BACKGROUND/OBJECTIVES:Neurobiological frameworks of obesity in youth have focused largely on non-homeostatic systems (reward, salience, executive control), while the homeostatic system-particularly the hypothalamus-is comparatively understudied. A clearer picture of how these systems interact in adolescents with severe obesity is needed to inform treatment. This study sought to test whether adolescents with severe obesity exhibit altered hypothalamic functional connectivity, relative to healthy-weight peers, across fasting and fed states. SUBJECTS/METHODS:We analyzed data from the Food and Adolescent Brain Study, a single-blinded randomized cross-over trial (NCT04208256) of 13-18-year-old adolescents with severe obesity (SO; body mass index [BMI] >99th %ile; n = 30; mean [SD] age 14.6 years [1.5]) and with healthy weight (HW; BMI <85th %ile; n = 26; 15.5 years [1.6]). INTERVENTIONS/METHODS:Participants completed resting-state functional magnetic resonance scans during fasting and after ingesting a 75-gram glucose drink (1 255.8 kJ [300 kcal]) to induce a fed state. Multivariate general linear models were run in seed-to-voxel analyses to estimate functional connectivity, setting the hypothalamus as the seed region. All models were adjusted for sex and household income with significance determined via cluster-forming voxel-level p < 0.005 and false discovery rate-corrected cluster-level p < 0.05. RESULTS:In adolescents with SO, during fasting, hypothalamic connectivity was weaker to the bilateral cerebellum and left(L) middle occipital gyrus, and stronger to the right(R) postcentral/supramarginal gyri, compared to the HW group. During the fed state, hypothalamic connectivity increased to the bilateral middle frontal gyri and R putamen and decreased to the R caudate and L superior frontal gyrus in adolescents with SO, relative to the HW group. CONCLUSION:Severe obesity in adolescence is associated with altered communication between homeostatic (hypothalamus) and non-homeostatic brain structures, evident across fasting and fed states. Findings underscore the need to incorporate homeostatic circuitry into pediatric obesity frameworks.

There is growing interest in the role of large portions in overeating. Experimental studies consistently demonstrate that serving large amounts of food leads individuals to consume more food and energy than they require. This portion size effect has been observed across different types of foods and beverages and can be sustained over several months. Furthermore, there is evidence that prolonged provision of large portions can lead to weight gain. The robust nature of this effect has led to efforts to identify strategies to manage food and beverage portions. Certain characteristics of the consumer (e.g., satiety responsiveness, slowness of eating) and the available food (e.g., relative palatability, value) have been found to influence the effect of portion size, and these are potential targets for interventions to attenuate the response. To date, the most reliable and effective method to moderate energy intake from large portions is reducing the energy density of the diet. Future studies need to build on current knowledge to understand individual and contextual variability in the response to portion size. A more comprehensive understanding of the portion size effect can lead to the development of a systems approach in which the food, individual, and environment are targeted simultaneously to counter the effects of large portions.

Research in adults has shown that food form (e.g., liquid, semi-solid, solid) influences satiety, even when energy and energy density are matched. However, less is known about the impact of food form on satiety in children. We examined the influence of food form on children's subsequent meal intake. Children (n = 64, F = 32; mean age 5.9 years-old) completed a crossover study with 5 laboratory visits, each ∼1 week apart. During each visit, children were presented with no preload (control) or one of 4 apple preloads: slices, purée, juice, or juice sweetened with non-nutritive sweetener. Apple slices, purée, and juice were matched for energy and energy density. Visual cues were masked and eating rate was controlled. The order of conditions was pseudorandomized and counterbalanced. Following the preload, children ate ad libitum from a standardized meal and satiety was calculated as the % of energy intake at the preload + meal relative to intake at the no preload condition (100 % = perfect compensation). Food form did not influence satiety. Satiety was 112 %, 121 %, and 120 % for apple slices, purée, and juice, respectively (p > 0.05). Results, however, varied by sex: boys showed near perfect (99 %) compensation for apple slices (p < 0.01), while it was 125 % in girls. Compared to the control condition, satiety in boys was better (i.e., closer to 100 %) than in girls (p < 0.05). Thus, when visual cues were masked and consumption rate controlled, solid fruit and fruit juice had similar effects on satiety, but across fruit forms, boys showed better satiety than girls. These findings suggest that factors that influence satiety differ by child sex; we posit that satiety in girls may be driven more by social/learned cues while boys respond to biological signals.

Switching between different foods while eating has been positively associated with weight status and intake in children. Evidence suggests that switching behavior is consistent within children across meals, however, it is unclear how switching relates to changes in adiposity over time. In a 1-year longitudinal study, we assessed whether food switching predicted changes in fat mass index (FMI: fat mass kg/height m2) in 7-8-year-old children and tested if familial risk of obesity moderated this relationship. At baseline, seventy-four children without obesity (7.8 ± 0.6 y; 37F) consumed four ad libitum meals of varying portion sizes, each consisting of chicken nuggets, macaroni and cheese, grapes, and broccoli. For each child, the average number of food switches was calculated from video recordings across the four meals. To assess change in adiposity over time, children completed a dual energy x-ray absorptiometry scan for assessment of FMI at baseline and follow-up (≥1 year later). Familial risk of obesity was determined by maternal BMI (high-risk: ≥30 kg/m2, n = 32 vs. low-risk: <25 kg/m2, n = 42). Food switching at baseline was positively associated with changes in FMI over 1 year (p = 0.03). In addition to the 37% of variance in FMI change explained by known factors influencing adiposity, food switching accounted for an additional 4% of the variance (p = 0.03). Further, there was an interaction between familial risk status and food switching (p = 0.04) such that the relationship between switching and FMI change was only significant in high-risk children. Overall, children's food switching behavior assessed at laboratory meals predicted change in adiposity over 1 year. Food switching could be a behavioral marker for, and contribute to, pediatric obesity risk particularly in children with a familial predisposition.

Food variety promotes intake, and the propensity to seek a greater variety, measured by the number of unique foods selected for a meal, may predict increased food consumption. We explored whether variety-seeking in a validated immersive virtual reality (iVR) food buffet was related to measured intake in lab meals. Adults (n = 91; 18-71y; 64 female) were asked to select foods for a meal in an iVR buffet before consuming a standard lab meal once a week for 2 weeks. The iVR buffet contained 30 foods, 15 lower energy-dense (LED) and 15 higher energy-dense (HED), including entrees, sides, soups, and desserts. The lab meal consisted of 3 LED foods (broccoli, grapes, chicken) and 3 HED foods (pasta, rolls, cookies). Food selection in the iVR buffet was operationalized into 3 variety-seeking behavioral markers based on the unique foods selected: (1) total, (2) HED, and (3) LED. Seeking a greater total variety in iVR was a significant predictor of intake in lab meals, with each additional unique food selected in iVR relating to an additional 7.4 g of food consumed in lab meals (p = 0.01). These associations demonstrate specificity: (1) seeking a greater variety of HED foods in iVR was associated with increased intake of HED foods in lab meals, and (2) seeking a greater variety of LED foods in iVR was associated with increased intake of LED foods in lab meals. These preliminary findings indicate that variety-seeking behavioral markers measured in an iVR buffet are related to measured food intake.

Innovative methods are needed to understand associations between food selection and intake across different contexts. We explored whether the energy density (ED, kilocalories per gram) of meals selected in an immersive virtual reality (iVR) food buffet predicted the ED consumed and overall energy intake in measured laboratory meals. In a secondary analysis, 91 adults (64 female, aged 18 to 71 years) selected foods for a meal in our iVR buffet before consuming a standard laboratory meal once a week for two weeks. The iVR buffet contained 30 foods varying in ED, ranging from 0.3 to 4.9 kcal per gram, including entrees, sides, soups, and desserts. The laboratory meals consisted of pasta, rolls, chicken, broccoli, grapes, and cookies, with ED values ranging from 0.4 to 4.8 kcal per gram. Linear mixed-effect models were used to examine associations between food selections in iVR meals and intake in laboratory meals. We found that the ED selected in iVR significantly predicted the ED consumed in laboratory meals. The ED consumed in laboratory meals and the ED selected in IVR meals were both positively associated with energy intake in laboratory meals. In addition, the carbohydrates, fats, and protein selected in iVR meals were each significantly associated with their respective intake in laboratory meals. The significant associations between food selections in iVR meals and intake in laboratory meals demonstrate the predictive validity of iVR. These findings highlight the utility of iVR as an innovative method to assess associations between food selection and intake across diverse contexts.

Much of the interest in studying human eating behavior stems from a desire to characterize properties of foods that affect consumption, with the goal of leveraging influential properties to moderate energy intake. We propose that established determinants of intake include "The Big Three": portion size, energy density, and variety. Over the past several decades, multiple studies have demonstrated a causal relationship between portion size and intake across different participants, settings, and contexts. The robust effect of portion size can be leveraged to moderate intake by increasing the proportion of low-energy-dense dietary components available. Among "The Big Three", energy density likely plays the most dominant role. Even small reductions in energy density, such as increasing the water content of foods, can lead to reductions in energy intake, and, over time, body weight. In addition, increased food variety can delay satiation by countering the relative hedonic decline of a food as it is consumed (sensory-specific satiety). As a result, exposure to a greater variety of foods increases intake, especially when the sensory properties of the foods served differ from one another. "The Big Three" characterize the current food environment, which is filled with a wide variety of food options, many of which are energy-dense and large in portion size. This review covers early studies assessing the effects of these three food properties on satiation, introduces recent studies, and discusses how this understanding can be applied to moderating energy intake.

Effects of food properties on satiety can be evaluated by having individuals consume a compulsory first-course preload before an ad libitum test meal. One measure of satiety is energy compensation, which can be quantified as total meal energy intake (preload + test meal) expressed as a percentage of an individual's energy intake at a no-preload control meal. In this secondary analysis, we evaluated characteristics of preloads, test meals, and participants that predict energy compensation, in order to inform methods for satiety assessment. We combined data from 13 preloading studies comprising weighed intakes from 1757 preload meals across 511 participants. The results showed that energy compensation was positively influenced by preload energy and energy density, and negatively influenced by preload weight (all p < 0.0001). Energy compensation was not, however, affected by characteristics of the test meal or the participants. The strongest predictor of energy compensation was the energy content of the preload relative to an individual's control meal energy intake, which explained 32 % of the variability in the outcome. Complete energy compensation was observed when preload energy averaged 27 % of control meal intake. The finding that relative preload energy was the strongest predictor of compensation underscores the importance of including a control condition in preloading studies. This allows researchers to focus on the effects of preload properties by adjusting for any influential characteristics of the test meal and participants. Understanding predictors of energy compensation can be used to improve methods for satiety assessment and to facilitate interpretation of findings from preloading studies.

Background: Behavioral phenotypes that predict future weight gain are needed to identify children susceptible to obesity. Objectives: This prospective study developed an eating behavior risk score to predict change in adiposity over 1 y in children. Methods: Data from 6 baseline visits (Time 1, T1) and a 1-y follow-up visit (Time 2, T2) were collected from 76, 7- to 8-y-old healthy children recruited from Central Pennsylvania. At T1, children had body mass index (BMI) percentiles < 90 and were classi fi ed with either high ( n = 33; maternal BMI >= 30 kg/m (2) ) or low ( n = 43; maternal BMI < 25 kg/m (2) ) familial risk for obesity. Appetitive traits and eating behaviors were assessed at T1. Adiposity was measured at T1 and T2 using dual-energy x-ray absorptiometry, with a main outcome of fat mass index (FMI; total body fat mass divided by height in meters squared). Hierarchical linear regressions determined which eating measures improved prediction of T2 FMI after adjustment for covariates in the baseline model (T1 FMI, sex, income, familial risk, and Tanner stage). Results: Four eating measures - Portion susceptibility, Appetitive traits, loss of control eating, and eating rate - were combined into a standardized summary score called PACE. PACE improved the baseline model to predict 80% variance in T2 FMI. PACE was positively associated with the increase in FMI in children from T1 to T2, independent of familial risk ( r = 0.58, P < 0.001). Although PACE was higher in girls than boys ( P < 0.05), it did not differ by familial risk, income, or education. Conclusions: PACE represents a cumulative eating behavior risk score that predicts adiposity gain over 1 y in middle childhood. If PACE similarly predicts adiposity gain in a cohort with greater racial and socioeconomic diversity, it will inform the development of interventions to prevent obesity. This trial was registered at clinicaltrials.gov as NCT03341247.

Emerging evidence suggests switching between foods during an eating event is positively associated with intake. However, it is unclear whether switching is a stable behavior that predicts consumption across multiple eating events. The current study explored whether switching is consistent within children and reliably associated with intake across varied eating events. We analyzed data from 88 (45 F), 7 -8 -year -old children without obesity participating in a 7 -visit prospective cohort study (ClinicalTrials.gov NCT03341247). Amount consumed and energy intake were measured at 4 separate meals of foods that varied by portion sizes served. Meals included macaroni and cheese, chicken nuggets, broccoli, and grapes (all 0.7 -2.5 kcal/g). Children 's intake was also assessed during 2 eating in the absence of hunger (EAH) paradigms separated by >= 1 year. The EAH paradigm included 9 sweet and savory snack foods (all 1.9 -5.7 kcal/g). All eating events were video -recorded and switching was assessed by counting the number of times a child shifted between different food items. Results demonstrated that switching was reliably associated with intake at both the meals and the EAH paradigms (ps < 0.01). Specifically, at meals each additional switch was associated with 11.7 +/- 1.3 kcal (7.7 +/- 0.8 g) more consumed, and during EAH each additional switch was associated with 8.1 +/- 2.1 kcal (2.1 +/- 0.5 g) more consumed. Switching behavior was also moderately consistent across meals (ICC = 0.70) and EAH paradigms (ICC = 0.50). However, switching at meals was not related to switching at EAH paradigms. This study demonstrates the consistency of switching behavior and its reliable association with intake across eating events, highlighting its potential to contribute to chronic overconsumption and childhood obesity.

Processed foods have been part of the American diet for decades, with key roles in providing a safe, available, affordable, and nutritious food supply. The USDA Food Guides beginning in 1916 and the US Dietary Guidelines for Americans (DGA) since 1980 have included various types of commonly consumed processed foods (e.g., heated, fermented, dried) as part of their recommendations. However, there are multiple classification systems based on “level” of food processing, and additional evidence is needed to establish the specific properties of foods classified as “highly” or “ultra”-processed (HPF/UPFs). Importantly, many foods are captured under HPF/UPF definitions, ranging from ready-to-eat fortified whole grain breakfast cereals to sugar-sweetened beverages and baked goods. The consequences of implementing dietary guidance to limit all intake of foods currently classified as HPF/UPF may require additional scrutiny to evaluate the impact on consumers’ ability to meet daily nutrient recommendations and to access affordable food, and ultimately, on health outcomes. Based on a meeting held by the Institute for the Advancement of Food and Nutrition Sciences in May 2023, this paper provides perspectives on the broad array of foods classified as HPF/UPFs based on processing and formulation, including contributions to nutrient intake and dietary patterns, food acceptability, and cost. Characteristics of foods classified as UPF/HPFs are considered, including the roles and safety approval of food additives and the effect of food processing on the food matrix. Finally, this paper identifies information gaps and research needs to better understand how the processing of food affects nutrition and health outcomes.

BACKGROUND:Eating in the absence of hunger (EAH) is a behavioral phenotype of pediatric obesity characterized by the consumption of palatable foods beyond hunger. Studies in children have identified EAH to be stable over time, but findings are unclear on whether it predicts the development of adiposity, particularly in middle childhood, a period of increased autonomy over food choices. OBJECTIVES:We hypothesized that EAH would remain stable and be associated with increased adiposity over a ≥1-y prospective study in 7-8-y old children without obesity. Secondary hypotheses tested whether physical activity moderated the impact of EAH on adiposity. METHODS:Children (n =72, age 7.8 ± 0.6 y; BMI% <90th), in a 7-visit longitudinal study, had EAH, adiposity, and physical activity assessed at baseline (time 1 - T1) and follow-up (time 2 - T2). EAH was determined by measuring children's intake from 9 energy-dense (>3.9 kcal/g) sweet and savory foods during a 10-min access period after intake of a standard meal eaten to satiation. Adiposity was measured by dual-energy X-ray absorptiometry (DXA), with an outcome of fat mass index (FMI; fat mass/height in m2). Seven days of wrist-worn Actigraphy quantified moderate-to-vigorous-physical activity (MVPA) and sedentary time. RESULTS:EAH had moderate stability across time points (ICC = 0.54). ICCs were stronger for sweet (ICC = 0.53) than savory (ICC = 0.38) foods. Linear regression predicting 1-y change in FMI (adjusted for income, parent education, sex, time to follow-up, T2 Tanner stage, maternal weight status, and baseline adiposity) found that both total and sweet food EAH at baseline predicted increases in adiposity (P < 0.05 for both). EAH and adiposity were negatively correlated among children with high MVPA and low sedentary time. CONCLUSIONS:These findings show that EAH is a stable predictive phenotype of increases in adiposity over 1 y among youth in middle childhood, although activity-related behaviors may moderate this effect. If replicated, targeting EAH as part of interventions may prevent excess adiposity gain. TRIAL REGISTRATION NUMBER:The data was obtained from the Food and Brain study with registration number: NCT03341247.

Prior studies evaluating a single meal in children characterized an "obesogenic" style of eating marked by larger bites and faster eating. It is unclear if this style is consistent across portion sizes within children so we examined eating behaviors in 91 children (7-8 years, 45 F) without obesity (BMI<90th percentile). Children consumed 4 ad libitum meals in the laboratory consisting of chicken nuggets, macaroni, grapes, and broccoli that varied in portion size (100%, 133%, 166%, 200%) with a maximum of 30 min allotted per meal. Anthropometrics were assessed using age and sex adjusted body mass index (BMI) percentile and dual energy x-ray absorptiometry. Bites, sips, active eating time, and meal duration were coded from meal videos; bite size (kcal and g/bite), proportion of active eating (active eating time/meal duration), and eating rate (kcal and g/meal duration) were computed. Intraclass correlation coefficients (ICC) showed that most eating behaviors were moderately consistent across portions (>0.50). The consistency of associations between eating behaviors and total meal intake and adiposity were assessed with general linear models adjusted for food liking, pre-meal fullness, age, and sex. Across all portions, more bites, faster eating rate, and longer meal duration were associated with greater intake. While higher BMI percentile was associated with faster eating rates across all meals, greater fat mass index was only associated with faster eating at meals with portions typical for children (i.e., 100% and 133%). In a primarily healthy weight sample, an 'obesogenic' style of eating was a consistent predictor of greater intake across meals that varied in portion size. The consistent relationship of these behaviors with intake makes them promising targets to reduce overconsumption.

Individuals eat more food when larger portions are served, and this portion size effect could be influenced by inhibitory control (the ability to suppress an automatic response). Inhibitory control may also relate to obesogenic meal behaviors such as eating faster, taking larger bites, and frequent switching between meal components (such as bites of food and sips of water). In a randomized crossover design, 44 adults ate lunch four times in the laboratory. Lunch consisted of a pasta dish that was varied in portion size (400, 500, 600, or 700 g) along with 700 g of water. Meals were video-recorded to assess meal duration and bite and sip counts, which were used to determine mean eating rate (g/min), mean bite size (g/bite), and number of switches between bites and sips. Participants completed a food-specific stop-signal task, which was used to calculate Stop-Signal Reaction Time (SSRT). Across participants, SSRT values ranged from 143 to 306 msec, where greater SSRT indicates poorer inhibitory control. As expected, serving larger portions increased meal intake (p < 0.0001); compared to the smallest portion, intake of the largest increased by 121 ± 17 g (mean ± SEM). SSRT did not moderate the portion size effect (p = 0.34), but individuals with poorer inhibitory control ate more across all meals: 24 ± 11 g for each one SD unit increase in SSRT (p = 0.035). SSRT was not related to eating rate or bite size (both p > 0.13), but poorer inhibitory control predicted greater switching between bites and sips, such that 1.5 ± 0.7 more switches were made during meals for each one SD unit increase in SSRT (p = 0.03). These findings indicate that inhibitory control can contribute to overconsumption across meals varying in portion size, potentially in part by promoting switching behavior.

Overeating associated with neurogenic obesity after spinal cord injury (SCI) may be related to how persons with SCI experience satiation (processes leading to meal termination), their eating frequency, and the context in which they eat their meals. In an online, cross-sectional study, adults with (n = 688) and without (Controls; n = 420) SCI completed the Reasons Individuals Stop Eating Questionnaire-15 (RISE-Q-15), which measures individual differences in the experience of factors contributing to meal termination on five scales: Physical Satisfaction, Planned Amount, Decreased Food Appeal, Self-Consciousness, and Decreased Priority of Eating. Participants also reported weekly meal and snack frequency and who prepares, serves, and eats dinner with them at a typical dinner meal. Analysis revealed that while Physical Satisfaction, Planned Amount, and Decreased Food Appeal were reported as the most frequent drivers of meal termination in both groups, scores for the RISE-Q-15 scales differed across the groups. Compared to Controls, persons with SCI reported Physical Satisfaction and Planned Amount as drivers of meal termination less frequently, and Decreased Food Appeal and Decreased Priority of Eating more frequently (all p < 0.001). This suggests that persons with SCI rely less on physiological satiation cues for meal termination than Controls and instead rely more on hedonic cues. Compared to Controls, persons with SCI less frequently reported preparing and serving dinner meals and less frequently reported eating alone (all p < 0.001), indicating differences in meal contexts between groups. Individuals with SCI reported consuming fewer meals than Controls but reported a higher overall eating frequency due to increased snacking (p ≤ 0.015). A decrease in the experience of physical fullness, along with a dependence on a communal meal context and frequent snacking, likely contribute to overeating associated with neurogenic obesity after SCI.