The food system and climate change: are plant-based diets becoming unhealthy and less environmentally sustainable?

A plant-based diet, which can include small amounts of meat, is the foundation for healthy sustainable diets, which will have co-benefits for health, climate and the environment. Studies show that some of the barriers to making this dietary change and reducing meat consumption are perceptions that plant-based diets are inconvenient, it takes too much time and skills to prepare meals and ingredients are expensive. The food environment is changing and the industry is responding with the exponential increase in the market of highly processed, convenient and cheap plant-based foods. This overcomes some of the barriers, but there is concern about whether they are healthy and environmentally sustainable. Plant-based foods have a halo effect around health and the environment, but many being produced are ultra-processed foods that are high in energy, fat, sugar and salt and have a higher environmental impact than minimally processed plant-based foods. The trend towards eating more highly processed plant-based convenience foods is a concern with regard to both public health and the targets set to reduce greenhouse gas (GHG) emissions. The 'modern day' plant-based diet emerging is very different to a more traditional one comprising pulses, vegetables and wholegrain. Studies show that those who are younger and have been a vegetarian for a shorter duration are eating significantly more ultra-processed plant-based foods. While there is a place for convenient, desirable and affordable plant-based food to encourage dietary change, care should be taken that this does not subconsciously set a path which may ultimately be neither healthy nor sustainable.

Social, temporal and situational influences on meat consumption in the UK population.

The amount of meat consumed is having a negative impact on both health and the environment. This study investigated the probability of eating meat and the amount eaten at a meal within different social, temporal and situational contexts. Dietary intake data from 4-day diet diaries of adults (19 years and above) taken from the UK National Diet and Nutrition Survey (2008/9-2013/14) were used for the analysis. Individual eating occasions were identified and the effects of where the food was eaten, with whom, day of the week, age and gender on the probability of eating meat and amount of meat eaten were modelled using general linear mixed models. Each factor showed distinctive effects on the probability of eating meat and the amount consumed. The amount of meat eaten was greater when eating with family members compared to when alone or with other companions. Both the probability and amount of meat eaten in a single eating occasion were higher on Sundays compared to the rest of the week. Eating out (e.g. restaurants/cafes) increased the probability of consuming meat and the amount compared to other situations (e.g. home, work). When considering the factors influencing meat consumption, attention must be paid to the effects of social, temporal, and situational factors as they all work to shape consumption behaviour. This information should be used in the design of interventions and development of policies for the most effective way to reduce meat consumption.

Nutrition from a climate change perspective.

Climate change is threatening future global food and nutrition security. Limiting the increase in global temperature to 1·5 °C set out in The Paris Agreement (2015) while achieving nutrient security means overhauling the current food system to create one that can deliver healthy and sustainable diets. To attain this, it is critical to understand the implications for nutrition of actions to mitigate climate change as well as the impacts of climate change on food production and the nutrient composition of foods. It is widely recognised that livestock production has a much greater environmental burden than crop production, and therefore advice is to reduce meat consumption. This has triggered concern in some sectors about a lack of protein in diets, which hence is driving efforts to find protein replacements. However, in most high- and middle-income countries, protein intakes far exceed dietary requirements and it would even if all meat were removed from diets. Reduction in micronutrients should be given more attention when reducing meat. Simply eating less meat does not guarantee healthier or more sustainable diets. Climate change will also affect the type, amount and nutrient quality of food that can be produced. Studies have shown that increased temperature and elevated CO2 levels can reduce the nutrient density of some staple crops, which is of particular concern in low-income countries. Nutrition from a climate change perspective means considering the potential consequences of any climate action on food and nutrition security. In this paper, we discuss these issues from an interdisciplinary perspective.

Social deprivation is associated with poorer adherence to healthy eating dietary goals: analysis of household food purchases.

Background: The Scottish Dietary Goals (SDGs) were published to promote healthier diets. The higher cost of healthier diets may be a barrier to their adoption by households in deprived areas. The aim was to estimate dietary intakes relevant to the SGDs, derived from purchase data of food and drinks brought into the home by area of deprivation. Methods: A cross-sectional study of estimated intakes of food and nutrients, and on fruit and vegetables (F&V) specifically, from Kantar Worldpanel household food purchase data in Scotland from 2012 (n = 2586). Households were grouped by area based index of multiple deprivation. Results: Diets of households were further from achieving the SDGs as deprivation increased. Linear regression showed that estimated intakes of oil rich fish decreased, and red and processed meat increased with increasing deprivation (both P < 0.001), while estimated intakes of F&V decreased (P < 0.001) mainly because of lower amounts of fresh F&V (P < 0.001). Negative linear associations were observed between deprivation and the amount spent per person on F&V (P < 0.001), and the amount spent per 100 g of F&V (P < 0.001). Conclusions: This study provides further insights into the relationship between social deprivation and diet quality in Scotland, notably in amounts of fresh F&V purchased.

Dietary patterns of households in Scotland: Differences by level of deprivation and associations with dietary goals.

BACKGROUND: Foods tend to be consumed in combinations, and dietary pattern analysis and diet-quality scores are often more appropriate methods of assessing overall diet quality than is intakes of individual foods or nutrients. AIM: The aim of this study was to evaluate dietary patterns from the food and drink purchases of households in Scotland, and to identify any dietary patterns that were associated with closer adherence to the Revised Dietary Goals for Scotland (RDGS). METHODS: We carried out a cross-sectional study of estimated food and drink intakes using Kantar WorldPanel household purchase data in Scotland collected during 2012. The amounts of food and drink purchased were converted to estimated amounts available for consumption per person by adjusting for household waste, household size and composition ( n = 720). Dietary patterns were identified using principal components analysis. A Diet Quality Index (DQI), based on the RDGS, was calculated. RESULTS: The mean DQI score was low at 38 out of a possible maximum of 100, indicating that, on average, few of the dietary goals were being met. Six dietary patterns were identified, which explained 35% of the total variance in estimated food and drink intake. Three dietary patterns showed statistically significant associations with lower DQI scores (less healthy diets), and one with significantly higher DQI scores (healthier diets). CONCLUSIONS: Investigating dietary patterns to show which foods tend to be purchased together may assist in targeting dietary habits by focussing on key food groups, and in gaining the greatest improvement in diet quality from the most achievable change in diet.

Perceived barriers towards healthy eating and their association with fruit and vegetable consumption.

Background: Improving dietary intakes is a key public health target. Perceived barriers to healthy eating (PBHE) are an important component of the Health Belief Model which aims to understand why individuals do not adopt preventive health measures. This study investigates the relationship between PBHE and reported fruit and vegetable (F&V) consumption. Methods: Data from the Scottish Health Survey 2008-11 (n = 8319) for PBHE and self-reported F&V consumption were used in Probit regression models to test the association between meeting the 400 g per day F&V recommendation and PBHE. Results: Regression models show women who reported a lack of cooking skills were 10.4% less likely to meet the F&V recommendations (P = 0.001). Not liking the taste of healthy foods or finding them too boring (10.2%, P = 0.022), preparation time (5.6%, P = 0.020) or willpower (3.0%, P = 0.021) were also significant. For men, reporting not liking the taste of healthy foods or finding them too boring (6.8%, P = 0.02) was the only significant result. Price, a commonly reported PBHE, was not significantly associated with F&V consumption. Conclusions: Not all commonly reported perceived barriers to healthy eating are significantly associated with meeting the recommended F&V intake.

Using food intake records to estimate compliance with the Eatwell Plate dietary guidelines.

BACKGROUND: The UK Eatwell Plate is consumer based advice recommending the proportions of five food groups for a balanced diet: starchy foods, fruit and vegetables, dairy foods, nondairy sources of protein and foods and drinks high in fat or sugar. Many foods comprise ingredients from several food groups and consumers need to consider how these fit with the proportions of the Eatwell Plate. This involves disaggregating composite dishes into proportions of individual food components. The present study aimed to match the diets of adults in Scotland to the Eatwell Plate dietary recommendations and to describe the assumptions and methodological issues associated with estimating Eatwell Plate proportions from dietary records. METHODS: Foods from weighed intake records of 161 females and 151 males were assigned to a single Eatwell group based on the main ingredient for composite foods, and the overall Eatwell Plate proportions of each subject's diet were calculated. Food group proportions were then recalculated after disaggregating composite foods. RESULTS: The fruit and vegetables and starchy food groups consumed were significantly lower than recommended in the Eatwell Plate, whereas the proportions of the protein and foods high in fat or sugar were significantly higher. Failing to disaggregate composite foods gave an inaccurate estimate of the food group composition of the diet. CONCLUSIONS: Estimating Eatwell Plate proportions from dietary records is not straightforward, and is reliant on methodological assumptions. These need to be standardised and disseminated to ensure consistent analysis.

Restoring expression of miR-16: a novel approach to therapy for malignant pleural mesothelioma.

BACKGROUND: Malignant pleural mesothelioma (MPM) is recalcitrant to treatment and new approaches to therapy are needed. Reduced expression of miR-15/16 in a range of cancer types has suggested a tumour suppressor function for these microRNAs, and re-expression has been shown to inhibit tumour cell proliferation. The miR-15/16 status in MPM is largely unknown. MATERIALS AND METHODS: MicroRNA expression was analysed by TaqMan-based RT-qPCR in MPM tumour specimens and cell lines. MicroRNA expression was restored in vitro using microRNA mimics, and effects on proliferation, drug sensitivity and target gene expression were assessed. Xenograft-bearing mice were treated with miR-16 mimic packaged in minicells targeted with epidermal growth factor receptor (EGFR)-specific antibodies. RESULTS: Expression of the miR-15 family was consistently downregulated in MPM tumour specimens and cell lines. A decrease of 4- to 22-fold was found when tumour specimens were compared with normal pleura. When MPM cell lines were compared with the normal mesothelial cell line MeT-5A, the downregulation of miR-15/16 was 2- to 10-fold. Using synthetic mimics to restore miR-15/16 expression led to growth inhibition in MPM cell lines but not in MeT-5A cells. Growth inhibition caused by miR-16 correlated with downregulation of target genes including Bcl-2 and CCND1, and miR-16 re-expression sensitised MPM cells to pemetrexed and gemcitabine. In xenograft-bearing nude mice, intravenous administration of miR-16 mimics packaged in minicells led to consistent and dose-dependent inhibition of MPM tumour growth. CONCLUSIONS: The miR-15/16 family is downregulated and has tumour suppressor function in MPM. Restoring miR-16 expression represents a novel therapeutic approach for MPM.

"It was an education in portion size". Experience of eating a healthy diet and barriers to long term dietary change.

The aim of the study was to explore the expectations and experience of actually eating a healthy diet and using this experience to identify barriers to healthy eating and sustainable dietary change. Fifty participants (19-63 yrs) were provided with a healthy diet (i.e. complied with dietary recommendations) for three consecutive days. Afterwards a semi-structured interview was carried out to explore expectations, experience and barriers to healthy eating. Using a thematic analysis approach eight dominant themes emerged from the interviews. Four related to expectations and experience of healthy eating; realisation of what are appropriate portion sizes, an expectation to feel hungry, surprise that healthy diets comprised normal food, the desire for sweet snacks (e.g. chocolate). This demonstrated there are some misconception about healthy eating and distorted views of portion size. Four more themes emerged relating to barriers to healthy eating; competing priorities, social, peer and time pressure, importance of value for money, a lack of desire to cook. Poor knowledge of healthy eating or a lack of cooking skills were the least common barrier, suggesting that future interventions and policy to improve dietary intakes need to focus on social, cultural and economic issues rather than on lack of knowledge or skills.

Meal and snacking patterns of school-aged children in Scotland.

BACKGROUND: Current lifestyles and the choice and availability of foods may influence the eating patterns of children. The aim of this study was to investigate the meal and snacking patterns of school-aged children in Scotland. METHODS: A sub-sample of 156 children (5-17 years) from the national Survey of Sugar Intake among Children in Scotland completed a 4-day non-weighed diet diary. Meals and snacks were defined using a food-based classification system based on 'core' and 'non-core' foods. The first eating event containing a solid food item up to and including 0900 hours (1100 hours on weekend days) was defined as breakfast. Frequency of meal and snack consumption was compared between age, sex, body mass index (BMI) and socio-economic sub-groups, between term-time and school holidays and between weekdays and weekend days. Intakes of total fat, saturated fatty acids (SFA) and non-milk extrinsic sugars (NMES) on these days were also compared. RESULTS: Children ate a median of 3.3 meals plus 2.0 snacks per day, which did not vary between age and BMI groups. In all, 83% of children ate breakfast on all 4 days. Boys ate more meals than girls but the number of snacks was similar. Children from lower socio-economic groups tended to eat more meals and fewer snacks. Snacks accounted for 21% of the total daily energy intake, 22% of total fat, 24% of SFA and 39% of NMES intake. Daily intake of energy, total fat, SFA and NMES did not differ between term-time and holidays or weekdays and weekend days. CONCLUSIONS: Children tended to follow a traditional pattern of three meals a day, which was consistent between age and BMI subgroups and between school term-time and holidays.

Epstein-Barr virus encoded latent membrane protein-1 induces epithelial cell proliferation and sensitizes transgenic mice to chemical carcinogenesis.

EBV is found to be associated with 100% of poorly or undifferentiated nasopharyngeal carcinomas, a tumor of epithelial origin. The latent membrane protein-1 (LMP1) of EBV, may play a causal role in the development of this disease. The experiments initiated here were designed to examine the activity of LMP1 in vivo in the epidermis of PyLMP1 transgenic mice in relation to its putative role in carcinogenesis. Transgenic positive epidermis showed a 2-3-fold increase in the mitotic index, coupled with an increased level of expression of proliferative cytokeratin markers (K6 and K14) over controls. These results provide direct evidence that LMP1 induces proliferation in otherwise normal epithelial cells in vivo. To assess the role of LMP1 in tumorigenic progression, transgenic mice were treated topically with chemical carcinogens. PyLMP1 mice were highly sensitive to chemical carcinogens, developing significantly more small papillomas at a faster rate than controls. Furthermore, LMP1 could substitute for 12-O-tetradecanoylphorbol-13-acetate treatment in tumor promotion. However, LMP1 inhibited expansion of the benign lesions and did not enhance progression of the lesions to carcinomas or the progression of these to the more malignant spindle cell carcinomas. These data demonstrate that, early in the carcinogenic process, LMP1 acts as a tumor promoter after chemical initiation; but, paradoxically, it may also introduce a hurdle against expansion or progression of a lesion.

Effects of Snack Intake on Appetite, Affect and Attention.

To test the hypothesis that snacks eaten in the afternoon influence appetite, affect and performance on a simple attention task, an experiment was conducted using a dose-response design. Thirty male volunteers attended the laboratory on five occasions to consume a standard lunch and then to eat a snack three hours later varying in size and carbohydrate/fat content. The effects of consuming four snacks of increasing energy content (124, 274, 424 and 724 kcal) on ratings of hunger, fullness, appetite and mood as well as reaction time and accuracy in a perceptual discrimination task were investigated. Although appetite variables were responsive to the dose-response manipulation, mood and performance were only weakly influenced by snack intake. Lunch produced a greater impact on mood than snack consumption. The larger snacks decreased fatigue and only marginally improved reaction time. It is concluded that when level of deprivation, sensory, hedonic and expectancy effects were controlled, snack intake produced relatively subtle effects on mood and attention.

The sugar-fat relationship revisited: differences in consumption between men and women of varying BMI.

OBJECTIVE: To assess the relationship of dietary fat and sugar consumption in men and women with different body mass indices (BMI). To determine the actual food sources for sugar intake, comparing differences between men and women across BMI groups. The effect of excluding individuals with low energy intakes (that is, invalid data) on these relationships was also incorporated in the analysis. SUBJECTS: Subjects for this analysis were those individuals who participated in the 1986-1987 Dietary and Nutrition Survey of British Adults (DNSBA). METHOD: In the DNSBA, dietary intake was assessed using seven-day weighed food records, providing estimates of dietary fat and sugar intake. From the DNSBA database food records, sources of sugar intake were classified into five sugar containing food groups (high fat sweet products, fruits, dairy products, sugar products (excluding soft drinks) and sugar products (including soft drinks)). BMI was calculated from the measurement of height and body weight. RESULT: A positive relationship between BMI and dietary fat intake was found for men, both when fat was expressed as a percentage of energy and in absolute terms (g/d). This relationship was only replicated for women when intake was expressed in absolute terms. A negative relationship was found between sugar intake (as a percentage of energy) and BMI in men, but not women. Expressing sugar consumption in absolute terms did not produce a statistically significant relationship with BMI for either men or women. In women the only sugar source associated with BMI was high fat sweet products (for example, cakes, biscuits, chocolate), where higher intakes were related to higher BMIs. The reverse relationship was found for men. In men, BMI was also negatively related to the intake of sugar products (for example, table sugar, preserves, sugar confectionery), both when soft drinks were included and excluded. The inclusion of low energy reporters (LER) in the analysis altered the relationships between nutrients and BMI, particularly among women. The association between overall fat intake (g/d) and BMI was weakened, while the negative relationship with sugar intake was strengthened. In the case of women, the inclusion of LER completely reversed the relationship between consumption of high fat sweet foods (cakes, biscuits, chocolate) and BMI (due to the reduced reporting of these products by obese women). Fewer alterations in the relationships between BMI and the sources of sugar consumed were observed in men than in women when LER were included in the analysis. CONCLUSION: The relationships between dietary fat, sugar and BMI are different in men and women, and are dependent on the inclusion of LER, particularly in women. The results suggest that among women the consumption of high fat sweet products may be a factor in understanding obesity. Furthermore, the observation of high consumption of these foods among obese women is consistent with measured preferences for these high fat sweet foods. The altered representation of the data created by LER appears to distort the relationship between sugar, fat and the degree of obesity in men and women.

Assessing dietary intake: Who, what and why of under-reporting.

Under-reporting of food intake is one of the fundamental obstacles preventing the collection of accurate habitual dietary intake data. The prevalence of under-reporting in large nutritional surveys ranges from 18 to 54% of the whole sample, but can be as high as 70% in particular subgroups. This wide variation between studies is partly due to different criteria used to identify under-reporters and also to non-uniformity of under-reporting across populations. The most consistent differences found are between men and women and between groups differing in body mass index. Women are more likely to under-report than men, and under-reporting is more common among overweight and obese individuals. Other associated characteristics, for which there is less consistent evidence, include age, smoking habits, level of education, social class, physical activity and dietary restraint. Determining whether under-reporting is specific to macronutrients or food is problematic, as most methods identify only low energy intakes. Studies that have attempted to measure under-reporting specific to macronutrients express nutrients as percentage of energy and have tended to find carbohydrate under-reported and protein over-reported. However, care must be taken when interpreting these results, especially when data are expressed as percentages. A logical conclusion is that food items with a negative health image (e.g. cakes, sweets, confectionery) are more likely to be under-reported, whereas those with a positive health image are more likely to be over-reported (e.g. fruits and vegetables). This also suggests that dietary fat is likely to be under-reported. However, it is necessary to distinguish between under-reporting and genuine under-eating for the duration of data collection. The key to understanding this problem, but one that has been widely neglected, concerns the processes that cause people to under-report their food intakes. The little work that has been done has simply confirmed the complexity of this issue. The importance of obtaining accurate estimates of habitual dietary intakes so as to assess health correlates of food consumption can be contrasted with the poor quality of data collected. This phenomenon should be considered a priority research area. Moreover, misreporting is not simply a nutritionist's problem, but requires a multidisciplinary approach (including psychology, sociology and physiology) to advance the understanding of under-reporting in dietary intake studies.

Fat as a risk factor for overconsumption: satiation, satiety, and patterns of eating.

Many people experience great difficulty in preventing energy intake from outstripping energy expenditure. Eating high-fat foods can facilitate the development of short-term positive energy balances by influencing satiation and satiety, the processes that control the size of eating episodes and the strength of postingestive appetite inhibition, respectively. An important feature of these processes is the relative potency of orosensory, postingestive (preabsorptive), and postabsorptive signals. Foods high in dietary fat have a weak effect on satiation, which leads to a form of passive overconsumption, and a disproportionately weak effect on satiety (joule-for-joule compared with protein and carbohydrate). This overconsumption (high-fat hyperphagia) is dependent upon both the high energy density and the potent sensory qualities (high palatability) of high-fat foods. A positive fat balance does not appear to generate a tendency for behavioral compensation, and there appears to be almost no autoregulatory link between fat oxidation and fat intake. The Leeds High Fat Study has found a higher frequency of obesity among high-fat than low-fat consumers, but the relationship between fat consumption and obesity is not a biologic imperative: analysis of the pathways between daily fat intakes and patterns of eating has revealed high-risk eating episodes. The physiologic responses to fat ingestion appear to be weak compared with the potent orosensory properties of high-fat foods, and such responses cannot prevent overconsumption. A first stage in a health program should be to prevent passive overconsumption.

High and low fat consumers, their macronutrient intake and body mass index: further analysis of the National Diet and Nutrition Survey of British Adults.

OBJECTIVES: To explore the different characteristics of high and low fat consumers, in particular their macronutrient intake and body mass index. DESIGN: Reanalysis of data from the Dietary and Nutritional Survey of British Adults. Comparisons were made between groups defined as high and low fat consumers on the basis of 7-day weighed food records considered to be valid for energy intake. Individuals were classified in two ways according to the percentage energy from fat (FAT%) and the absolute amount of fat consumed (FATg). The criteria for classification of the high FAT% being > 45% (high fat) and < or = 35% (low fat). For the FATg group the threshold for the high fat group was > 138 g/day (men) and > 102 g/day (women), and for the low fat group < 85 g/day (men) and < 70 g/day (women). SETTING: Dietary data was collected from private households in Great Britain between 1986 and 1987. SUBJECTS: From the total population of 2197, individuals who were slimming, ill or had an EI: BMR of < 1.2 were excluded in order to use data which was most likely to represent habitual energy intakes. From the remaining 1240 subjects, 10.8% of this sample (6.1% of the total population) were classified as low fat consumers (76 men and 58 women) and 15.4% high fat (8.7% of the total population, 93 men and 98 women). MAIN OUTCOME MEASURES: Macronutrient consumption and body mass index (BMI). RESULTS: 30% of the subjects changed fat group classification when the criteria of defining high and low fat groups altered from FAT% to FATg. Nutrient intakes differed according to definition of the groups. The high fat FATg group ate significantly more of all nutrients than the low fat FATg group. However, this was not seen for the FAT% analysis, with the high fat group eating more fat and less carbohydrate. The average BMI tended to be higher in the high fat than the low fat groups, particularly in the FATg analysis. However, the high fat group contained a wide range of BMIs. Further exploration of BMI in the high fat groups, showed that age (an 11-year difference) was the only variable to distinguish individuals in the top and bottom quartiles of BMI. CONCLUSIONS: High and low fat consumers differ according to a number of variables, and this is affected by how these groups are defined (FAT% or FATg). High fat consumers tend to have a higher BMI than low fat consumers, but not all high fat consumers are overweight or obese.