Non-nutritive sweetened beverages versus water after a 52-week weight management programme: a randomised controlled trial.

BACKGROUND/OBJECTIVE: Sugar-sweetened beverages are a substantial source of dietary sugar that can contribute to weight gain and the risk of type 2 diabetes. Dietary guidelines recommend non-nutritive sweetened (NNS) beverages to reduce sugar consumption, however, there is a need for long-term randomised controlled trials on their use. We aimed to compare the effects of NNS beverages and water on body weight during weight loss and maintenance in a behavioural weight management programme. METHODS: In this parallel-group, open-label, controlled equivalence trial, adults with a BMI of 27-35 kg/m2 who regularly consumed cold beverages were randomised 1:1 to water or NNS beverages. Participants underwent a group behavioural weight management programme comprising weekly (during the 12-week weight-loss phase) then monthly (during the 40-week weight-maintenance phase) meetings. The primary endpoint was weight change at week 52 (equivalence: two-sided P > 0.05). Secondary endpoints included changes in anthropometrics, cardiometabolic risk factors, appetite and activity levels. RESULTS: Of 493 participants randomised (water: n = 246; NNS beverages: n = 247), 24.1% were NNS-naïve. At week 52, water and NNS beverages were non-equivalent, with significantly greater weight loss in the NNS beverages group. Participants consuming water maintained a weight loss of 6.1 kg over 52 weeks versus 7.5 kg with NNS beverages (difference [90% CI]: 1.4 kg [-2.6, -0.2]; p < 0.05). CONCLUSIONS: During a 52-week behavioural weight management programme, water and NNS beverages were non-equivalent, with weight loss maintained to a statistically greater extent with NNS beverages compared with water. However, this difference was not clinically significant. CLINICAL TRIAL REGISTRATION: This trial is registered with ClinicalTrials.gov: NCT02591134.

The development and validation of the food insecurity physical activity concerns scale.

Food insecurity - defined as having limited access to nutritious foods - is linked with obesity. Previous research has also shown that food insecurity is associated with lower levels of leisure-time physical activity (physical activity performed outside of essential activities). This association may occur in part due to concerns about preserving levels of energy during times of food shortage. Currently, no scale exists which measures this construct. Therefore, we aimed to develop and validate such a scale - the food insecurity physical activity concerns scale (FIPACS). Participants (N = 603, individuals with food insecurity = 108) completed an online survey, consisting of the FIPACS, the International Physical Activity Questionnaire short-form (IPAQ), the restraint subscale of the Dutch Eating Behaviour Questionnaire (DEBQ), the amotivation subscale of the Behaviour Regulation In Exercise Questionnaire-2 (BREQ-2), and the Behavioural Inhibition System/Behavioural Approach System Reactivity scale (BIS/BAS) to assess convergent and divergent validity. An exploratory factor analysis revealed a four-factor model of the FIPACS - namely 'Concerns relating to hunger', 'Concerns of replenishment and calories', 'Concerns of physiological effects of exercise' and 'Compensatory behaviours' which was verified through a confirmatory factor analysis. To assess test-retest reliability, 100 participants completed the FIPACS again two weeks later. The FIPACS had good internal, test-retest reliability and divergent validity. However, there was limited evidence of convergent validity. Future studies could incorporate this scale when investigating the association between food insecurity and physical activity.

The impact of the cost of living crisis and food insecurity on food purchasing behaviours and food preparation practices in people living with obesity.

Lower income households are at greater risk of food insecurity and poor diet quality than higher income households. In high-income countries, food insecurity is associated with high levels of obesity, and in the UK specifically, the cost of living crisis (i.e., where the cost of everyday essentials has increased quicker than wages) is likely to have exacerbated existing dietary inequalities. There is currently a lack of understanding of the impact of the current UK cost of living crisis on food purchasing and food preparation practices of people living with obesity (PLWO) and food insecurity, however this knowledge is critical in order to develop effective prevention and treatment approaches to reducing dietary inequalities. Using an online survey (N = 583) of adults residing in England or Scotland with a body mass index (BMI) of ≥30 kg/m2, participants self-reported on food insecurity, diet quality, perceived impact of the cost of living crisis, and their responses to this in terms of food purchasing behaviours and food preparation practices. Regression analyses found that participants adversely impacted by the cost of living crisis reported experiencing food insecurity. Additionally, food insecurity was associated with use of specific purchasing behaviours (i.e., use of budgeting, use of supermarket offers) and food preparation practices (i.e., use of energy-saving appliances, use of resourcefulness). Exploratory analyses indicated that participants adversely impacted by the cost of living crisis and who used budgeting had low diet quality, whereas use of meal planning was associated with high diet quality. These findings highlight the fragility of food budgets and the coping strategies used by PLWO and food insecurity during the cost of living crisis. Policy measures and interventions are urgently needed that address the underlying economic factors contributing to food insecurity, to improve access to and affordability of healthier foods for all.

Impact of acute consumption of beverages containing plant-based or alternative sweetener blends on postprandial appetite, food intake, metabolism, and gastro-intestinal symptoms: Results of the SWEET beverages trial.

Project SWEET examined the barriers and facilitators to the use of non-nutritive sweeteners and sweetness enhancers (hereafter "S&SE") alongside potential risks/benefits for health and sustainability. The Beverages trial was a double-blind multi-centre, randomised crossover trial within SWEET evaluating the acute impact of three S&SE blends (plant-based and alternatives) vs. a sucrose control on glycaemic response, food intake, appetite sensations and safety after a carbohydrate-rich breakfast meal. The blends were: mogroside V and stevia RebM; stevia RebA and thaumatin; and sucralose and acesulfame-potassium (ace-K). At each 4 h visit, 60 healthy volunteers (53% male; all with overweight/obesity) consumed a 330 mL beverage with either an S&SE blend (0 kJ) or 8% sucrose (26 g, 442 kJ), shortly followed by a standardised breakfast (∼2600 or 1800 kJ with 77 or 51 g carbohydrates, depending on sex). All blends reduced the 2-h incremental area-under-the-curve (iAUC) for blood insulin (p < 0.001 in mixed-effects models), while the stevia RebA and sucralose blends reduced the glucose iAUC (p < 0.05) compared with sucrose. Post-prandial levels of triglycerides plus hepatic transaminases did not differ across conditions (p > 0.05 for all). Compared with sucrose, there was a 3% increase in LDL-cholesterol after stevia RebA-thaumatin (p < 0.001 in adjusted models); and a 2% decrease in HDL-cholesterol after sucralose-ace-K (p < 0.01). There was an impact of blend on fullness and desire to eat ratings (both p < 0.05) and sucralose-acesulfame K induced higher prospective intake vs sucrose (p < 0.001 in adjusted models), but changes were of a small magnitude and did not translate into energy intake differences over the next 24 h. Gastro-intestinal symptoms for all beverages were mostly mild. In general, responses to a carbohydrate-rich meal following consumption of S&SE blends with stevia or sucralose were similar to sucrose.

Weight-based discrimination in financial reward and punishment decision making: causal evidence using a novel experimental paradigm.

BACKGROUND/OBJECTIVES: Cross-sectional research has demonstrated weight-related stigma and discrimination, however experimental research providing causal evidence of financial-based weight discrimination is lacking. The aim of these preregistered experiments was to examine whether a novel paradigm in which participants attributed financial rewards and punishments could be used to detect weight bias. SUBJECTS/METHODS: One-hundred and twenty-one individuals participated in experiment 1 and one-hundred and sixty-six individuals participated in experiment 2. Both studies were conducted online, and participants were provided with biographies of hypothetical individuals in which weight-status was manipulated (normal weight vs. overweight/obesity) before being asked to provide rewards and punishments on their cognitive performance. In experiment 1 (within-participants design) participants observed one individual they believed to be normal weight and one individual they believed to be overweight/have obesity. In experiment 2 (between-participants design) participants observed one individual whilst also being provided with information about food addiction (Food addiction is real + individual with overweight/obesity vs. food addiction is a myth + individual with overweight/obesity vs control + individual with normal weight). RESULTS: In experiment 1, participants punished individuals who were described as having overweight/obesity to a greater extent to individuals who were normal weight (Hedge's g = -0.21 [95% CI: -0.02 to -0.41], p = 0.026), but there was no effect on rewards. They were also less likely to recommend individuals with overweight/obesity to pass the tasks (X2(1) = 10.05, p = 0.002). In experiment 2, participants rewarded individuals whom they believed were overweight/obese to a lesser extent than normal-weight individuals (g = 0.49 [95% CI: 0.16 to 0.83]. There was no effect on punishment, nor any impact of information regarding food addiction as real vs a myth. CONCLUSION: Using a novel discrimination task, these two experiments demonstrate causal evidence of weight-based discrimination in financial decision making.

Perceived weight-related stigma, loneliness, and mental wellbeing during COVID-19 in people with obesity: A cross-sectional study from ten European countries.

BACKGROUND: Increased weight-related stigma during the COVID-19 pandemic has amplified the need to minimise the impacts on mental wellbeing. We investigated the relationship between the perceived changes in the representation of obesity in the media and mental wellbeing during the pandemic in a sample of people with obesity across 10 European countries. We also investigated the potential moderating effect of loneliness. METHODS: Between September to December 2020 during the COVID-19 pandemic, participants reported data on demographics, mental wellbeing (measured by World Health Organisation Five Wellbeing Index and Patient Health Questionaire-4), loneliness (measured by De Jong Gierveld short scale), and perceived change in the representation of obesity in media (measured by a study-specific question) using the online, cross-sectional EURopean Obesity PatiEnt pANdemic Survey (EUROPEANS). Data were analysed using linear mixed-effects models, controlling for age, gender, body mass index, and shielding status, with random incept for country. RESULTS: The survey was completed by 2882 respondents. Most identified as female (56%) and reported their ethnicity as White or White-mix (92%). The total sample had a mean age of 41 years and a BMI of 35.4 kg/m2. During the peak of the pandemic, compared to pre-pandemic, perceiving more negative representation of people with obesity on social media was associated with worse psychological distress, depression, and wellbeing. Perceiving more positive representation, compared to no change in representation, of people with obesity on television was associated with greater wellbeing, yet also higher psychological distress and anxiety. Loneliness, as a moderator, explained ≤0.3% of the variance in outcomes in any of the models. CONCLUSIONS: Perceiving negative representation of obesity on social media was associated with poorer mental wellbeing outcomes during the pandemic; positive representation on television was associated with both positive and negative mental wellbeing outcomes. We encourage greater media accountability when representing people with obesity.

'Don't stop believing': The role of training beliefs in cognitive bias modification paradigms.

Cognitive Bias Modification (CBM) paradigms have previously been applied to target appetite (craving, hunger) and food intake, and are hypothesised to reduce unhealthy food consumption. However, inconsistencies in relation to training outcomes raise questions regarding the efficacy of CBM as a standalone intervention. Furthermore, individual level factors (such as belief in the intervention efficacy) may influence expectations of behaviour change following training. Across two pre-registered studies, our aim was to investigate how directly manipulating beliefs in relation to training purpose and effectiveness influenced food value and choice across two popular CBM paradigms (Inhibitory Control Training (ICT: Study 1) and Evaluative Conditioning (EC: Study 2)). In online studies, participants were presented with a paragraph describing the CBM technique positively (or an unrelated control message) prior to completing either active or control CBM training. Across both studies, the results revealed that active CBM training resulted in a reduction to unhealthy food value (relative to pre-training), but only when paired with a positive manipulation message. Participants who received a control message displayed no significant changes to food value, even where active CBM training was provided. These results suggest that participant beliefs and expectancies have important consequences for CBM effectiveness. Future research should further investigate these factors within CBM contexts to identify their role within successful behaviour change interventions.

The association between COVID-19 related food insecurity and weight promoting eating behaviours: The mediating role of distress and eating to cope.

Food insecurity (a lack of stable access to nutritious food) is reliably associated with higher BMI, although the underlying mechanisms are unclear. Past research indicates that this relationship may, in part, be explained by the distress of being food insecure and using food as a coping mechanism. While previous work has focused on long-term food insecurity, the first COVID-19 national lockdown presented a unique opportunity to establish if the same relationships existed for individuals experiencing pandemic related food insecurity. Adults in the United Kingdom (N = 211) were recruited three months after the first UK lockdown via social media. They completed questionnaires on COVID-19 related food insecurity, physical stress, psychological distress, eating to cope, drinking to cope, diet quality, and changes in weight promoting eating behaviours (e.g. consuming larger portions, increased snacking) since the start of the lockdown. A structural equation model revealed that food insecurity was indirectly associated with changes in weight promoting eating behaviours. As predicted, the more instances of pandemic related food insecurity, the more distress individuals reported. Distress was then associated with eating as a way of coping, which in turn was associated with increases in weight promoting eating behaviours. Food insecurity was also indirectly associated with diet quality, but this was via distress only. These results reflect similar pathways observed in individuals reporting chronic food insecurity and strengthens the evidence that distress and eating to cope are generic mediators of food insecurity and eating behaviour.

The effect of acute alcohol consumption on meal memory and subsequent food intake: Two laboratory experiments.

Altering the quality of episodic meal memories has been shown to affect subsequent food intake. Acute alcohol consumption disrupts memory formation and produces short-term overeating. In two studies, we investigated whether alcohol consumption can affect meal-related memories and later food intake. Study 1 (N = 60, 50% male) investigated how consumption of an alcoholic drink (0.5 g/kg) prior to consumption of a lunch meal affected meal memory of that lunch, and later food intake, compared with a placebo-alcohol. Findings revealed that alcohol consumption did not impair meal memory, and did not affect subsequent food intake. Study 2 (N = 72, 50% male) investigated whether, due to alcohol's retrograde facilitation effect (the enhancement of recall due to reduced interference at the point of exposure) consuming alcohol after consumption of a lunch meal could enhance meal memory, compared with when consumed before a lunch meal (both a dosage of 0.6 g/kg), and compared with consumption of a soft drink. Contrary to prediction, alcohol consumed after a lunch meal did not significantly increase meal memory. But, certain types of meal memory were impaired when alcohol was consumed before the meal, compared with consumption of a soft drink. Subsequent food intake did not differ between conditions. Taken together, findings suggest that alcohol intoxication can impair some forms of meal memory recall, likely due to disruption of memory formation during the encoding phase. However, there was no evidence that this impairment contributes towards alcohol-induced overeating.

The effect of alcohol on food-related attentional bias, food reward and intake: Two experimental studies.

Acute alcohol consumption has been shown to increase food intake, and long-term alcohol consumption may be a risk for weight gain. A potential, but under-studied, mechanism for this effect is alcohol's ability to enhance food reward. In two studies, participants consumed an alcoholic drink (Study 1: 0.3 grams of alcohol per kilogram of bodyweight (g/kg); Study 2: 0.6 g/kg) and a placebo-alcohol drink in a within-subjects design. In both studies, food-related appetitive and motivational states, and attentional bias (AB) towards food-related cues were measured. In Study 1 (N = 44), participants completed a visual probe task with concurrent recording of eye-movements which measured AB towards images of palatable foods, unpalatable foods, and non-food control items. Participants also completed measures of appetite and snack urge ratings, salivary response towards palatable foods and an ad libitum food taste test. In Study 2 (N = 84), participants completed a similar procedure, but completed a modified Stroop task which measured differences in food-related and alcohol-related AB across the two drink conditions. In Study 1, there was no difference in food-related AB between drink conditions, and no differences in snack urge, appetite ratings, salivary response, or food intake. In contrast, Study 2 showed an alcohol-induced increase in AB towards food, but not alcohol. Snack urge, alcohol urge ratings and ad libitum food intake were also higher after alcohol consumption, relative to the placebo. Collectively, these findings suggest that alcohol can increase food reward and food intake, but these effects may only occur at a higher dose.

Examining cognitive bias modification interventions for reducing food value and choice: Two pre-registered, online studies.

There is considerable interest in Cognitive Bias Modification (CBM) as a potential treatment for overweight/obesity. Inhibitory Control Training (ICT: also known as motor response training) and Evaluative Conditioning (EC) are two popular paradigms which rely on associatively learned responses (unhealthy food - > inhibition, or unhealthy food- > negative stimulus, respectively) through repeated cue-response contingencies. Both ICT and EC have demonstrated some effectiveness for reducing food intake, value and/or choice, when administered in the laboratory and online. However, studies have been criticised for inconsistencies in design (e.g. use of inadequate control groups) which makes it difficult to draw robust conclusions. In two pre-registered, online studies our aim was to examine active ICT (study 1: N = 170) and EC (study 2: N = 300) in multiple groups where the cue- > response contingencies were systematically varied (100%, 75%, 50%, 25%), before examining food-cue valuations and hypothetical food choice. In both studies varying the cue- > response contingencies did not lead to significant changes in food-cue devaluation following training. ICT did not substantially influence hypothetical food choice, whereas there was weak evidence that EC reduced choice for unhealthy foods, compared to a control group with 50% cue-response contingencies. Taken together both studies provide limited evidence for online CBM as a viable psychological treatment - at least through the mechanism of food-cue devaluation or changes in healthy and unhealthy food choice. Future research is needed to investigate the factors that contribute towards successful CBM training to critically evaluate the potential for these strategies within interventions.

Obesity, eating behavior and physical activity during COVID-19 lockdown: A study of UK adults.

Eating, physical activity and other weight-related lifestyle behaviors may have been impacted by the COVID-19 crisis and people with obesity may be disproportionately affected. We examined weight-related behaviors and weight management barriers among UK adults during the COVID-19 social lockdown. During April-May of the 2020 COVID-19 social lockdown, UK adults (N = 2002) completed an online survey including measures relating to physical activity, diet quality, overeating and how mental/physical health had been affected by lockdown. Participants also reported on perceived changes in weight-related behaviors and whether they had experienced barriers to weight management, compared to before the lockdown. A large number of participants reported negative changes in eating and physical activity behavior (e.g. 56% reported snacking more frequently) and experiencing barriers to weight management (e.g. problems with motivation and control around food) compared to before lockdown. These trends were particularly pronounced among participants with higher BMI. During lockdown, higher BMI was associated with lower levels of physical activity and diet quality, and a greater reported frequency of overeating. Reporting a decline in mental health because of the COVID-19 crisis was not associated with higher BMI, but was predictive of greater overeating and lower physical activity in lockdown. The COVID-19 crisis may have had a disproportionately large and negative influence on weight-related behaviors among adults with higher BMI.

Is urban growing of fruit and vegetables associated with better diet quality and what mediates this relationship? Evidence from a cross-sectional survey.

Urban agriculture (UA), the growing of fruits and vegetables in urban and peri-urban areas, may improve food security and access, public health and dietary quality on both a broad and personal scale. However, there is little research on the relationship between UA and diet, and potential mediating factors are also unclear. This study aimed to investigate if proximity to and engagement with UA is associated with better diet quality, and what accounts for this relationship. UK-based adults (N = 583, 69% Female) completed measures of proximity to and engagement with UA, perceived access to fruits and vegetables, health and ethical food choice motivations, connection with nature, psychological distress and dietary quality in an online survey. Participants were recruited from UA-related groups and the general public. Proposed relationships were analysed using a structural equation model. Greater proximity to and engagement with UA was associated with greater perceived access to fruits and vegetables, more health-related food choice motivations, more ethical-related food choice, feeling more connected with nature, and, surprisingly greater psychological distress. Furthermore, proximity to and engagement with UA was indirectly associated with better diet quality via health-, and ethical-related, food choice motivations. While the direct pathway between proximity to and engagement with UA and diet quality was not significant, UA is associated with better diet quality, partly via healthier and ethical food choice motivations. Upscaling UA may have benefits for dietary quality via these factors, and more research is needed to test causal relationships and understand these complex interactions.

Out of the lab and into the wild: The influence of portion size on food intake in laboratory vs. real-world settings.

External influences on eating behaviour, such as portion size, have been reliably shown to influence food intake in the laboratory. However, little research has examined whether laboratory settings under or overestimate the effect that external influences have on food intake compared to when studied in the real-world. In Study 1, 60 participants (mean age = 32 years) were randomized to consume a large (200 g) or small (100 g) portion of popcorn under controlled laboratory conditions and during a separate session in their home. Results showed that the effect of portion size on food intake was larger at home (d = 0.97) than in the laboratory (d = 0.56). Furthermore, participants reported feeling more relaxed eating at home compared to the laboratory. In Study 2, we examined whether comparable results were observed in a semi-naturalistic laboratory designed to resemble a home setting. 59 participants (mean age = 28 years) completed the same procedure as Study 1 in a standard and a semi-naturalistic laboratory setting. Although participants reported having higher levels of private self-awareness in the standard laboratory, the effect that portion size had on food intake did not differ between the standard laboratory (d = 0.50) and the semi-naturalistic laboratory (d = 0.49). The impact that external influences on eating, such as portion size, have on food intake in the real-world may be underestimated when studied under laboratory conditions.

Food-related attentional bias and its associations with appetitive motivation and body weight: A systematic review and meta-analysis.

Theoretical models suggest that food-related visual attentional bias (AB) may be related to appetitive motivational states and individual differences in body weight; however, findings in this area are equivocal. We conducted a systematic review and series of meta-analyses to determine if there is a positive association between food-related AB and: (1.) body mass index (BMI) (number of effect sizes (k) = 110), (2.) hunger (k = 98), (3.) subjective craving for food (k = 35), and (4.) food intake (k = 44). Food-related AB was robustly associated with craving (r = 0.134 (95% CI 0.061, 0.208); p < .001), food intake (r = 0.085 (95% CI 0.038, 0.132); p < .001), and hunger (r = 0.048 (95% CI 0.016, 0.079); p = .003), but these correlations were small. Food-related AB was unrelated to BMI (r = 0.008 (95% CI -0.020, 0.035); p = .583) and this result was not moderated by type of food stimuli, method of AB assessment, or the subcomponent of AB that was examined. Furthermore, in a between-groups analysis (k = 22) which directly compared participants with overweight/obesity to healthy-weight control groups, there was no evidence for an effect of weight status on food-related AB (Hedge's g = 0.104, (95% CI -0.050, 0.258); p = .186). Taken together, these findings suggest that food-related AB is sensitive to changes in the motivational value of food, but is unrelated to individual differences in body weight. Our findings question the traditional view of AB as a trait-like index of preoccupation with food and have implications for novel theoretical perspectives on the role of food AB in appetite control and obesity.

Reductions to main meal portion sizes reduce daily energy intake regardless of perceived normality of portion size: a 5 day cross-over laboratory experiment.

BACKGROUND: Smaller portions may help to reduce energy intake. However, there may be a limit to the magnitude of the portion size reduction that can be made before consumers respond by increasing intake of other food immediately or at later meals. We tested the theoretical prediction that reductions to portion size would result in a significant reduction to daily energy intake when the resulting portion was visually perceived as 'normal' in size, but that a reduction resulting in a 'smaller than normal' portion size would cause immediate or later additional eating. METHODS: Over three 5-day periods, daily energy intake was measured in a controlled laboratory study using a randomized crossover design (N = 30). The served portion size of the main meal component of lunch and dinner was manipulated in three conditions: 'large-normal' (747 kcal), 'small-normal' (543 kcal), and 'smaller than normal' (339 kcal). Perceived 'normality' of portion sizes was determined by two pilot studies. Ad libitum daily energy intake from all meals and snacks was measured. RESULTS: Daily energy intake in the 'large-normal' condition was 2543 kcals. Daily energy intake was significantly lower in the 'small-normal' portion size condition (mean difference - 95 kcal/d, 95% CI [- 184, - 6], p = .04); and was also significantly lower in the 'smaller than normal' than the 'small-normal' condition (mean difference - 210 kcal/d, 95% CI [- 309, - 111], p < .001). Contrary to predictions, there was no evidence that the degree of additional food consumption observed was greater when portions were reduced past the point of appearing normal in size. CONCLUSIONS: Reductions to the portion size of main-meal foods resulted in significant decreases in daily energy intake. Additional food consumption did not offset this effect, even when portions were reduced to the point that they were no longer perceived as being normal in size. TRIAL REGISTRATION: Prospectively registered protocol and analysis plan: https://osf.io/natws/; retrospectively registered: https://clinicaltrials.gov/ct2/show/NCT03811210.

Portion size normality and additional within-meal food intake: two crossover laboratory experiments.

Reducing food portion size could reduce energy intake. However, it is unclear at what point consumers respond to reductions by increasing intake of other foods. We predicted that a change in served portion size would only result in significant additional eating within the same meal if the resulting portion size was no longer visually perceived as 'normal'. Participants in two crossover experiments (Study 1: n 45; Study 2: n 37; adults, 51 % female) were served different-sized lunchtime portions on three occasions that were perceived by a previous sample of participants as 'large-normal', 'small-normal' and 'smaller than normal', respectively. Participants were able to serve themselves additional helpings of the same food (Study 1) or dessert items (Study 2). In Study 1 there was a small but significant increase in additional intake when participants were served the 'smaller than normal' compared with the 'small-normal' portion (m difference = 161 kJ, P = 0·002, d = 0·35), but there was no significant difference between the 'small-normal' and 'large-normal' conditions (m difference = 88 kJ, P = 0·08, d = 0·24). A similar pattern was observed in Study 2 (m difference = 149 kJ, P = 0·06, d = 0·18; m difference = 83 kJ, P = 0·26, d = 0·10). However, smaller portion sizes were each associated with a significant reduction in total meal intake. The findings provide preliminary evidence that reductions that result in portions appearing 'normal' in size may limit additional eating, but confirmatory research is needed.

Expert consensus on low-calorie sweeteners: facts, research gaps and suggested actions.

A consensus workshop on low-calorie sweeteners (LCS) was held in November 2018 where seventeen experts (the panel) discussed three themes identified as key to the science and policy of LCS: (1) weight management and glucose control; (2) consumption, safety and perception; (3) nutrition policy. The aims were to identify the reliable facts on LCS, suggest research gaps and propose future actions. The panel agreed that the safety of LCS is demonstrated by a substantial body of evidence reviewed by regulatory experts and current levels of consumption, even for high users, are within agreed safety margins. However, better risk communication is needed. More emphasis is required on the role of LCS in helping individuals reduce their sugar and energy intake, which is a public health priority. Based on reviews of clinical evidence to date, the panel concluded that LCS can be beneficial for weight management when they are used to replace sugar in products consumed in the diet (without energy substitution). The available evidence suggests no grounds for concerns about adverse effects of LCS on sweet preference, appetite or glucose control; indeed, LCS may improve diabetic control and dietary compliance. Regarding effects on the human gut microbiota, data are limited and do not provide adequate evidence that LCS affect gut health at doses relevant to human use. The panel identified research priorities, including collation of the totality of evidence on LCS and body weight control, monitoring and modelling of LCS intakes, impacts on sugar reduction and diet quality and developing effective communication strategies to foster informed choice. There is also a need to reconcile policy discrepancies between organisations and reduce regulatory hurdles that impede low-energy product development and reformulation.

Food waste concerns, eating behaviour and body weight.

Consumer food waste is now a significant social issue. However, given that the modern day food environment has become characterised by larger portion sizes of more energy-dense foods, personal concerns about wasting food may result in eating behaviours that promote excess energy intake and weight gain. Across 3 studies, we developed a brief (5-item) measure to quantify concerns about food waste and examined the relationships between food waste concerns, eating behaviour and body weight. In Study 1, we showed that our 5-item measure of food waste concerns has acceptable convergent and divergent validity, and test-retest reliability. We also found that concerns about wasting food were predictive of greater behavioural intentions to avoid food waste (e.g. eating leftovers). In Study 2, greater food waste concerns were associated with an increased tendency to plate-clear when eating (self-reported), but not with objectively measured body weight or likelihood of having overweight or obesity. In Study 3, we examined how much food participants consumed when served a large portion size of a lunchtime meal and found that food waste concerns did not directly or indirectly predict how much participants ate. Overall, we found evidence that concerns about food waste are related to self-reported intentions to minimize food waste and plate-clearing tendencies, but no evidence that food waste concerns are related to objectively measured energy intake in the laboratory or body weight.

'Eating to survive': A qualitative analysis of factors influencing food choice and eating behaviour in a food-insecure population.

Food insecurity affects approximately 8.4 million people in the UK, one of the worst levels in Europe. Food insecurity is associated with poor diet quality and obesity; however, the drivers of this relationship are unclear. This study used a qualitative approach to explore factors that influence food choice and eating behaviour in a food-insecure population in Liverpool, UK. Face-to-face interviews were conducted with adults (N = 24) who were clients at foodbanks. The interviews were informed by a semi-structured interview schedule, which focussed on access to food, factors influencing food choices, and strategies used to conserve food. Interview transcripts were analysed using inductive thematic analysis. Six themes were developed; 'Income', 'Cost of food', 'Accessibility of shops', 'Health issues', 'Food rationing strategies' and 'Worsened health outcomes'. Income was the most salient factor influencing participants' food choices with all participants reporting a constant struggle to afford food. Food decisions were primarily based on cost; most participants valued eating healthily but could not afford to do so. Strategies to ration food included skipping meals, consuming small portions, cooking in bulk, and prioritising children's food intake. The majority of participants reported pre-existing physical and/or mental health issues, but these were exacerbated by poor access to food leading to a vicious cycle of stress and worsening health issues. In conclusion, participants' food choices and eating behaviour seemed to be most strongly influenced by their level of income. Our findings provide insight into the range of strategies used by participants to conserve food and also highlight the mental health impact of food insecurity. Initiatives addressing income and the cost of healthy food are required.