It has been estimated by various authorities that about one-third of cancers in Western high-income societies are attributable to factors relating to food, nutrition and physical activity. Identifying with confidence specific associations between dietary patterns, foods, body composition or individual nutrients is not simple because of the long latent period for cancer development, its complex pathogenesis and the challenge of characterising the multidimensional aspects of diet and activity over a lifetime. Reliable conclusions must therefore be drawn not only from randomised controlled trials but from a variety of methodological approaches, judged within a classic framework for inferring causality. Using a newly-developed method with a protocol for standardising the literature search and for analysis and display of the evidence, nine independent academic centres have conducted systematic reviews addressing the causal associations between food, nutrition and physical activity and risk of development of seventeen cancers, as well as of weight gain and obesity. A review has also examined the efficacy of such interventions in subjects with cancer. The reviews have been assessed by an independent Panel of twenty-one international experts who drew conclusions with grades of confidence in the causality of associations and made recommendations. Recommendations are given as public health goals as well as for individuals.

Progressive involuntary weight loss, in particular the loss of lean tissue, is common in patients with advanced cancer and has long been recognised to result in a deterioration in performance status and quality of life, increased morbidity and mortality. The aetiology of such weight loss or cachexia is complex and involves both tumour and host responses. Thus, identification of patients who are or are likely to become cachectic has been problematic. In addition to a reduction in appetite and increased satiety leading to poor dietary intake, there is now increasing clinical evidence that the activation of a chronic ongoing systemic inflammatory response is one of the earliest and most important contributory factors to cachexia. Such findings help to explain the failure of simple nutritional programmes to reverse weight loss adequately in patients with cancer. In the present paper the development of an inflammation-based score is described, which is derived from the acute-phase proteins C-reactive protein and albumin and is termed the Glasgow prognostic score (GPS). Its value as a predictor of survival, independent of tumour stage, performance status and treatment (active or palliative), has been shown in a variety of advanced common solid tumours. The nature of the relationship between the GPS, appetite, body composition, performance status and quality of life of the patient with advanced cancer will be described. Recently, it has become evident that the systemic inflammatory response is also present in a smaller proportion of patients with primary operable cancer and is also predictive of disease progression and poor survival. The role of GPS in clinical decision making will be discussed.

Advances in the understanding of appetite are leading to a refined concept of disease cachexia and point to novel therapeutic strategies based on the manipulation of appetite. The complex social and psychological short-term influences on appetite obscure the fact that over the longer term appetite is tightly regulated by physiological considerations; the homeostatic control of energy balance. Like obesity, which is now viewed as a disorder of homeostasis, cachexia can be seen as an adaptive response to the disease state that becomes harmful when prolonged. Several lines of evidence implicate a disorder of appetite regulation in the pathogenesis of cachexia. As the only known circulating mediator of increased appetite the peptide hormone ghrelin has attracted attention as a potential therapy. Trials in patients with various chronic illnesses, including cancer and kidney failure, have demonstrated short-term increases in energy intake. Trials in patients with emphysema and heart failure have also shown benefits in clinical outcomes such as lean body mass and exercise capacity, and longer-term trials using oral analogues are being undertaken. As well as improving nutrition, ghrelin has a number of other actions that may be useful, including an anti-inflammatory effect; of interest since many cachexias are associated with inappropriate immune activation. The manipulation of appetite, in particular by ghrelin agonism, is emerging as an exciting potential therapy for disease cachexia. Future research should focus on the ascertainment of clinically-relevant outcomes, and further characterisation of the non-nutritional effects of this pathway.

Nasogastric enteral feeding is not tolerated in patients with gastric atony and in many critically-ill patients in whom gastric emptying may be delayed and in whom gastro-oesophageal regurgitation may lead to pulmonary aspiration of enteral feed and the development of pneumonia. Initial attempts to overcome these problems led to the development of post pyloric enteral feeding techniques with the infusion port of the tubes positioned in the duodenum. In many centres this technique is still the most practised post-pyloric enteral feeding technique. Nasoduodenal feeding tubes often retroperistalse into the stomach. The technique of choice, therefore, in these difficult patients is to position the infusion port of the feeding tube well distal to the ligament of trietz (post ligament of trietz nasojejunal enteral tube feeding). While nasogastric and nasoduodenal enteral feeding techniques have been shown to elicit a stimulatory exocrine pancreatic response, distal jejunal enteral feeding does not. During this mode of feeding the ileal brake is activated and pancreatic exocrine pancreatic secretion inhibited by the action of the released peptide YY and glucagon-like peptide-1 hormones, in turn the inhibition of pancreatic secretion being the result of inhibition of trypsin secretion. In the light of the findings showing the absence of a stimulatory pancreatic exocrine response to nasojejunal enteral feeding these patients should receive a predigested rather than a polymeric enteral diet.

The beneficial effects of long-chain (C chain ≥20) n-3 PUFA are well documented and, overall, increased intake reduces risk of CVD. Recent evidence also points to a role in reducing age-related decline in cognitive function. The two key fatty acids are EPA (20:5) and DHA (22:6), with current UK recommendation for adults being 450 mg EPA+DHA/d. Whilst some EPA and DHA can be synthesised in vivo from α-linolenic acid, recent data indicate this source to be very limited, suggesting that EPA and DHA should be classified as dietary essentials. In many parts of Europe the daily intake of EPA+DHA by adults and especially young adults (18–24 years) is <100 mg/d, since many never eat oily fish. Poultry meat contributes small but worthwhile amounts of EPA+DHA. Studies to enrich the EPA+DHA content of animal-derived foods mainly use fish oil in the diet of the animal. Recent work has shown that such enrichment has the potential to provide to the UK adult diet a daily intake of EPA+DHA of about 230 mg, with poultry meat providing the largest amount (74 mg). There are, however, concerns that the continued and possibly increased use of fish oils in animals' diets is not sustainable and alternative approaches are being examined, including the genetic modification of certain plants to allow them to synthesise EPA and DHA from shorter-chain precursors.

Consumers' food choices and dietary behaviour can be markedly affected by communication and information. Whether the provided information is processed by the receiver, and thus becomes likely to be effective, depends on numerous factors. The role of selected determinants such as uncertainty, knowledge, involvement, health-related motives and trust, as well as message content variables, are discussed in the present paper based on previous empirical studies. The different studies indicate that: uncertainty about meat quality and safety does not automatically result in more active information search; subjective knowledge about fish is a better predictor of fish consumption than objective knowledge; high subjective knowledge about functional foods as a result of a low trusted information source such as mass media advertising leads to a lower probability of adopting these foods in the diet. Also, evidence of the stronger impact of negative news as compared with messages promoting positive outcomes of food choices is discussed. Finally, three audience-segmentation studies based on consumers' involvement with fresh meat, individuals' health-related-motive orientations and their use of and trust in fish information sources are presented. A clear message from these studies is that communication and information provision strategies targeted to a specific audience's needs, interests or motives stand a higher likelihood of being attended to and processed by the receiving audience, and therefore also stand a higher chance of yielding their envisaged impact in terms of food choice and dietary behaviour.

Members of low-income households in the UK are more likely to have patterns of food and nutrient intakes that are less inclined to lead to good health outcomes in the short and long term. Health inequalities, including the likelihood of child and adulthood obesity, have long been documented in the UK and show little sign of improving so far, despite 10 years of attention from a government that has committed itself to addressing them. Following the Acheson Inquiry into Inequalities in Health (1998) in England a number of initiatives to tackle inequalities in food and diet were established, both nationally and within the devolved nations of Scotland, Wales and Northern Ireland. Nevertheless, until recently, there has been no overall strategic policy addressing the food and nutritional needs of low-income households. The present paper reviews how the problems have been constructed and understood and how they have been addressed, briefly drawing on recent evaluations of food and nutrition policies in Scotland and Wales. The contemporary challenge is to frame cross-cutting policy initiatives that move beyond simple targeting and local actions, encompass a life-course approach and recognise both the diversity of households that fall into ‘low-income’ categories and the need for ‘upstream’ intervention.

Among the measures recommended by the WHO to reduce the risk of obesity and non-communicable disease, the consumption of a diet rich in micronutrients but with a relatively-low energy density features prominently. However, only a small percentage of the UK population (<1) appears to be consuming the recommended diet. Dietary behaviour is strongly influenced by the dietary environment, shaped by food supplies, investment policies and advertising, to create an obesogenic food market. Substantial resources have been invested in food production of a sort that does not promote better health; agriculture and food supply sectors have benefited from decades of public-sector support, but this practice has encouraged the production of meat, dairy, oils and sugar and the withdrawal from sale of fruit, vegetables and fish. The result is an ‘obesogenic economy’, i.e. a market economy that encourages weight gain, in which children are a prime target. Interventions in the obesogenic market need to be considered and several opportunities are described in the present paper. Recent moves to strengthen national and international food policies aimed to promote healthier behaviour have been undertaken, but they will need political support if they are to be fully implemented. Alliances of public health interests can help to create that political support and promote health-enhancing environments.

In order to promote healthful nutrition, insight is needed into the determinants of nutrition behaviours. Behavioural determinant research and behavioural nutrition interventions have focused mostly on individual-level motivational factors. It has been argued that the individual's socio-cultural and physical environments may be the main determinants of nutrition behaviours. However, the theoretical basis and empirical evidence for environmental determinants of nutrition behaviours are not strong. The present paper is a narrative review informed by a series of systematic reviews and recent original studies on associations between environmental factors and nutrition behaviours to provide an overview and discussion of the evidence for environmental correlates and predictors of nutrition behaviour. Although the number of studies on potential environmental determinants of nutrition behaviours has increased steeply over the last decades, they include only a few well-designed studies with validated measures and guided by sound theoretical frameworks. The preliminary evidence from the available systematic reviews indicates that socio-cultural environmental factors defining what is socially acceptable, desirable and appropriate to eat may be more important for healthful eating than physical environments that define the availability and accessibility of foods. It is concluded that there is a lack of well-designed studies on environmental determinants of healthful eating behaviours. Preliminary evidence indicates that social environmental factors may be more important than physical environmental factors for healthful eating. Better-designed studies are needed to further build evidence-based theory on environmental determinants to guide the development of interventions to promote healthful eating.

Prevalence of obesity in preschool children has increased dramatically in recent years. The preschool years (age 3–6 years) have been regarded as critical for the programming of energy balance, via the concept of early ‘adiposity rebound’. Children who undergo early adiposity rebound are at increased risk of later obesity. Recent evidence suggests that associations between timing of adiposity rebound and later obesity may not reflect programming, but might denote that ‘obesogenic’ growth trajectories are often established by the preschool period. Studies of objectively-measured physical activity and sedentary behaviour in preschool children show that levels of physical activity are typically low and sedentary behaviour high. The review of evidence presented here is supportive of the hypothesis that physical activity is protective against obesity in the preschool period, and that sedentary behaviour, particularly television viewing, is obesogenic. Definitive evidence on dose–response relationships between physical activity, sedentary behaviour and obesity remain unclear. Dose–response evidence could be obtained fairly readily by intervention and longitudinal observational studies that use accelerometry in preschool children. The generalisability of much of the evidence base is limited and there is a need for research on the influence of physical activity and sedentary behaviour in the preschool years in the aetiology of obesity in the developing world.