Disentangling the neuroendocrine systems that regulate energy homeostasis and adiposity has been a long-standing challenge in pathophysiology, with obesity being an increasingly important public health problem. Adipose tissue is no longer considered a passive bystander in body-weight regulation. It actively secretes a large number of hormones, growth factors, enzymes, cytokines, complement factors and matrix proteins, at the same time as expressing receptors for most of these elements, which influence fuel storage, mobilisation and utilisation at both central and peripheral sites. Thus, an extensive cross talk at a local and systemic level in response to specific external stimuli or metabolic changes underpins the multifunctional characteristics of adipose tissue. In addition to the already-known adipokines, such as IL, TNFα, leptin, resistin and adiponectin, more recently attention has been devoted to ‘newcomers’ to the ‘adipose tissue arena’, which include aquaporin, caveolin, visfatin, serum amyloid A and vascular endothelial growth factor. While in vitro and in vivo experiments have provided extremely valuable information, the advances in genomics, proteomics and metabolomics are offering a level of information not previously attainable to help unlock the molecular basis of obesity. The potential and power of combining pathophysiological observations with the wealth of information provided by the human genome, knock-out models, transgenesis, DNA microarrays, RNA silencing and other emerging technologies offer a new and unprecedented view of a complex disease, conferring novel insights into old questions by identifying new pieces to the unfinished jigsaw puzzle of obesity.

The growth and development of the human skeleton requires an adequate supply of many different nutritional factors. Classical nutrient deficiencies are associated with stunting (e.g. energy, protein, Zn), rickets (e.g. vitamin D) and other bone abnormalities (e.g. Cu, Zn, vitamin C). In recent years there has been interest in the role nutrition may play in bone growth at intakes above those required to prevent classical deficiencies, particularly in relation to optimising peak bone mass and minimising osteoporosis risk. There is evidence to suggest that peak bone mass and later fracture risk are influenced by the pattern of growth in childhood and by nutritional exposures in utero, in infancy and during childhood and adolescence. Of the individual nutrients, particular attention has been paid to Ca, vitamin D, protein and P. There has also been interest in several food groups, particularly dairy products, fruit and vegetables and foods contributing to acid–base balance. However, it is not possible at the present time to define dietary reference values using bone health as a criterion, and the question of what type of diet constitutes the best support for optimal bone growth and development remains open. Prudent recommendations (Department of Health, 1998; World Health Organization/Food and Agriculture Organization, 2003) are the same as those for adults, i.e. to consume a Ca intake close to the reference nutrient intake, optimise vitamin D status through adequate summer sunshine exposure (and diet supplementation where appropriate), be physically active, have a body weight in the healthy range, restrict salt intake and consume plenty of fruit and vegetables.

There are a number of ways in which food can influence behaviour, including malnutrition, types of diet, eating habits, pharmacological effects, food allergy, fatty acid deficiency and possibly food additives. The range of behaviour affected is also wide, and includes attention, conduct disorder and mood. A particular focus of interest has been the effects of food on hyperactivity in children. There is some initial evidence that fatty acids may influence hyperactivity in children with specific learning disabilities. The findings also suggest that some food additives (colourings, flavourings and preservatives) may increase hyperactivity in children with behaviour problems. For children showing behaviour problems such as hyperactivity the use of dietary manipulation tends to be a more acceptable approach to treatment than the use of drugs. However, there needs to be awareness of the dangers of the use of unsupervised restriction diets with children, and the use of dietary treatments alone is not likely to be sufficient treatment for many children with attention-deficit hyperactivity disorder. A study is currently underway to investigate the possible effects of additives on behaviour in the general population of children.

Presented are longitudinal studies, extending from infancy (n 180) to 2 years of age (n 130) and 6 years of age (>70% participation) of diet and Fe status in a population with high birth weight, high frequency of breast-feeding and, at the time of the study, high intake of cow's milk during the weaning period. The association between socio-demographic and dietary factors was also studied, together with Fe status in early childhood and developmental status at 6 years. Fe status was found to be poorer than in the neighbouring Nordic countries. Every fifth 1-year-old was Fe-deficient (serum ferritin <12 μg/l and mean corpuscular volume <74 fl). It was demonstrated by regression analysis that Fe status was negatively associated with cow's milk consumption at 9–12 months (significant at >460 g/d) and was weakly positively associated with fish, meat and Fe-fortified cereal consumption. Fe-deficient infants had a shorter duration of breast-feeding, and breast-feeding was related to slower growth, which can protect from worsening Fe status. Fe deficiency was less common at ages 2 and 6 years. Maternal factors associated with lower adherence to the recommended infant diet were less education, lower age and smoking. In a multiple stepwise regression analysis that included food factors, socio-demographic factors were not found to be associated with Fe status. Fe-depleted and Fe-deficient 1-year-olds had lower fine motor scores when they were 6 years old than those who were not Fe-deficient or Fe-depleted. The findings of these studies have already led to changes in the local recommendations for diet in infancy. The results suggest that Fe deficiency at 12 months of age affects development at 6 years of age. The studies indicated that mothers with less education, who smoked and who were younger needed more guidance concerning recommendations about diet in infancy.

Body dissatisfaction is commonplace for teenage girls and is associated with dieting and unhealthy weight-control behaviours. The idealisation and pursuit of thinness are seen as the main drivers of body dissatisfaction, with the media prominent in setting thin body ideals. Television and consumer magazine production in the UK are extensive, annually releasing 1×106 h programming and >3000 magazine titles. Their engagement by adolescent girls is high, and in surveys girls identify thin and revealing body images as influential to the appeal of thinness and their pursuit of dieting. Experimental studies show a short-term impact of these images on body dissatisfaction, especially in teenagers who are already concerned about body image. Magazine images appear more influential than television viewing. For many adolescents selecting thin-image media is purposive, permitting comparison of themselves with the models or celebrities featured. Indeed, the impact of the media needs to be understood within a social context, as engagement is often a highly-social process. Media influence is uneven because of differences in its content and manner of communication, and individual differences in vulnerability to its content. Greater social responsibility on the part of the media and better media literacy by children would be beneficial. For those working in adolescent nutrition it is a reminder that adolescent food choice and intake are subject to many competing, contradictory and non-health-related determinants.

The global epidemic of obesity in children will see a rise in the number of cases of metabolic syndrome, which is a clustering of CVD risk factors, including atherogenic levels of blood lipids, hyperinsulinaemia and raised blood pressure. Rather than excess general fatness (assessed by BMI), more specifically it is excess abdominal fatness, quantified by waist circumference measurement, which is a better measure of risk for these metabolic abnormalities in children of all ages. Insulin resistance, a consequence of excess visceral fat, is understood to be the driving force underpinning the metabolic syndrome. Consequently, assessment of abdominal fatness in children is proving to be more clinically useful. Waist circumference centile charts have now been developed for the UK and other paediatric populations to assist in this process. Furthermore, studies in the UK and elsewhere have shown that abdominal fatness has increased in infants, children and adolescents to a greater extent than overall fatness over the past 10–20 years, suggesting that obesity prevalence may be underestimated when based entirely on BMI. Additionally, ethnic differences in fat distribution have been demonstrated in children, with those from south Asian backgrounds having a greater abdominal distribution compared with Caucasian children and consequently having a much greater risk for type 2 diabetes. The information that can be provided by waist circumference measurement in children, as in adults, together with the recent changes in body fat distribution should provide the impetus for its measurement to be standardised and routinely taken in clinical and epidemiological settings.

With the increasing prevalence of childhood obesity, there is an urgent need to identify risk factors that are amenable to preventative action. However, there is a remarkable lack of consistency between studies that have investigated the relationships between measurements of physical activity and energy expenditure and body fatness in children. This disparity could be because energy intake is a more important determinant in preventing obesity. Alternatively, some of the conflicting results could be related to methodological limitations in assessing activity and body composition. Erroneous conclusions may be drawn if physical activity energy expenditure is not adjusted for differences in body composition, or body fat is not appropriately adjusted for body size. For public health purposes it may be more informative to evaluate the amount and intensity of physical activity required to prevent fat-mass gain than to assess energy expended in physical activity. The lack of consensus in the cut-off points applied to define intensity levels is severely hindering comparisons between studies using accelerometers that have examined relationships between activity intensity and body fatness. Thus, it is not currently possible to develop a firm evidence base on which to establish physical activity recommendations until the limitations are addressed and more prospective studies undertaken. In order to turn research into effective prevention strategies a clearer understanding of the psycho-social, behavioural and environmental factors that influence activity is needed, including the interactions between physical activity and other behaviours such as time spent sedentary, sleeping and eating.

Childhood obesity has reached a crisis stage and has become a population health issue. The few traditional systematic reviews that have been done to identify best practice provide little direction for action. The concept of evidence-based practice has been adopted in health care, and in medicine in particular, to determine best practice. Evidence-based medicine has its origins in the scientific method and for many researchers this concept means strict adherence to standards determining internal validity in order to justify a practice as evidence based. Practitioners addressing population health face challenges in identifying criteria for determining evidence, in part because of the nature of population health with its goal of shifting the health of whole populations. As well, the type of evidence provided by more traditional critical appraisal schema is limiting. Expanded approaches in finding and defining evidence have been proposed that use: expert panels; broad and inclusive search and selection strategies; appraisal criteria that incorporate context and generalizability. A recent synthesis of 147 programmes addressing childhood overweight and obesity provides a concrete example of using a broader approach to identify evidence for best practice (Flynn et al.2006). Incorporating evaluation and population health frameworks as criterion components in addition to traditional methodological rigour criteria, this synthesis has identified programmes that provide contextual information that can be used to populate what Swinburn et al. (2005) have described as the ‘promise table’. Using this approach a range in ‘certainty of effectiveness’ and a range in ‘potential for population impact’ are integrated to identify promising strategies. The exercise can provide direction for agencies and practitioners in taking action to address obesity.

Currently, the only treatment for any food hypersensitivity (including food allergy) is the dietary avoidance of the causative allergen, using an elimination diet. In addition to being used for the management of food hypersensitivity, an elimination diet may also be used in the diagnosis of food allergy. Dietary exclusion should be managed by a dietitian or other health professional with nutritional expertise to ensure that the exclusion does not lead to a nutritionally-deficient diet. There are three main types of elimination diets: single-food exclusion; multiple-food exclusion; the ‘few-food’ diet, which requires the avoidance of a large number of allergens and therefore concentrates on the foods that can be included rather than the foods that need to be avoided. Any sort of elimination diet is hard to manage. Thus, as well as ensuring that the diet is nutritionally adequate, it is essential that families are given advice and support relevant to their circumstances to aid them in the day-to-day management of the diet, so that it remains varied and enjoyable for food-allergy sufferers. This approach involves advice about which alternative foods are available, provision of ‘free-from’ recipes and guidance on which nutritional supplements are needed to meet their nutritional needs.

The present paper presents the approach, results and outcome of an innovative piece of action research amongst professionals (health and non-health) and the public (women and young people from low-income families in one of the deprived areas of Birmingham, UK). A cooperative inquiry approach was used and data were collected on concerns about health of professionals (n 15) and the public (n 19), as well as dietary practices, smoking pattern and access to healthy foods amongst the public (n 49). The methods of data collection were: desk research; observation; semi-structured individual and focus-group interviews; structured individual interviews. The findings highlight diverse views and expectations about health amongst the public and the professionals, and suggest the existence of tensions between the partnership and the ownership of inter-agency collaboration. It argues the importance of having a shared vision amongst health and non-health professionals regarding health strategy and the way forward for working together to promote the public's health. It recommends that by using the tenet of action research, and adapting a cooperative inquiry approach, members of a partnership project could learn through reflection on action and achieve personal development and social action.

The present paper reflects a practical activity undertaken by the Nutrition Society's qualitative research network in October 2005. It reflects the structure of that exercise. First, there is an introduction to feminist methodology and methods. The informing premise is that feminist methodology is of particular interest to practitioners (professional and/or academic) engaged in occupations numerically dominated by women, such as nutritionists. A critical argument is made for a place for feminist methodology in related areas of social research. The discussion points to the differences that exist between various feminist commentators, although the central aims of feminist research are broadly shared. The paper comprises an overview of organizing concepts, discussion and questions posed to stimulate discussion on the design and process of research informed by feminist methodology. Issues arising from that discussion are summarized.