The world is waking up to the reality of climate change and the challenge of feeding 10 billion people in a healthy and sustainable way. For population and planetary health, food systems need to change. ‘Food and nutrition: pathways to a sustainable future’ was the first face-to-face Nutrition Society Summer Conference since 2018, bringing together leading contributors from across the globe to explore six pathways to a better tomorrow. Review papers from the conference symposia cut across disciplinary divides showcasing advances in scientific methods and our cumulative understanding of the impact of the food system on climate change. The depth, breadth and advancement of research presented demonstrate the power of collaborative research that can shape industry, individual and population recommendations and create a powerful shift towards the sustainable dietary patterns and systems that are so urgently required.

Consumption of snacks and ultra-processed foods (UPF) high in fat, salt and sugar (HFSS) is associated with rising rates of obesity and growing socioeconomic disparities in nutrition. While infancy, childhood and adolescence are critical periods for development of dietary preferences, there remains a dearth of research exploring factors that underpin snacking behaviour over this time. This review aims to address this gap by drawing from qualitative lived experience research, with 122 families of different socioeconomic position (SEP), to explore how the (i) home food environment, (ii) food environment and (iii) social value and meanings of food shape parental provision of snacks. This review shows that snacking holds important meanings in everyday family life, with infants integrated into existing snacking practices from an early age. Price promotions, low-cost and long shelf-lives all make UPF and HFSS snacks an appealing option for many low-SEP parents; while children's requests and preferences for HFSS snacks present a challenge across SEP. However, higher-SEP parents can ensure fresh fruits are always available as an alternative snack, while fruit is described as a financially risky expenditure for low-SEP families. The present findings also indicate that retailers and producers are increasingly promoting ‘healthier’ snacks through product packaging and marketing, such as ‘meets one of your five a day’, despite these products displaying similar nutritional profiles to traditional UPF and HFSS snacks. We outline a series of policy recommendations, including extending Healthy Start Vouchers and the Fruit and Vegetable Scheme in schools and action to address misleading product marketing and packaging.

Excess body weight is associated with increased mortality and risk of developing CVD. Body fat distribution is now considered a better indicator of disease risk than BMI, with central adiposity associated with dyslipidaemia and insulin resistance. Dietary modification is unquestionably important in the prevention of obesity and CVD, with the type but not the amount of dietary fat emerging as an important determinant of both diseases. Although reducing SFA intake via replacement with unsaturated fatty acids (UFA) is a key public health strategy for CVD prevention, variability in the lipid lowering response has been observed. This narrative review aims to investigate the link between adiposity and CVD risk, and the role of dietary fat composition and APOLIPOPROTEIN (APO)E genotype on this relationship. In the absence of weight loss, replacing dietary SFA with UFA reduces central adiposity and anthropometric measures, and is linked with lower total and LDL-cholesterol concentrations. However, differences in study populations and body composition techniques need to be taken into consideration. To date, only a limited number of studies have determined the role of APOE on body composition and CVD risk, but findings are inconsistent. Both APOE2 and APOE4 alleles have been correlated with adiposity related markers, and an APOE genotype–BMI interaction has been reported on fasting lipids. However, studies are often performed retrospectively leading to small sample sizes within the genotype groups. Further studies are needed to confirm the relationship between APOE genotype, adiposity and circulating CVD risk markers.

This review makes a case for taking an integrated ‘food systems’ approach to explore the links between health and sustainability rather than treating them as separate topics. Unlike more linear ‘farm-to-fork’ conceptions, a systems approach emphasises the links between domains and sectors, helping avoid perverse effects where an intervention at one point in the system can have unanticipated consequences at other points. Adopting this approach, the review argues that food security and sustainability are as much a socio-cultural as a technical challenge requiring the combined forces of researchers from the natural and social sciences together with a range of stakeholders from government, business and civil society. Meeting the twin challenges of health and sustainability will require changes to intensive food production systems, dietary change and reductions in current levels of food waste. The review explores why dietary practices are so resistant to change seeking alternatives to the deficit thinking that pervades much advice on ‘healthy eating’. It explores the locus of responsibility for food system change, emphasising the asymmetrical power relations that shape contemporary dietary choices. The review includes an example of food system research, the H3 project (healthy soil, healthy food, healthy people), which seeks to transform UK food systems ‘from the ground up’, adopting the principles outlined in the body of the review.

The marketing of foods and non-alcoholic beverages (hereafter: food) high in fats, salt and/or sugar (HFSS) has been strongly implicated in the rising levels of childhood obesity worldwide. Multiple ethical concerns arise from the practice of exposing children to such marketing and efforts to monitor and restrict it through regulatory policies. There is considerable evidence that exposure to powerful food marketing messages affects children's food behaviours in ways that are detrimental to good dietary health. Children are particularly vulnerable to being exploited and deceived by food marketing messages based on their cognitive and developmental immaturity. HFSS food marketing also affects numerous child rights enshrined within the UN Convention on the Rights of the Child (of which the UK is a signatory) including the right to the enjoyment of the highest attainable standard of health. The debate has become somewhat polarised between the public health community's evidence-based assertion that all marketing is inherently exploitative and the rebuttal from food and marketing industry stakeholders that provided the marketing is ‘accurate and truthful’ and there is no ethical need to regulate. This polarisation is reflected in the complexity of policymaking decisions regarding the rationale for mandatory government-led policies or industry self-regulation. There are also ethical considerations inherent in the monitoring of children's food marketing exposure, particularly in the digital sphere, by researchers for the purposes of informing policy design, scope and implementation. This review paper will explore the latest evidence on these issues and consider the implications for public health research, policy, and practice.

Maternal nutrition is essential for optimal health and well-being of women and their infants. This review aims to provide a critical overview of the evidence-base relating to maternal weight, obesity-related health inequalities and dietary interventions encompassing the reproductive cycle: preconception, pregnancy, postnatal and interpregnancy. We provide an overview of UK data showing that overweight and obesity affects half of UK pregnancies, with increased prevalence among more deprived and minoritised ethnic populations, and with significant health and cost implications. The existing intervention evidence-base primarily focuses on the pregnancy period, where extensive evidence demonstrates the power of interventions to improve maternal diet behaviours, and minimise gestational weight gain and postnatal weight retention. There is a lack of consistency in the intervention evidence-base relating to interventions improving pregnancy health outcomes, although there is evidence of the potential power of the Mediterranean and low glycaemic index diets in improving short- and long-term health of women and their infants. Postnatal interventions focus on weight loss, with some evidence of cost-effectiveness. There is an evidence gap for preconception and interpregnancy interventions. We conclude by identifying that interventions do not address cumulative maternal obesity inequalities and overly focus on individual behaviour change. There is a lack of a joined-up approach for interventions throughout the entire reproductive cycle, with a current focus on specific stages (i.e. pregnancy) in isolation. Moving forward, the potential power of nutritional interventions using a more holistic approach across the different reproductive stages is needed to maximise the benefits on health for women and children.

The present paper reviews the growing body of literature on food insecurity and food bank use in the UK. It provides an overview of food insecurity in this context, followed by a description of the emergence of food banks, highlighting how any role that food banks play in the food insecure population is limited. Data on food insecurity and food bank use suggest many people experiencing food insecurity do not receive help from food banks. To better understand the factors influencing the relationship between food insecurity and food bank use, a conceptual framework is outlined, suggesting the relationship is far from straightforward and contingent on many factors. The nature and availability of food banks and other local support services and individual-level factors influence the likelihood of food banks being used in the context of food insecurity. Then, the extent to which food banks can impact food insecurity is also dependent on the quantity and quality of food distributed, as well as other support services offered from food banks. Closing reflections highlight rising living costs and food banks reporting that they do not have capacity to cope with increasing demand, underscoring the need for policy interventions. Reliance on food banks to respond to food insecurity may ultimately impede formulation of effective policy interventions to reduce food insecurity, giving the illusion of widespread available support, whilst food insecurity persists among those receiving help from food banks and those who experience food insecurity but do not use food banks.

The recent Covid-19 pandemic highlighted stark social inequalities, notably around access to food, nutrition and to green or blue space (i.e. outdoor spaces with vegetation and water). Consequently, obesity is socio-economically patterned by this inequality; and while the environmental drivers of obesity are widely acknowledged, there is currently little upstream intervention. We know that living with obesity contributes to increasing health inequalities, and places healthcare systems under huge strain. Our environment could broadly be described obesogenic, in the sense of supporting unhealthful eating patterns and sedentary behaviour. Evidence points to the existence of nearly 700 UK obesity policies, all of which have had little success. Obesity prevention and treatment has focused on educational and behavioural interventions targeted at individual consumers. A more sustainable approach would be to try and change the environments that promote less healthy eating and high energy intake as well as sedentary behaviour. Approaches which modify the environment have the potential to assist in the prevention of this complex condition. This review paper focuses on the role of wider food environments or foodscapes. While there is an imperfect evidence base relating to the role of the foodscape in terms of the obesity crisis, policy, practice, civic society and industry must work together and take action now, in areas where current evidence suggests change is required. Despite the current cost-of-living crisis, shaping the foodscape to better support healthful eating decisions has the potential to be a key aspect of a successful obesity prevention intervention.

The human health benefits of cardiometabolic disease prevention can be accompanied by planetary co-benefits. Focusing efforts towards young people, including children and adolescents, is conducive to disease prevention. In the context of cardiometabolic disease prevention, this review paper critically summarises the available literature on the acute cardiometabolic responses to physical activity and breakfast manipulations among young people. Given the seriousness of global climate change, which will disproportionally affect our younger generations, this review paper offers new insights into the inherent interactions between child–adolescent behaviour and cardiometabolic health from an environmental sustainability perspective to aid climate change mitigation efforts, including exploring future research avenues. A growing evidence base suggests acute moderate- to high-intensity exercise bouts can attenuate postprandial plasma glucose, insulin and triacylglycerol concentrations for up to 24–48 h in young people. Whether accumulating physical activity throughout the day with short, frequent bouts promotes cardiometabolic risk marker attenuations is unclear. Breakfast consumption may enhance free-living physical activity and reduce glycaemic responses to subsequent meals for a possible additive impact. If repeated habitually, attenuations in these cardiometabolic risk factors would be conducive to disease prevention, reducing the greenhouse gas emissions associated with disease diagnosis and treatment. To progress current understanding with high public health and planetary relevance, research among samples of ‘at risk’ young people that span cellular-level responses to ecologically valid settings and address human and planetary health co-benefits is needed. Indeed, certain physical activity opportunities, such as active travel to school, offer important direct co-benefits to humans and planetary health.

This review examines the ways in which physical activity can contribute to a sustainable future by addressing significant public health issues. The review begins by identifying obesity and ageing as two major challenges facing societies around the world due to the association of both with the risk of chronic disease. Recent developments in the understanding and treatment of obesity are examined followed by an appraisal of the role of exercise alone and in combination with other therapies in preventing and managing obesity. The review then addresses the interaction between exercise and appetite due to the central role appetite plays in the development of overweight and obesity. The final section of the review examines the potential of physical activity to combat age-related chronic disease risk including CVD, cancer and dementia. It is concluded that while bariatric surgery and pharmacotherapy are the most effective treatments for severe obesity, physical activity has a role to play facilitating and enhancing weight loss in combination with other methods. Where weight/fat reduction via exercise is less than expected this is likely due to metabolic adaptation induced by physiological changes facilitating increased energy intake and decreased energy expenditure. Physical activity has many health benefits independent of weight control including reducing the risk of developing CVD, cancer and dementia and enhancing cognitive function in older adults. Physical activity may also provide resilience for future generations by protecting against the more severe effects of global pandemics and reducing greenhouse gas emissions via active commuting.

This review considers current evidence on physical activity and dietary behaviours in the context of prostate cancer prevention and survivorship outcomes. Prostate cancer is the second most common cancer amongst men, with over 1⋅4 million newly diagnosed cases globally each year. Due to earlier detection via screening and advances in treatments, survival rates are amongst the highest of all cancer populations. However, hormone treatments (i.e. androgen deprivation therapy) can lead to undesirable body composition changes, increased fatigue and reduced health-related quality of life, which can impair the overall wellbeing of men living with and beyond prostate cancer. Existing research has only provided limited evidence that physical activity and nutrition can impact a man's risk of prostate cancer but cohort studies suggest they can influence survival outcomes after diagnosis. Additionally, data from observational and intervention studies suggest that habitual physical activity (or structured exercise) and healthy diets can help to ameliorate hormone-related treatment side-effects. Current physical activity guidelines state that prostate cancer patients should complete at least three sessions of moderate-intensity aerobic exercise per week, along with two resistance exercise sessions, but dietary guidelines for prostate cancer patients are less well defined. In conclusion, regular physical activity and nutritional interventions may improve survival outcomes and attenuate some adverse side-effects of hormone treatments in men with prostate cancer. However, further research is required to improve our understanding of the health impacts of physical activity (including structured exercise) and nutrition in relation to prostate cancer prevention and survivorship.

Modifiable lifestyle factors, such as improved nutrition, are crucial in maintaining cognitive health in older age. Fruit and vegetables represent healthy and sustainable sources of nutrients with the potential to prevent age-related cognitive decline. The aim of this review is to synthesise the available evidence, from epidemiological and randomised controlled trials (RCT), regarding the role of fruit and vegetables in sustaining healthy cognitive function. Epidemiological studies of combined fruit and vegetable intake suggest that increased consumption may sustain cognition in later life. The evidence appears to be stronger for an association between vegetables and cognition, particularly for green leafy and cruciferous vegetables. Specific benefits shown for berries, citrus fruits, avocado and nuts suggest fruit is worthy of further investigation in relation to cognition. Data from RCT indicate benefits to differing aspects of cognition following citrus and berry fruits, cocoa and peanuts, but the data are limited and there are a lack of studies exploring effects of vegetables. There is growing evidence for an association between fruit and vegetable intake and cognitive function, but this is not always consistent and the data from RCT are limited. Issues in previous research are highlighted, such as strict exclusion criteria, absence of baseline nutritional status data and lack of consideration of individual differences, which may explain the weaker findings from RCT. Inclusion of those most at risk for cognitive decline is recommended in future nutrition and cognition research.

Age-related frailty and cognitive decline are complex multidimensional conditions that significantly impact the ability of older adults to sustain functional capacity and independence. While underlying causes remain poorly understood, nutrition continually emerges as one associated risk element. Many studies have addressed the importance of adequate nutrition in delaying the onset of these conditions, but the specific role of micronutrients is not well established. The consideration of pre-frailty as an outcome variable is also limited in the current literature. In this review, we focus on the potential value of maintaining micronutrient sufficiency to sustaining the health of the ageing population. Using data from the Irish longitudinal study on ageing, we consider several vitamins known to have a high prevalence of low status in older adults and their impact on pre-frailty, frailty and cognitive impairment. They include vitamin B12 and folate, both of which are associated with multiple biological mechanisms involved in long-term health, in particular in cognitive function; vitamin D, which has been associated with increased risk of musculoskeletal disorders, depression and other chronic diseases; and the carotenoids, lutein and zeaxanthin, that may help mitigate the risk of frailty and cognitive decline via their antioxidant and anti-inflammatory properties. We show that low concentrations of folate and carotenoids are implicated in poorer cognitive health and that the co-occurrence of multiple nutrient deficiencies confers greatest risk for frailty and pre-frailty in the Irish longitudinal study on ageing cohort. These health associations contribute to evidence needed to optimise micronutrient status for health in the older adult population.

Type 2 diabetes (T2D) and CVD are major causes of mortality and chronic morbidity. Whilst mortality from CVD has decreased they remain the largest cause of death in Europe and the prevalence of T2D is increasing rapidly. A consistent component of public health advice is to reduce intake of SFA to reduce CVD in particular, which implies limiting dairy food consumption. The prospective studies and randomised controlled trials included in this review show that for dairy foods at least, SFA are not consistently associated with CVD or T2D risk. For CVD the association with dairy foods is generally neutral despite dairy foods being the major source of SFA in many diets. This creates considerable doubt, at least for dairy foods, concerning the validity of the traditional diet-heart hypothesis which positively relates SFA intake to increased serum LDL-cholesterol and subsequent increased CVD. There is now emerging evidence to explain this which is highly relevant to dairy foods. These include the potentially counterbalancing effect of SFA-stimulated HDL-cholesterol and specific food matrix factors. In addition, SFA are associated with the less atherogenic large buoyant LDL particles and possible counterbalancing hypotensive effects of dairy proteins. Overall, dairy foods have either a neutral or beneficial association with CVD and T2D. Beneficial associations are seen for blood pressure and the reduced T2D risk linked to yoghurt consumption, a subject that needs urgent attention given the sharp rise in T2D prevalence in many countries.

Phenotypic flexibility is a methodology that accurately assesses health in terms of mechanistic understanding of the interrelationship of multiple metabolic and physiological processes. This starts from the perspective that a healthy person is better able to cope with changes in environmental stressors that affect homeostasis compared to people with a compromised health state. The term ‘phenotypic flexibility’ expresses the cumulative ability of overarching physiological processes to return to homeostatic levels after short-term perturbations. The concept of phenotypic flexibility to define biomarkers for nutrition-related health was introduced in 2009 in the area of health optimisation and prevention and delay of non-communicable disease. The core approach consists of the combination of imposing a challenge test to the body followed by time-resolved analysis of multiple biomarkers. This new approach may better facilitate nutritional health research in intervention studies since it may show effects on early derailed physiological markers and the biomarker response can be extended by perturbing the system, thereby making them more sensitive in detecting health effects from food and nutrition. At the same time, interindividual variation can also be extended and compressed by challenge tests, facilitating the bridge to personalised nutrition. This review will overview where the science is in this research arena and what the phenotypic flexibility potential is for the nutrition field.

The overall aim of precision nutrition is to replace the ‘one size fits all’ approach to dietary advice with recommendations that are more specific to the individual in order to improve the prevention or management of chronic disease. Interest in precision nutrition has grown with advancements in technologies such as genomics, proteomics, metabolomics and measurement of the gut microbiome. Precision nutrition initiatives have three major applications in precision medicine. First, they aim to provide more ‘precision’ dietary assessments through artificial intelligence, wearable devices or by employing omic technologies to characterise diet more precisely. Secondly, precision nutrition allows us to understand the underlying mechanisms of how diet influences disease risk and identify individuals who are more susceptible to disease due to gene–diet or microbiota–diet interactions. Third, precision nutrition can be used for ‘personalised nutrition’ advice where machine-learning algorithms can integrate data from omic profiles with other personal and clinical measures to improve disease risk. Proteomics and metabolomics especially provide the ability to discover new biomarkers of food or nutrient intake, proteomic or metabolomic signatures of diet and disease, and discover potential mechanisms of diet–disease interactions. Although there are several challenges that must be overcome to improve the reproducibility, cost-effectiveness and efficacy of these approaches, precision nutrition methodologies have great potential for nutrition research and clinical application.

Present food systems threaten population and environmental health. Evidence suggests reduced meat and increased plant-based food consumption would align with climate change and health promotion priorities. Accelerating this transition requires greater understanding of determinants of plant-based food choice. A thriving plant-based food industry has emerged to meet consumer demand and support dietary shift towards plant-based eating. ‘Traditional’ plant-based diets are low-energy density, nutrient dense, low in saturated fat and purportedly associated with health benefits. However, fast-paced contemporary lifestyles continue to fuel growing demand for meat-mimicking plant-based convenience foods which are typically ultra-processed. Processing can improve product safety and palatability and enable fortification and enrichment. However, deleterious health consequences have been associated with ultra-processing, though there is a paucity of equivocal evidence regarding the health value of novel plant-based meat alternatives (PBMAs) and their capacity to replicate the nutritional profile of meat-equivalents. Thus, despite the health halo often associated with plant-based eating, there is a strong rationale to improve consumer literacy of PBMAs. Understanding the impact of extensive processing on health effects may help to justify the use of innovative methods designed to maintain health benefits associated with particular foods and ingredients. Furthering knowledge regarding the nutritional value of novel PBMAs will increase consumer awareness and thus support informed choice. Finally, knowledge of factors influencing engagement of target consumer subgroups with such products may facilitate production of desirable, healthier PBMAs. Such evidence-based food manufacturing practice has the potential to positively influence future individual and planetary health.

The consumption of larger portion sizes (PS) of food has been implicated in the increased prevalence of childhood obesity. The home is usually the first place children learn about food, however, little is known about how parents determine child PS in the home environment. This narrative review aimed to explore parental beliefs, decisions, strategies and barriers to the provision of appropriate food PS for children in the home environment. Results indicate that parental decisions on child food PS are based on the amounts they serve themselves, personal intuition and knowledge of child appetite. Owing to the habitual nature of food provision, parental decisions on child PS may be taken without conscious thought and/or could be part of a complex decision-making process influenced by several interlinked factors, including parental childhood mealtime experiences, other family members and child weight status. Strategies to determine child-appropriate PS include modelling the desired PS behaviour, use of unit-based food packaging and PS estimation aids, and providing the child with a degree of autonomy to rely on their own appetite cues. A lack of knowledge/awareness of PS guidance is a key barrier identified by parents to the provision of age-appropriate PS, warranting the inclusion of salient child-appropriate PS guidance within national dietary recommendations. Further home-based interventions to improve the provision of appropriate child PS are required, leveraged on parental strategies already in use, as outlined in this review.

Food-based dietary guidelines have been the basis of public health recommendations for over half a century, but more recently, there has been a trend to classify the health properties of food not by its nutrient composition, but by the degree to which it has been processed. This concept has been supported by many association studies, narrative reviews and the findings from one randomised controlled feeding trial, which demonstrated the sustained effect of ultra-processed diets on increasing both energy intake and body weight. This has led to widespread speculation as to specific features of ultra-processed foods that promote increased energy intakes. Rising interest in the ultra-processed topic has led to proposals to include guidance and restrictions on the consumption of processed foods in national dietary guidelines, with some countries encouraging consumers to avoid highly processed foods completely, and only choose minimally processed foods. However, there remains a lack of consensus on the role of processed foods in human health when faced with the challenges of securing the food supply for a growing global population, that is, healthy, affordable and sustainable. There has also been criticism of the subjective nature of definitions used to differentiate foods by their degree of processing, and there is currently a lack of empirical data to support a clear mechanism by which highly processed foods promote greater energy intakes. Recommendations to avoid all highly processed foods are potentially harmful if they remove affordable sources of nutrients and will be impractical for most when an estimated two-thirds of current energy purchased are from processed or ultra-processed foods. The current review highlights some considerations when interpreting the dietary association studies that link processed food intake to health and offers a critique on some of the mechanisms proposed to explain the link between ultra-processed food and poor health. Recent research suggests a combination of higher energy density and faster meal eating rates are likely to influence meal size and energy intakes from processed foods and offers new perspectives on how to manage this in the future. In going beyond the ultra-processed debate, the aim is to summarise some important considerations when interpreting existing data and identify the important gaps for future research on the role of processed food in health.