Investigating motivations to eat: Refining and validating a framework of Eating Behaviour Traits in dieters and the general population.

Due to relationships between diet and health including obesity, there is a need to examine the explanatory power of factors that motivate people to (over or under) eat. In a previous investigation, a four-factor subscale-based model of eating behaviour traits (EBTs) was developed which identified individual differences in psychological factors influencing motivations to eat and some residual uncertainties. The current study used a data-driven and theory-driven approach, including individual items to refine and extend previous EBT models. The aim was to examine and validate the domain structure of a framework for EBTs. The analysis used two samples including a representative sample of the UK population (n = 2010, 51% female, 49% male, 18 - 88 years), and members of a weight management program (n = 2317, 96.6% female, 2.8% male, 21 - 84 years), who completed 5 questionnaires including 10 EBTs. The results found some support for a 6-factor model, encompassing reactive eating, negative emotional eating, positive emotional eating, restricted eating, homeostatic eating, and body-food choice congruence (data-driven model) or eating for health (theory-driven model). There were differences between the data-driven model and the theory-driven model regarding the 6th factor. Additionally, the data-driven model did not distinguish between eating for pleasure and reactive eating. The models demonstrated that the eating behaviour factors were significantly associated with BMI category. Overall, this research contributes to a more structured understanding of the dimensions of motivation underlying EBTs, emphasising the utility of this framework for identifying at-risk individuals and tailoring interventions to meet specific individual needs.

Individual variability and consistency of post-exercise energy and macronutrient intake, appetite sensations, and food reward in healthy adults.

Limited evidence is available about the variability of appetitive responses within individuals after an acute bout of exercise. The present study aimed to assess the consistency and individual variability of post-exercise appetitive responses in healthy individuals. Twenty participants (10 females, 23.9 ± 4.1 years, 22.5 ± 2.0 kg m-2) joined the laboratory to perform four sessions separated by a minimum of 5 days: i) a control session with a rest period before and an ad libitum lunch (REST), and ii) three identical exercise sessions (EX) with a 30-min moderate-intensity (60-70% of predicted maximal heart rate) walking bout ending 25 min before the ad libitum lunch. Subjective appetite sensations were assessed before and after the meal at regular intervals, and satiety quotients were calculated. Food reward was assessed by the Leeds Food Preference Questionnaire before and after lunch. For each EX session, the difference with the REST session was calculated (Δ = EX - REST). Energy and macronutrient intake were consistent in response to exercise (all intraclass correlation coefficients (ICC) > 0.8) while results showed that post-exercise subjective appetite sensations and satiety quotients varied across the three EX sessions (almost all ICC < 0.7). Food reward was overall consistent in response to exercise before the test meal but not after. When considering the changes (Δ), the results showed no or poor consistency for most of the appetitive outcomes. To conclude, energy and macronutrient intake, as well as pre-meal food reward, are consistent after exercise in healthy individuals, while subjective appetite sensations are not stable within individuals across the sessions. Regarding the variations from REST to EX sessions, the results suggest that the individual changes observed are only random day-to-day variations.

Reward for fat and sweet dimensions of food are altered by an acute bout of running in healthy young men.

Acute moderate- to high-intensity exercise, primarily aerobic exercise, has been reported to decrease food reward in brain regions via the hedonic pathways and reduce preference for high-energy or high-fat foods. However, studies examining food reward responses to acute exercise have been limited to measuring food reward only after exercise and less frequently before and after exercise. Therefore, the changes in food reward in response to acute exercise remain unclear. This study investigated the effect of acute running on food reward in healthy young men. Fourteen young healthy men (mean ± standard deviation, age; 23 ± 2 years, body mass index; 21 ± 2 kg/m2) completed two trials (i.e., exercise and control) in a randomised, crossover design. Participants performed a 30-min running bout at 70% of maximal oxygen uptake or sitting rest before and after food reward evaluation with a computer-based food choice behaviour task tool. Food reward was assessed for foods varying in fat content and sweet taste, and there were four assessment parameters: explicit liking, explicit wanting, implicit wanting and frequency of choice of each food category (relative preference). Explicit and implicit wanting, and relative preference for high-fat relative to low-fat foods were reduced after the exercise trial compared to the control trial (trial-by-time interaction, all p ≤ 0.02). Implicit wanting and relative preference for sweet relative to savoury foods were increased after the exercise trial compared to the control trial (trial-by-time interaction, all p ≤ 0.003). These findings indicate that moderate-intensity acute running alters the reward bias away from high fat towards low fat foods and away from savoury towards sweet foods in healthy young men.

24-h passive heat and cold exposures did not modify energy intake and appetite but strongly modify food reward.

Effects of acute thermal exposures on appetite appear hypothetical in reason of very heterogeneous methodologies. The aim of this study was therefore to clearly define the effects of passive 24-h cold (16°C) and heat (32°C) exposures on appetitive responses compared to a thermo neutral condition (24°C). Twenty-three healthy, young, and active male participants realised three sessions (from 1 pm) in a laboratory conceived like an apartment dressed with the same outfit (Clo=1). Three meals composed of three or four cold or warm dishes were served ad libitum to assess energy intake (EI). Leeds Food Preference Questionnaires were used before each meal to assess food reward. Subjective appetite was regularly assessed and levels of appetitive hormones (acylated ghrelin, GLP-1, leptin, and PYY) were assessed before and after the last meal (lunch). Contrary to the literature, total EI was not modified by cold or heat exposure (p=0.120). Accordingly, hunger scores (p=0.554) were not altered. Levels of acylated ghrelin and leptin were marginally higher during the 16 (p=0.032) and 32°C (p<0.023) sessions, respectively. Interestingly, implicit wanting for cold and low-fat foods at 32°C and for warm and high-fat foods at 16°C were increased during the whole exposure (p < 0.024). Moreover, cold entrées were more consumed at 32 °C (p<0.062) and warm main dishes more consumed at 16°C (p<0.025). Thus, passive cold and hot exposures had limited effects on appetite and it seems that offering some choice based on food temperature may help individuals to express their specific food preferences and maintain EI.

Hedonic hunger, eating behavior, and food reward and preferences 1 year after initial weight loss by diet or bariatric surgery.

OBJECTIVE: The objective of this study was to investigate changes in hedonic hunger, eating behavior, and food reward and preferences at 1-year (1Y) follow-up after an initial weight loss (WL) induced by a 10-week, very low-energy diet alone (controls) or in combination with bariatric surgery. METHODS: Patients scheduled for sleeve gastrectomy or Roux-en-Y gastric bypass and controls were recruited. Body weight/composition, hedonic hunger (Power of Food Scale), eating behavior traits (Dutch Eating Behavior Questionnaire and Three-Factor Eating Questionnaire), and food reward and preferences (computerized behavioral task) were measured at baseline, 11 weeks, and 1Y follow-up. RESULTS: Changes in anthropometric variables were comparable across groups in the initial phase (week 11), and hedonic hunger decreased overall. The bariatric-surgery groups continued to lose body weight and fat mass, whereas weight regain was seen in controls at 1Y follow-up. Decreases in emotional eating, hunger, disinhibition, and food reward and increases in dietary restraint were seen at 1Y follow-up in the bariatric-surgery groups only. CONCLUSIONS: Continued WL with bariatric surgery is paralleled by favorable changes in eating behavior and food reward and preferences. By contrast, controls experienced weight regain at 1Y follow-up and no changes in eating behavior. These striking differences are likely to be important in the long-term WL management of individuals with severe obesity.

Effects of 3 months of 10-h per-day time-restricted eating and 3 months of follow-up on bodyweight and cardiometabolic health in Danish individuals at high risk of type 2 diabetes: the RESET single-centre, parallel, superiority, open-label, randomised controlled trial.

BACKGROUND: Time-restricted eating (TRE) has been suggested to be a simple, feasible, and effective dietary strategy for individuals with overweight or obesity. We aimed to investigate the effects of 3 months of 10-h per-day TRE and 3 months of follow-up on bodyweight and cardiometabolic risk factors in individuals at high risk of type 2 diabetes. METHODS: This was a single-centre, parallel, superiority, open-label randomised controlled clinical trial conducted at Steno Diabetes Center Copenhagen (Denmark). The inclusion criteria were age 30-70 years with either overweight (ie, BMI ≥25 kg/m2) and concomitant prediabetes (ie, glycated haemoglobin [HbA1c] 39-47 mmol/mol) or obesity (ie, BMI ≥30 kg/m2) with or without prediabetes and a habitual self-reported eating window (eating and drinking [except for water]) of 12 h per day or more every day and of 14 h per day or more at least 1 day per week. Individuals were randomly assigned 1:1 to 3 months of habitual living (hereafter referred to as the control group) or TRE, which was a self-selected 10-h per-day eating window placed between 0600 h and 2000 h. Randomisation was done in blocks varying in size and was open for participants and research staff, but outcome assessors were masked during statistical analyses. The randomisation list was generated by an external statistician. The primary outcome was change in bodyweight, assessed after 3 months (12 weeks) of the intervention and after 3 months (13 weeks) of follow-up. Adverse events were reported and registered at study visits or if participants contacted study staff to report events between visits. This trial is registered on ClinicalTrials.gov (NCT03854656). FINDINGS: Between March 12, 2019, and March 2, 2022, 100 participants (66 [66%] were female and 34 [34%] were male; median age 59 years [IQR 52-65]) were enrolled and randomly assigned (50 to each group). Of those 100, 46 (92%) in the TRE group and 46 (92%) in the control group completed the intervention period. After 3 months of the intervention, there was no difference in bodyweight between the TRE group and the control group (-0·8 kg, 95% CI -1·7 to 0·2; p=0·099). Being in the TRE group was not associated with a lower bodyweight compared with the control group after subsequent 3-month follow-up (-0·2 kg, -1·6 to 1·2). In the per-protocol analysis, participants who completed the intervention in the TRE group lost 1·0 kg (-1·9 to -0·0; p=0·040) bodyweight compared with the control group after 3 months of intervention, which was not maintained after the 3-month follow-up period (-0·4 kg, -1·8 to 1·0). During the trial and follow-up period, one participant in the TRE group reported a severe adverse event: development of a subcutaneous nodule and pain when the arm was in use. This side-effect was evaluated to be related to the trial procedures. INTERPRETATION: 3 months of 10-h per-day TRE did not lead to clinically relevant effects on bodyweight in middle-aged to older individuals at high risk of type 2 diabetes. FUNDING: Novo Nordisk Foundation, Aalborg University, Helsefonden, and Innovation Fund Denmark.

Acute and two-week effects of neotame, stevia rebaudioside M and sucrose-sweetened biscuits on postprandial appetite and endocrine response in adults with overweight/obesity-a randomised crossover trial from the SWEET consortium.

BACKGROUND: Sweeteners and sweetness enhancers (S&SE) are used to replace energy yielding sugars and maintain sweet taste in a wide range of products, but controversy exists about their effects on appetite and endocrine responses in reduced or no added sugar solid foods. The aim of the current study was to evaluate the acute (1 day) and repeated (two-week daily) ingestive effects of 2 S&SE vs. sucrose formulations of biscuit with fruit filling on appetite and endocrine responses in adults with overweight and obesity. METHODS: In a randomised crossover trial, 53 healthy adults (33 female, 20 male) with overweight/obesity in England and France consumed biscuits with fruit filling containing 1) sucrose, or reformulated with either 2) Stevia Rebaudioside M (StRebM) or 3) Neotame daily during three, two-week intervention periods with a two-week washout. The primary outcome was composite appetite score defined as [desire to eat + hunger + (100 - fullness) + prospective consumption]/4. FINDINGS: Each formulation elicited a similar reduction in appetite sensations (3-h postprandial net iAUC). Postprandial insulin (2-h iAUC) was lower after Neotame (95% CI (0.093, 0.166); p < 0.001; d = -0.71) and StRebM (95% CI (0.133, 0.205); p < 0.001; d = -1.01) compared to sucrose, and glucose was lower after StRebM (95% CI (0.023, 0.171); p < 0.05; d = -0.39) but not after Neotame (95% CI (-0.007, 0.145); p = 0.074; d = -0.25) compared to sucrose. There were no differences between S&SE or sucrose formulations on ghrelin, glucagon-like peptide 1 or pancreatic polypeptide iAUCs. No clinically meaningful differences between acute vs. two-weeks of daily consumption were found. INTERPRETATION: In conclusion, biscuits reformulated to replace sugar using StRebM or Neotame showed no differences in appetite or endocrine responses, acutely or after a two-week exposure, but can reduce postprandial insulin and glucose response in adults with overweight or obesity. FUNDING: The present study was funded by the Horizon 2020 program: Sweeteners and sweetness enhancers: Impact on health, obesity, safety and sustainability (acronym: SWEET, grant no: 774293).

Improving the perception of low-light enhanced images.

Improving images captured under low-light conditions has become an important topic in computational color imaging, as it has a wide range of applications. Most current methods are either based on handcrafted features or on end-to-end training of deep neural networks that mostly focus on minimizing some distortion metric -such as PSNR or SSIM- on a set of training images. However, the minimization of distortion metrics does not mean that the results are optimal in terms of perception (i.e. perceptual quality). As an example, the perception-distortion trade-off states that, close to the optimal results, improving distortion results in worsening perception. This means that current low-light image enhancement methods -that focus on distortion minimization- cannot be optimal in the sense of obtaining a good image in terms of perception errors. In this paper, we propose a post-processing approach in which, given the original low-light image and the result of a specific method, we are able to obtain a result that resembles as much as possible that of the original method, but, at the same time, giving an improvement in the perception of the final image. More in detail, our method follows the hypothesis that in order to minimally modify the perception of an input image, any modification should be a combination of a local change in the shading across a scene and a global change in illumination color. We demonstrate the ability of our method quantitatively using perceptual blind image metrics such as BRISQUE, NIQE, or UNIQUE, and through user preference tests.

The association between obesity severity and food reward in adolescents with obesity: a one-stage individual participant data meta-analysis.

BACKGROUND: Food reward and cue reactivity have been linked prospectively to problematic eating behaviours and excess weight gain in adults and children. However, evidence to date in support of an association between degree of adiposity and food reward is tenuous. A non-linear relationship between reward sensitivity and obesity degree has been previously proposed, suggesting a peak is reached in mild obesity and decreases in more severe obesity in a quadratic fashion. OBJECTIVE: To investigate and characterise in detail the relationship between obesity severity, body composition, and explicit and implicit food reward in adolescents with obesity. METHODS: Data from seven clinical trials in adolescents with obesity were aggregated and analysed in an independent participant data meta-analysis. Linear and curvilinear relationships between the degree of obesity and explicit and implicit reward for sweet and high fat foods were tested in fasted and fed states with BMI-z score as a continuous and discrete predictor using clinically recognised partitions. RESULTS: Although positive associations between obesity severity and preference for high-fat (i.e. energy dense) foods were observed when fasted, none reached significance in either analysis. Conversely, adiposity was reliably associated with lower reward for sweet, particularly when measured as implicit wanting (p = 0.012, ηp2 = 0.06), independent of metabolic state. However, this significant association was only observed in the linear model. Fat distribution was consistently associated with explicit and implicit preference for high-fat foods. CONCLUSIONS: A limited relationship was demonstrated between obesity severity and food reward in adolescents, although a lower preference for sweet could be a signal of severe obesity in a linear trend. Obesity is likely a heterogenous condition associated with multiple potential phenotypes, which metrics of body composition may help define. CLINICAL TRIAL REGISTRATIONS: NCT02925572: https://classic. CLINICALTRIALS: gov/ct2/show/NCT02925572 . NCT03807609: https://classic. CLINICALTRIALS: gov/ct2/show/NCT03807609 . NCT03742622: https://classic. CLINICALTRIALS: gov/ct2/show/NCT03742622 . NCT03967782: https://classic. CLINICALTRIALS: gov/ct2/show/NCT03967782 . NCT03968458: https://classic. CLINICALTRIALS: gov/ct2/show/NCT03968458 . NCT04739189: https://classic. CLINICALTRIALS: gov/ct2/show/NCT04739189 . NCT05365685: https://www. CLINICALTRIALS: gov/study/NCT05365685?tab=history .

Post-exercise energy replacement might lead to reduced subsequent energy intake in women with constitutional thinness: Exploratory results from the NUTRILEAN project.

While people with Constitutional Thinness (CT) declare a deep willingness to gain weight, there appetitive responses to energy balance manipulations remain unclear. The present work compares the effect of an acute exercise combined or not with an energy replacement load, on subsequent energy intake, appetite and food reward, between normal weight and women with CT. Anthropometric measurements, body composition (Dual X-ray absorptiometry-DXA) and aerobic capacity (VO2max) were assessed in 10 normal-weight (Body Mass Index-BMI): 20-25 kg/m2) and 10 C T (BMI<17.5 kg/m2) women (18-30 years). They randomly performed i) a resting session (CON); ii) an exercise session (EX); iii) an exercise session with energy replacement (EX + R). Their subsequent ad libitum intake, appetite feelings and food reward were evaluated (Leeds-Food-Preference-Questionnaire). CT showed a lower weight (p < 0,001), BMI(p < 0,001), Fat-Mass (%) (p = 0,003) and Fat-Free Mass (kg) (p < 0,001). CT showed a lower ad libitum energy intake on EX + R compared with CON (p = 0,008) and a higher Relative Energy Intake (REI) on CON compared with EX (p = 0,007) and EX + R (p < 0,001). A lower was observed during EX and EX + R compared with CON (p = 0,006,p = 0,009 respectively) in CT. No condition nor group effect was found for hunger. NW only showed a higher pre-meal fullness on EX + R compared to CON and EX (p < 0,001). Choice (p = 0,030), Explicit Liking (p = 0,016), Explicit Wanting (p = 0,004) and Implicit Wanting (p = 0,035) for taste were higher on EX + R than CON and EX. The decreased EI observed in CT when the exercise-induced energy expenditure is compensated by the ingestion of an equivalent energy load, might contribute to explain the difficulty to increase their energy balance and then induce weight gain. Further studies are needed to better understand their energy balance regulation to propose adapted weight gain strategies.

Can eating behaviour traits be explained by underlying, latent factors? An exploratory and confirmatory factor analysis.

Eating Behaviour Traits (EBTs) are psychological constructs developed to explain patterns of eating behaviour, including factors that motivate people to (over or under) eat. There is a need to align and clarify their unique contributions and harmonise the understanding they offer for human eating behaviour. Therefore, the current study examined whether 18 commonly cited EBTs could be explained by underlying, latent factors (domains of eating behaviour). An exploratory factor analysis (EFA) was used to identify latent factors, and these factors were validated using a confirmatory factor analysis (CFA). 1279 participants including the general public and members of a weight management programme were included in the analysis (957 females, 317 males, 3 others, 2 prefer not to say), with a mean age of 54 years (median = 57 years, SD = 12.03) and a mean BMI of 31.93 kg/m2 (median = 30.86, SD = 6.00). The participants completed 8 questionnaires which included 18 commonly cited EBTs and the dataset was split at random with a 70/30 ratio to conduct the EFA (n = 893) and CFA (n = 383). The results supported a four-factor model which indicated that EBTs can be organised into four domains: reactive, restricted, emotional, and homeostatic eating. The four-factor model also significantly predicted self-reported BMI and weight change. Future research should test whether this factor structure is replicated in more diverse populations, and including other EBTs, to advance these domains of eating as a unifying framework for studying individual differences in human eating behaviour.

Higher energy flux may improve short-term appetite control in adolescents with obesity: the NEXT study.

Recent evidence suggests better appetite control in states of high-energy flux (HEF) in adults and lean children. Nevertheless, it is unknown whether this extends to youth with obesity. This study compares the effects of low, moderate or HEF on short-term appetitive control in adolescents with obesity. Sixteen adolescents with obesity (12-16 years, Tanner stages 3-5, 11 females) randomly completed three conditions: (i) low-energy flux (LEF); (ii) moderate energy flux (MEF; + 250 kcal) and (iii) HEF (HEF; + 500 kcal). Energy flux was achieved in MEF and HEF through elevated energy intake (EI) and concomitant increase in energy expenditure using cycling exercise (65 % VO2peak). Ad libitum EI, macronutrient intake and relative EI were assessed at dinner, subjective appetite sensations taken at regular intervals and food reward measured before dinner. Ad libitum EI at dinner was greater in LEF compared with HEF (P = 0·008), and relative EI (REI) was higher in LEF compared with MEF (P = 0·003) and HEF (P < 0·001). The absolute consumption of carbohydrates was lower in LEF compared with MEF (P = 0·047) and HEF (P < 0·001). Total AUC for hunger and desire to eat was lower in HEF compared with LEF (P < 0·001) and MEF (P = 0·038). Total AUC for prospective food consumption was lower on HEF compared with LEF (P = 0·004). Food choice sweet bias was higher in HEF (P = 0·005) compared with LEF. To conclude, increasing energy flux may improve short-term appetite control in adolescents with obesity.

Can smartphone-based response inhibition training elicit sustained changes in appetite, preference, and cravings for energy-dense foods? A free-living randomized controlled trial.

BACKGROUND: Food-specific response inhibition training has been implemented as a strategy to modify food choices and reward-related eating behaviours, but short-term studies have produced equivocal findings. OBJECTIVE: To longitudinally assess the effect of a smartphone-based response inhibition intervention on food reward, hedonic eating drive, and cravings in a free-living setting. METHODS: 84 adults (Mage = 30.49, SDage = 13.01, 52 female) with high responsivity to food cues or overweight/obesity were randomly assigned to a response inhibition training intervention (n = 45) or a control game (n = 39) at home during a training week, followed by a week with no training. Primary analyses compared groups on measures of explicit liking and implicit wanting for food of different energy densities, food cravings, and reward-related eating throughout this two-week period. RESULTS: A reduction was observed in explicit liking and implicit wanting for energy-dense foods from baseline to post-training independent of condition (ps < .001). These changes from baseline were sustained after a 1-week latency period, also independent of condition (ps < .001). These effects coincided with similar observations of hedonic eating drive, tonic cravings, and control over cravings during the observation period (ps < .01). CONCLUSIONS: Although significant reductions in reward-related appetite were observed, free-living response inhibition training did not offer additional benefit over a control activity. Future intervention studies with observable food intake are needed to investigate which appetitive mechanisms most reliably predict eating behaviour over time. TRIAL REGISTRATION: Retrospectively registered with ANZCTR [ACTRN12622001502729].

Food reward associations with motivational eating behavior traits and body mass index in Portuguese former elite athletes.

BACKGROUND: Motivational eating behavior traits (i.e. eating motivations and intuitive eating) have an important role in body weight regulation, as do food reward processes. Their associations might help explain different responses to food stimulus in the current environment but have never been explored. This study's primary goal was to investigate food reward associations with eating motivations, intuitive eating dimensions and body mass index in former Portuguese elite athletes with overweight/obesity. As a first step, a cultural adaptation of the Leeds Food Preference Questionnaire (LFPQ) was created and validated in an online-surveyed Portuguese sample. RESULTS: Step 1: Analysis from an online survey (N = 348; 69.8% female) conducted to validate the food images from the cultural adaptation of the LFPQ showed that most food images were properly recognized in terms of their fat and sweet content by the Portuguese population, except for some savory items. Step 2: Regarding our primary analysis in 94 former elite athletes with overweight/obesity, self-determined motivations to regulate eating and (to a lower extent) more body-food congruent choices (both markers for healthier eating behaviors) were associated with more favorable food reward outcomes, as opposed to non-self-determined motivations. Less emotional (more intuitive) eaters presented higher implicit wanting for low-fat sweet foods compared to more emotional eaters. CONCLUSION: These findings suggest LFPQ usefulness to evaluate food preferences and detect relevant associations between food reward and motivational eating behavior traits in former elite athletes with overweight/obesity. Health professionals are encouraged to create need-supportive environments that foster self-determined motivations and help individuals make healthier food choices. © 2023 Society of Chemical Industry.

Response inhibition training as an intervention to modify liking and wanting for foods based on energy density: a proof of concept study.

The ubiquity of energy-dense, processed foods has been implicated as a salient feature of the modern 'obesogenic' environment. Cognitive strategies, such as response inhibition training, have been demonstrated to reduce the hedonic value of such foods in previous studies. However, this effect has generally been inconsistent or heterogenous, depending on the outcome measure, characteristics of the sample, and the specificity of food stimuli. Characterising the extent of generalised effects may help define the application of this type of intervention in natural settings. A repeated-measures, proof-of-concept study, using mobile app-based response inhibition training (RIT) versus a control app-based activity (N = 25), was undertaken to establish the valid application of a food reward measure to assess intervention efficacy. Liking (i.e., affect) and wanting (i.e., motivation) for food stimuli categorised by energy density were taken concurrently pre- and post-training. A statistically significant reduction in explicit liking, but not implicit wanting, for foods irrespective of their energy density was observed during the RIT app-based training session relative to the control (p = .041, ηp2 = .16). However, effect sizes associated with devaluation of energy-dense relative to low calorie food stimuli, although non-significant, were higher when measured as implicitly wanting (p = .098, ηp2 = .11) than explicit liking (p = .756, ηp2 = .00). Trends in explicit stimulus evaluations were empirically discordant from implicit evaluations for low calorie foods in particular. Additional research is needed to investigate whether these trends are reproducible with larger samples, trained and novel food stimuli in outcome measures, and more comprehensive training protocols.

Performance Comparison of Classical Methods and Neural Networks for Colour Correction.

Colour correction is the process of converting RAW RGB pixel values of digital cameras to a standard colour space such as CIE XYZ. A range of regression methods including linear, polynomial and root-polynomial least-squares have been deployed. However, in recent years, various neural network (NN) models have also started to appear in the literature as an alternative to classical methods. In the first part of this paper, a leading neural network approach is compared and contrasted with regression methods. We find that, although the neural network model supports improved colour correction compared with simple least-squares regression, it performs less well than the more advanced root-polynomial regression. Moreover, the relative improvement afforded by NNs, compared to linear least-squares, is diminished when the regression methods are adapted to minimise a perceptual colour error. Problematically, unlike linear and root-polynomial regressions, the NN approach is tied to a fixed exposure (and when exposure changes, the afforded colour correction can be quite poor). We explore two solutions that make NNs more exposure-invariant. First, we use data augmentation to train the NN for a range of typical exposures and second, we propose a new NN architecture which, by construction, is exposure-invariant. Finally, we look into how the performance of these algorithms is influenced when models are trained and tested on different datasets. As expected, the performance of all methods drops when tested with completely different datasets. However, we noticed that the regression methods still outperform the NNs in terms of colour correction, even though the relative performance of the regression methods does change based on the train and test datasets.

The energy content of meals with a similar macronutrient distribution may have a greater impact on appetite sensations than food preferences in adolescents with obesity: A secondary analysis.

PURPOSE: The energy and macronutrient composition of a meal has been shown to influence postprandial appetitive responses, but it is not clear how energy content independent of macronutrient distribution affects postprandial appetite in adolescents with obesity. Extracting data from a primary study testing the effect of energy turnover on appetite, this secondary analysis assessed how fixed meals varying in energy content with similar macronutrient distributions influences postprandial appetite sensations and food reward. METHODS: Using a randomised, counterbalanced crossover design, N = 14 adolescents with obesity (Mage = 12.71, SDage = 0.99; 10 female) consumed fixed lunch meals with similar macronutrient content starting at 750 kcal in energy and progressively increasing by 250 kcal on three different test days. Liking and wanting for food images varying in fat and taste were assessed at baseline and immediately after meal consumption. Appetite sensations were assessed in half-hour intervals from baseline to 1-h post-meal. RESULTS: The area under the curve for subjective hunger (p < .001, ω = 0.36), desire to eat (p < .001, ω = 0.54), and prospective food consumption (p = .004, ω = 0.32) were significantly lower after consumption of the higher calorie meals relative to the lowest. Explicit wanting for sweet foods increased after intake of the intermediate calorie meal yet decreased after the highest calorie meal (p = .014, ω = 0.09). Conversely, implicit wanting sweet bias increased after consumption of the test meal independent of energy content (p < .001, ω = 0.15). CONCLUSION: The consumption of additional calories without a meaningful change in macronutrient distribution may affect appetite sensations more reliably than hedonic responses to energy-dense foods in adolescents with obesity.

Diet composition and energy intake in humans.

Absolute energy from fats and carbohydrates and the proportion of carbohydrates in the food supply have increased over 50 years. Dietary energy density (ED) is primarily decreased by the water and increased by the fat content of foods. Protein, carbohydrates and fat exert different effects on satiety or energy intake (EI) in the order protein > carbohydrates > fat. When the ED of different foods is equalized the differences between fat and carbohydrates are modest. Covertly increasing dietary ED with fat, carbohydrate or mixed macronutrients elevates EI, producing weight gain and vice versa. In more naturalistic situations where learning cues are intact, there appears to be greater compensation for the different ED of foods. There is considerable individual variability in response. Macronutrient-specific negative feedback models of EI regulation have limited capacity to explain how availability of cheap, highly palatable, readily assimilated, energy-dense foods lead to obesity in modern environments. Neuropsychological constructs including food reward (liking, wanting and learning), reactive and reflective decision making, in the context of asymmetric energy balance regulation, give more comprehensive explanations of how environmental superabundance of foods containing mixtures of readily assimilated fats and carbohydrates and caloric beverages elevate EI through combined hedonic, affective, cognitive and physiological mechanisms. This article is part of a discussion meeting issue 'Causes of obesity: theories, conjectures and evidence (Part II)'.

No effect of prefrontal transcranial direct current stimulation (tDCS) on food craving, food reward and subjective appetite in females displaying mild-to-moderate binge-type behaviour.

Previous work suggests there may be an effect of transcranial direct current stimulation (tDCS) on appetite control in people at risk of overconsumption, however findings are inconsistent. This study aimed to further understand the potential eating behaviour trait-dependent effect of tDCS, specifically in those with binge-type behaviour. Seventeen females (23 ± 7 years, 25.4 ± 3.8 kg m-2) with mild-to-moderate binge eating behaviour completed two sessions of double-blind, randomised and counterbalanced anodal and sham tDCS applied over the right dorsolateral prefrontal cortex at 2.0 mA for 20 min. Subjective appetite visual analogue scales (VAS), the Food Craving Questionnaire-State (FCQ-S), and Leeds Food Preference Questionnaire (LFPQ) were completed pre- and post-tDCS. Participants then consumed a fixed-energy meal, followed by the VAS, FCQ-S and LFPQ. No difference between pre- and post-tDCS scores were found across fullness (p = 0.275, BF10 = 0.040), prospective consumption (p = 0.127, BF10 = 0.063), desire to eat (p = 0.247, BF10 = 0.054) or FCQ-S measures (p = 0.918, BF10 = 0.040) when comparing active and sham protocols. Only explicit liking and wanting for high-fat sweet foods were significantly different between conditions, with increased scores following active tDCS. When controlling for baseline hunger, the significant differences were removed (p = 0.138 to 0.161, BF10 = 0.810 to 1.074). The present data does not support the eating behaviour trait dependency of tDCS in a specific cohort of female participants with mild-to-moderate binge eating scores, and results align with those from individuals with healthy trait scores. This suggests participants with sub-clinical binge eating behaviour do not respond to tDCS. Future work should further explore effects in clinical and sub-clinical populations displaying susceptibility to overconsumption and weight gain.

Exploratory analysis of reflective, reactive, and homeostatic eating behaviour traits on weight change during the 18-month NoHoW weight maintenance trial.

Behaviour change interventions for weight management have found varied effect sizes and frequent weight re-gain after weight loss. There is interest in exploring whether differences in eating behaviour can be used to develop tailored weight management programs. This secondary analysis of an 18-month weight maintenance randomised controlled trial (RCT) aimed to investigate the association between individual variability in weight maintenance success and change in eating behaviour traits (EBT). Data was analysed from the NoHoW trial (Scott et al., 2019), which was designed to measure processes of change after weight loss of ≥5% body weight in the previous year. The sample included 1627 participants (mean age = 44.0 years, SD = 11.9, mean body mass index (BMI) = 29.7 kg/m2, SD = 5.4, gender = 68.7% women/31.3% men). Measurements of weight (kg) and 7 EBTs belonging to domains of reflective, reactive, or homeostatic eating were taken at 4 time points up to 18-months. Increases in measures of 'reactive eating' (binge eating, p < .001), decreases in 'reflective eating' (restraint, p < .001) and changes in 'homeostatic eating' (unlimited permission to eat, p < .001 and reliance on hunger and satiety cues, p < .05) were significantly and independently associated with concomitant weight change. Differences in EBT change were observed between participants who lost, maintained, or re-gained weight for all EBTs (p < .001) except for one subscale of intuitive eating (eating for physical reasons, p = .715). Participants who lost weight (n = 322) exhibited lower levels of reactive eating and higher levels of reflective eating than participants who re-gained weight (n = 668). EBT domains can identify individuals who need greater support to progress in weight management interventions. Increasing reflective eating and reducing reactive eating may enhance weight management success.