate to the Australian context is that all sectors and levels of government, non-governmental organizations and private businesses have multiple opportunities to contribute to reducing obesity. The proposed framework and analysis grids provide a comprehensive approach to mapping the policy environment related to obesity, and a tool for identifying policy gaps, barriers and opportunities.

Maintenance of traditional cultural orientation is associated with lower rates of obesity and sedentary behaviours among African migrant children to Australia

Background: Migrants from developing to developed countries rapidly develop more obesity than the host population. While the effects of socio-economic status on obesity are well established, the influence of cultural factors, including acculturation, is not known.

Objective: To examine the association between acculturation and obesity and its risk factors among African migrant children in Australia.

Design and participants: A cross-sectional study using a non-probability sample of 3- to 12-year-old sub-Saharan African migrant children. A bidimensional model of strength of affiliation with African and Australian cultures was used to divide the sample into four cultural orientations: traditional (African), assimilated (Australian), integrated (both) and marginalized (neither).

Main outcome measures: Body mass index (BMI), leisure-time physical activity (PA) and sedentary behaviours (SBs) and energy density of food.

Results: In all, 18.4% (95% confidence interval (CI): 14–23%) were overweight and 8.6% (95% CI: 6–12%) were obese. After adjustment for confounders, integrated (ß=1.1; P<0.05) and marginalized ß(=1.4; P<0.01) children had higher BMI than traditional children. However, integrated children had significantly higher time engaged in both PA (ß=46.9, P<0.01) and SBs (ß=43.0, P<0.05) than their traditional counterparts. In comparison with traditional children, assimilated children were more sedentary (ß=57.5, P<0.01) while marginalization was associated with increased consumption of energy-dense foods (ß=42.0, P<0.05).

Conclusions: Maintenance of traditional orientation was associated with lower rates of obesity and SBs. Health promotion programs and frameworks need to be rooted in traditional values and habits to maintain and reinforce traditional dietary and PA habits, as well as identify the marginalized clusters and address their needs.

A systematic policy approach to changing the food system and physical activity environments to prevent obesity

As obesity prevention becomes an increasing health priority in many countries, including Australia
and New Zealand, the challenge that governments are now facing is how to adopt a systematic
policy approach to increase healthy eating and regular physical activity. This article sets out a
structure for systematically identifying areas for obesity prevention policy action across the food
system and full range of physical activity environments. Areas amenable to policy intervention can
be systematically identified by considering policy opportunities for each level of governance (local,
state, national, international and organisational) in each sector of the food system (primary
production, food processing, distribution, marketing, retail, catering and food service) and each
sector that influences physical activity environments (infrastructure and planning, education,
employment, transport, sport and recreation). Analysis grids are used to illustrate, in a structured
fashion, the broad array of areas amenable to legal and regulatory intervention across all levels of
governance and all relevant sectors. In the Australian context, potential regulatory policy
intervention areas are widespread throughout the food system, e.g., land-use zoning (primary
production within local government), food safety (food processing within state government), food
labelling (retail within national government). Policy areas for influencing physical activity are
predominantly local and state government responsibilities including, for example, walking and
cycling environments (infrastructure and planning sector) and physical activity education in schools
(education sector). The analysis structure presented in this article provides a tool to systematically
identify policy gaps, barriers and opportunities for obesity prevention, as part of the process of
developing and implementing a comprehensive obesity prevention strategy. It also serves to
highlight the need for a coordinated approach to policy development and implementation across
all levels of government in order to ensure complementary policy action.

Preventing childhood obesity : the sentinel site for obesity prevention in Victoria, Australia

In spite of greater awareness of the need for action to reduce obesity, the evidence on sustainable community approaches to prevent childhood and adolescent obesity is surprisingly sparse. This paper describes the design and methodological components of the Sentinel Site for Obesity Prevention, a demonstration site in the Barwon-South West region of Victoria, Australia, that aims to build the programs, skills and evidence necessary to attenuate and eventually reverse the obesity epidemic in children and adolescents.

The Sentinel Site for Obesity Prevention is based on a partnership between the region's university (Deakin University) and its health, education and local government agencies. The three basic foundations of the Sentinel Site are: multi-strategy, multi-setting interventions; building community capacity; and undertaking program evaluations and population monitoring. Three intervention projects have been supported that cover different age groups (preschool: 2–5 years, primary school: 5–12 years, secondary school: 13–17 years), but that have many characteristics in common including: community participation and ownership of the project; an intervention duration of at least 3 years; and full evaluations with impact (behaviours) and outcome measures (anthropometry) compared with regionally representative comparison populations.

We recommend the Sentinel Site approach to others for successfully building evidence for childhood obesity prevention and stimulating action on reducing the epidemic.

Obesity prevention : the role of policies, laws and regulations

The commercial drivers of the obesity epidemic are so influential that obesity can be considered a robust sign of commercial success – consumers are buying more food, more cars and more energy-saving machines. It is unlikely that these powerful economic forces will change sufficiently in response to consumer desires to eat less and move more or corporate desires to be more socially responsible. When the free market creates substantial population detriments and health inequalities, government policies are needed to change the ground rules in favour of population benefits.
Concerted action is needed from governments in four broad areas: provide leadership to set the agenda and show the way; advocate for a multi-sector response and establish the mechanisms for all sectors to engage and enhance action; develop and implement policies (including laws and regulations) to create healthier food and activity environments, and; secure increased and continued funding to reduce obesogenic environments and promote healthy eating and physical activity.
Policies, laws and regulations are often needed to drive the environmental and social changes that, eventually, will have a sustainable impact on reducing obesity. An 'obesity impact assessment' on legislation such as public liability, urban planning, transport, food safety, agriculture, and trade may identify 'rules' which contribute to obesogenic environments. In other areas, such as marketing to children, school food, and taxes/levies, there may be opportunities for regulations to actively support obesity prevention. Legislation in other areas such as to reduce climate change may also contribute to obesity prevention ('stealth interventions'). A political willingness to use policy instruments to drive change will probably be an early hallmark of successful obesity prevention.

Brain neuropeptide Y and CCK and peripheral adipokine receptors : temporal response in obesity induced by palatable diet

Objective:
Palatable food disrupts normal appetite regulation, which may contribute to the etiology of obesity. Neuropeptide Y (NPY) and cholecystokinin play critical roles in the regulation of food intake and energy homeostasis, while adiponectin and carnitine palmitoyltransferase (CPT) are important for insulin sensitivity and fatty acid oxidation. This study examined the impact of short- and long-term consumption of palatable high-fat diet (HFD) on these critical metabolic regulators.

Methods:
Male C57BL/6 mice were exposed to laboratory chow (12% fat), or cafeteria-style palatable HFD (32% fat) for 2 or 10 weeks. Body weight and food intake were monitored throughout. Plasma leptin, hypothalamic NPY and cholecystokinin, and mRNA expression of leptin, adiponectin, their receptors and CPT-1, in fat and muscles were measured.

Results:
Caloric intake of the palatable HFD group was 2–3 times greater than control, resulting in a 37% higher body weight. Fat mass was already increased at 2 weeks; plasma leptin concentrations were 2.4 and 9 times higher than control at 2 and 10 weeks, respectively. Plasma adiponectin was increased at 10 weeks. Muscle adiponectin receptor 1 was increased at 2 weeks, while CPT-1 mRNA was markedly upregulated by HFD at both time points. Hypothalamic NPY and cholecystokinin content were significantly decreased at 10 weeks.

Conclusion:
Palatable HFD induced hyperphagia, fat accumulation, increased adiponectin, leptin and muscle fatty acid oxidation, and reduced hypothalamic NPY and cholecystokinin. Our data suggest that the adaptive changes in hypothalamic NPY and muscle fatty acid oxidation are insufficient to reverse the progress of obesity and metabolic consequences induced by a palatable HFD.

Weighing it up : thinking about the implications of school based obesity prevention initiatives

In this paper we explore the tensions that exist between two health promotion discourses prevalent in school based Health Education. We use one example from a widely used curriculum resource and one classroom episode to explore discourses related to obesity prevention, often described as an obesity epidemic by media and health professionals alike. Our argument is that these discourses work to produce the 'unhealthy other' that everyone is then in danger of becoming and in the process produce moral judgements and reinforce stereotypes about overweight and obese people. In so doing they run counter to health education and other discourses that seek to promote self-esteem and body acceptance in students no matter what their shape and size.

Double disadvantage : the influence of ethnicity over socioeconomic position on childhood overweight and obesity: findings from an inner urban population of primary school children

Objective: To examine the relationship between overweight/obesity in children, socioeconomic status and ethnicity/cultural background.

Design: Cross-sectional survey of children aged 4–13 years.

Setting: A total of 23 primary (elementary) schools in an inner urban municipality of Melbourne, Australia.

Participants: A total of 2685 children aged 4–13 years and their parents.

Main exposure measures: Ethnicity/cultural background – maternal region of birth; socioeconomic position (SEP) indicators – maternal and paternal educational attainment, family employment status, possession of a healthcare card, ability to buy food, indicator of disadvantage (Socioeconomic Index for Areas, SEIFA) score for school; parental weight status.

Main outcome measure: Prevalence of overweight/obesity.

Results: Prevalence of overweight/obesity approached 1 in 3 (31%) in this sample. Prevalence of overweight/obesity was greater for children of both North Africa and Middle Eastern background and children of Southern, South Eastern and Eastern European background compared with children of Australian background. This difference remained after adjusting for age, sex, height, clustering by school, SEP indicators and parental weight status; odds ratio, OR=1.57 (95% confidence interval, CI 1.12–2.19) and 1.88 (95%CI 1.24–2.85), respectively.

Conclusions: There is a clear independent effect of ethnicity above and beyond the effect of socioeconomic status on overweight and obesity in children. Further research is required to explore the mediators of this gradient.

Objectively measured sedentary time, physical activity, and metabolic risk the Australian diabetes, obesity and lifestyle tudy (AusDiab)

OBJECTIVE—We examined the associations of objectively measured sedentary time and physical activity with continuous indexes of metabolic risk in Australian adults without known diabetes.

RESEARCH DESIGN AND METHODS—An accelerometer was used to derive the percentage of monitoring time spent sedentary and in light-intensity and moderate-to-vigorous–intensity activity, as well as mean activity intensity, in 169 Australian Diabetes, Obesity and Lifestyle Study (AusDiab) participants (mean age 53.4 years). Associations with waist circumference, triglycerides, HDL cholesterol, resting blood pressure, fasting plasma glucose, and a clustered metabolic risk score were examined.

RESULTS—Independent of time spent in moderate-to-vigorous–intensity activity, there were significant associations of sedentary time, light-intensity time, and mean activity intensity with waist circumference and clustered metabolic risk. Independent of waist circumference, moderate-to-vigorous–intensity activity time was significantly beneficially associated with triglycerides.

CONCLUSIONS—These findings highlight the importance of decreasing sedentary time, as well as increasing time spent in physical activity, for metabolic health.

Joint associations of multiple leisure-time sedentary behaviours and physical activity with obesity in Australian adults

Background
Television viewing and physical inactivity are independently associated with risk of obesity. However, how the combination of multiple leisure-time sedentary behaviours (LTSB) and physical activity (LTPA) may contribute to the risk of obesity is not well understood. We examined the joint associations of multiple sedentary behaviours and physical activity with the odds of being overweight or obese.

Methods
A mail survey collected the following data from adults living in Adelaide, Australia (n = 2210): self-reported height, weight, six LTSB, LTPA and sociodemographic variables. Participants were categorised into four groups according to their level of LTSB (dichotomised into low and high levels around the median) and LTPA (sufficient: ≥ 2.5 hr/wk; insufficient: < 2.5 hr/wk). Logistic regression analysis examined the odds of being overweight or obese (body mass index ≥ 25 kg/m2) by the combined categories.

Results
The odds of being overweight or obese relative to the reference category (low sedentary behaviour time and sufficient physical activity) were: 1.54 (95% confidence interval [CI]: 1.20–1.98) for the combination of low sedentary behaviour time and insufficient physical activity; 1.55 (95% CI: 1.20–2.02) for the combination of high sedentary behaviour time and sufficient physical activity; and 2.26 (95% CI: 1.75–2.92) for the combination of high sedentary behaviour time and insufficient physical activity.

Conclusion
Those who spent more time in sedentary behaviours (but were sufficiently physically active) and those who were insufficiently active (but spent less time in sedentary behaviour) had a similar risk of being overweight or obese. Reducing leisure-time sedentary behaviours may be as important as increasing leisure-time physical activity as a strategy to fight against obesity in adults.

The infant feeding activity and nutrition trial (INFANT) an early intervention to prevent childhood obesity : cluster-randomised controlled trial

Background : Multiple factors combine to support a compelling case for interventions that target the development of obesity-promoting behaviours (poor diet, low physical activity and high sedentary behaviour) from their inception. These factors include the rapidly increasing prevalence of fatness throughout childhood, the instigation of obesity-promoting behaviours in infancy, and the tracking of these behaviours from childhood through to adolescence and adulthood. The Infant Feeding Activity and Nutrition Trial (INFANT) aims to determine the effectiveness of an early childhood obesity prevention intervention delivered to first-time parents. The intervention, conducted with parents over the infant's first 18 months of life, will use existing social networks (first-time parent's groups) and an anticipatory guidance framework focusing on parenting skills which support the development of positive diet and physical activity behaviours, and reduced sedentary behaviours in infancy.

Methods/Design : This cluster-randomised controlled trial, with first-time parent groups as the unit of randomisation, will be conducted with a sample of 600 first-time parents and their newborn children who attend the first-time parents' group at Maternal and Child Health Centres. Using a two-stage sampling process, local government areas in Victoria, Australia will be randomly selected at the first stage. At the second stage, a proportional sample of first-time parent groups within selected local government areas will be randomly selected and invited to participate. Informed consent will be obtained and groups will then be randomly allocated to the intervention or control group.

Discussion : The early years hold promise as a time in which obesity prevention may be most effective. To our knowledge this will be the first randomised trial internationally to demonstrate whether an early health promotion program delivered to first-time parents in their existing social groups promotes healthy eating, physical activity and reduced sedentary behaviours. If proven to be effective, INFANT may protect children from the development of obesity and its associated social and economic costs.

Parent's views of the importance of making changes in settings where children spend time to prevent obesity

Aim : To examine the kinds of changes parents would like to see in those settings where children spend time (kindergartens and schools, child care centres and after-school care facilities, and the local neighbourhood) in policies and practices that impact on children’s risk of obesity, and to establish whether parents might be willing to advocate for changes in these settings.

Materials and Methods : 175 parents from five randomly selected primary schools and five randomly selected kindergartens located in suburbs of metropolitan Melbourne completed a questionnaire in which they rated the importance of a number of potential changes to promote healthy eating and increase physical activity in their children.

Results : Parents of children in kindergarten most commonly rated changes to the eating environment as important. In contrast, parents of primary school children believed changes related to both eating and physical activity in school were important. Ninety-five per cent of parents of kindergarten children and 89% of parents of primary school children believed it was possible for parents to bring about change to provide more opportunities for their child to eat more healthily and be more physically active. One in four parents reported that they had thought about or had tried to bring about changes in their community.

Conclusions : The findings suggest that mobilising parents to take an active role in advocating for change in those settings that have the potential to shape their children’s physical activity and eating behaviours may be feasible.