New insights in the mechanisms of weight-loss maintenance: Summary from a Pennington symposium.

Obesity is a chronic disease that affects more than 650 million adults worldwide. Obesity not only is a significant health concern on its own, but predisposes to cardiometabolic comorbidities, including coronary heart disease, dyslipidemia, hypertension, type 2 diabetes, and some cancers. Lifestyle interventions effectively promote weight loss of 5% to 10%, and pharmacological and surgical interventions even more, with some novel approved drugs inducing up to an average of 25% weight loss. Yet, maintaining weight loss over the long-term remains extremely challenging, and subsequent weight gain is typical. The mechanisms underlying weight regain remain to be fully elucidated. The purpose of this Pennington Biomedical Scientific Symposium was to review and highlight the complex interplay between the physiological, behavioral, and environmental systems controlling energy intake and expenditure. Each of these contributions were further discussed in the context of weight-loss maintenance, and systems-level viewpoints were highlighted to interpret gaps in current approaches. The invited speakers built upon the science of obesity and weight loss to collectively propose future research directions that will aid in revealing the complicated mechanisms involved in the weight-reduced state.

Momentary Influences on Self-Regulation in Two Populations With Health Risk Behaviors: Adults Who Smoke and Adults Who Are Overweight and Have Binge-Eating Disorder.

Introduction: Self-regulation has been implicated in health risk behaviors and is a target of many health behavior interventions. Despite most prior research focusing on self-regulation as an individual-level trait, we hypothesize that self-regulation is a time-varying mechanism of health and risk behavior that may be influenced by momentary contexts to a substantial degree. Because most health behaviors (e.g., eating, drinking, smoking) occur in the context of everyday activities, digital technologies may help us better understand and influence these behaviors in real time. Using a momentary self-regulation measure, the current study (which was part of a larger multi-year research project on the science of behavior change) used ecological momentary assessment (EMA) to assess if self-regulation can be engaged and manipulated on a momentary basis in naturalistic, non-laboratory settings. Methods: This one-arm, open-label exploratory study prospectively collected momentary data for 14 days from 104 participants who smoked regularly and 81 participants who were overweight and had binge-eating disorder. Four times per day, participants were queried about momentary self-regulation, emotional state, and social and environmental context; recent smoking and exposure to smoking cues (smoking sample only); and recent eating, binge eating, and exposure to binge-eating cues (binge-eating sample only). This study used a novel, momentary self-regulation measure comprised of four subscales: momentary perseverance, momentary sensation seeking, momentary self-judgment, and momentary mindfulness. Participants were also instructed to engage with Laddr, a mobile application that provides evidence-based health behavior change tools via an integrated platform. The association between momentary context and momentary self-regulation was explored via mixed-effects models. Exploratory assessments of whether recent Laddr use (defined as use within 12 h of momentary responses) modified the association between momentary context and momentary self-regulation were performed via mixed-effects models. Results: Participants (mean age 35.2; 78% female) in the smoking and binge-eating samples contributed a total of 3,233 and 3,481 momentary questionnaires, respectively. Momentary self-regulation subscales were associated with several momentary contexts, in the combined as well as smoking and binge-eating samples. For example, in the combined sample momentary perseverance was associated with location, positively associated with positive affect, and negatively associated with negative affect, stress, and tiredness. In the smoking sample, momentary perseverance was positively associated with momentary difficulty in accessing cigarettes, caffeine intake, and momentary restraint in smoking, and negatively associated with temptation and urge to smoke. In the binge-eating sample, momentary perseverance was positively associated with difficulty in accessing food and restraint in eating, and negatively associated with urge to binge eat. While recent Laddr use was not associated directly with momentary self-regulation subscales, it did modify several of the contextual associations, including challenging contexts. Conclusions: Overall, this study provides preliminary evidence that momentary self-regulation may vary in response to differing momentary contexts in samples from two exemplar populations with risk behaviors. In addition, the Laddr application may modify some of these relationships. These findings demonstrate the possibility of measuring momentary self-regulation in a trans-diagnostic way and assessing the effects of momentary, mobile interventions in context. Health behavior change interventions may consider measuring and targeting momentary self-regulation in addition to trait-level self-regulation to better understand and improve health risk behaviors. This work will be used to inform a later stage of research focused on assessing the transdiagnostic mediating effect of momentary self-regulation on medical regimen adherence and health outcomes. Clinical Trial Registration: ClinicalTrials.gov, Identifier: NCT03352713.

Commentary on: "What is restrained eating and how do we identify it?": Unveiling the elephant in the room.

This paper is a commentary on Polivy, Herman and Mills' (2020) article, entitled "What is restrained eating and how do we identify it?". Polivy et al.'s paper makes a useful contribution by providing guidelines to researchers for choosing the most appropriate measure of restraint for their research questions. However, the authors assume that restrained eating can be appropriately conceptualized as a trait, an assumption I question. They also assume that restrained eating has a causal influence on the outcomes (e.g., counterregulatory eating, negative affect eating, binge eating) with which it has been associated, which I also question. Finally, they ignored a second prominent model for conceptualizing dieting behavior, the Three-Factor Model of Dieting. The Three-Factor Model decomposes the construct of restrained eating into two types of dieting (current weight loss dieting and weight suppression) that do appear to be causally related to eating control and one type (restrained eating to avoid excessive consumption) that modulates likelihood of overeating but does not cause it. I conclude by noting that scientific progress is best served by promoting, not avoiding, discussion and debate about a multiplicity of perspectives on topics of interest, especially when incompatible hypotheses and data exist on such topics.

Describing the Weight-Reduced State: Physiology, Behavior, and Interventions.

Although many persons with obesity can lose weight by lifestyle (diet and physical activity) therapy, successful long-term weight loss is difficult to achieve, and most people who lose weight regain their lost weight over time. The neurohormonal, physiological, and behavioral factors that promote weight recidivism are unclear and complex. The National Institute of Diabetes and Digestive and Kidney Diseases convened a workshop in June 2019, titled "The Physiology of the Weight-Reduced State," to explore the mechanisms and integrative physiology of adaptations in appetite, energy expenditure, and thermogenesis that occur in the weight-reduced state and that may oppose weight-loss maintenance. The proceedings from the first session of this workshop are presented here. Drs. Michael Rosenbaum, Kevin Hall, and Rudolph Leibel discussed the physiological factors that contribute to weight regain; Dr. Michael Lowe discussed the biobehavioral issues involved in weight-loss maintenance; Dr. John Jakicic discussed the influence of physical activity on long-term weight-loss maintenance; and Dr. Louis Aronne discussed the ability of drug therapy to maintain weight loss.

Implicit Mental Motor Imagery Task Demonstrates a Distortion of the Body Schema in Patients With Eating Disorders.

OBJECTIVES: A rich body of literature has established the role of body image distortion and dissatisfaction in the development and maintenance of eating disorders. However, many of the currently used techniques require explicit comparison of the person's body to an external stimulus. As the body schema is a largely unconscious construct, explicit comparison tasks may reflect a proxy, rather than the body schema itself. METHODS: Here we use an implicit mental motor imagery (MMI) task to interrogate the body schema in healthy control participants (N=40) and participants at a residential eating disorder treatment center (N=42). By comparing the time it takes to imagine making a movement along a part of the body to the time it takes to actually make the same movement, we were able to assess participants' mental image of their body (i.e., body schema). RESULTS: We found that participants with eating disorders, but not healthy controls, exhibited distortions of the body schema such that they believed their abdomen, buttocks, and thighs to be larger than they really are. Additionally, the MMI task used here provided information above and beyond traditional self-report measures (i.e., Body Shape Questionnaire). Together the MMI task and traditional measures provide the most information. CONCLUSIONS: Findings using the novel MMI task are in line with the literature; participants with eating disorders consider themselves to be larger than they truly are. Taken together, results of this study suggest that MMI tasks provide complementary information to traditional self-report measures. (JINS, 2018, 24, 715-723).

Eating in the absence of hunger is related to loss-of-control eating, hedonic hunger, and short-term weight gain in normal-weight women.

Eating beyond physiological need contributes to obesity onset. Measuring this behavior could help identify those at risk for weight gain. This study measured eating in the absence of hunger (EAH) and its relationship with weight change and self-report measures related to appetite and eating behavior. EAH was assessed in 46 lean young women (69% pre-selected for weight gain proneness) after lunch and defined as the number of calories subsequently consumed from snacks. Participants also completed questionnaires, and their body weights were measured regularly over the next year. Participants consumed a mean 188 calories (±140) during the EAH test. Caloric intake during the EAH test was associated with hedonic hunger (p < .01, R2 = 0.18), loss of control eating (p < .001, R2 = 0.29), and weight gain over two months (p < .01, R2 = 0.19), controlling for baseline body mass index. All were large effect sizes. In contrast, EAH was unrelated to emotional eating, disinhibition, and longer-term weight change. Amount of the test meal eaten in a hungry state was unrelated to these variables. While EAH has mainly been examined in children, these results expand its utility to adults. EAH seems to reflect naturalistic eating behavior, as shown by its relationship with short-term weight gain, drive to overconsume foods, and loss of control over eating. EAH may be a useful test to identify young adults at risk for weight gain and/or disordered eating, and may be a target for intervention.

Applying novel technologies and methods to inform the ontology of self-regulation.

Self-regulation is a broad construct representing the general ability to recruit cognitive, motivational and emotional resources to achieve long-term goals. This construct has been implicated in a host of health-risk behaviors, and is a promising target for fostering beneficial behavior change. Despite its clear importance, the behavioral, psychological and neural components of self-regulation remain poorly understood, which contributes to theoretical inconsistencies and hinders maximally effective intervention development. We outline a research program that seeks to define a neuropsychological ontology of self-regulation, articulating the cognitive components that compose self-regulation, their relationships, and their associated measurements. The ontology will be informed by two large-scale approaches to assessing individual differences: first purely behaviorally using data collected via Amazon's Mechanical Turk, then coupled with neuroimaging data collected from a separate population. To validate the ontology and demonstrate its utility, we will then use it to contextualize health risk behaviors in two exemplar behavioral groups: overweight/obese adults who binge eat and smokers. After identifying ontological targets that precipitate maladaptive behavior, we will craft interventions that engage these targets. If successful, this work will provide a structured, holistic account of self-regulation in the form of an explicit ontology, which will better clarify the pattern of deficits related to maladaptive health behavior, and provide direction for more effective behavior change interventions.

An investigation of two dimensions of impulsivity as predictors of loss-of-control eating severity and frequency.

Loss-of-control (LOC) eating episodes represent one form of dysregulated eating common to full- and sub-threshold eating disorders. Extensive evidence suggests that impulsivity, particularly in the context of negative affect and/or depression, may play an important etiological role in the development and maintenance of LOC eating. However, most prior studies have considered LOC eating as a dichotomous rather than dimensional construct, and few studies have considered the interaction of multiple dimensions of impulsivity while also accounting for the role of depressive symptoms. The present study examined the independent and interacting effects of two facets of impulsivity-response inhibition and negative urgency-on LOC eating episode severity and frequency among college women (N = 102). Depressive symptom severity was included as a covariate. Results indicated that greater negative urgency was associated with greater LOC severity; this effect was moderated by response inhibition, such that the effect of urgency was particularly pronounced for individuals with higher response inhibition capacity. Negative urgency was the only significant predictor of LOC frequency. Depression had no significant effect on either LOC severity or frequency (ps ≥ 0.16). Results support the importance of considering multiple facets of impulsivity in predicting LOC eating behavior, and further indicate that factors influencing subjective severity and frequency of LOC may be distinct.

Predicting Change in Physical Activity: a Longitudinal Investigation Among Weight-Concerned College Women.

BACKGROUND: Engaging in regular physical activity (PA) is critical for health, and adopting a consistent PA routine early in life is associated with greater PA over the lifespan. College women with weight concerns are at risk for weight gain, which may be prevented with regular PA. However, little is known about changes in PA engagement in this at-risk group. PURPOSE: Using an outcome expectancy framework, this study used a prospective longitudinal design to examine changes in PA during the first 2 years of college. We tested for concurrent and prospective within-person relations between body satisfaction/perceived eating behavior and PA to determine when weight-concerned college women may increase or decrease PA. METHODS: Women who reported weight concerns at the start of college (n = 294) completed five assessments over 2 years, including measured weight, body/eating experiences, and 4 days of pedometer steps (per assessment). Multilevel models addressed the resulting nested data structure (days within assessments within participants). RESULTS: Over 2 years, within-person change accounted for 65 % of PA variability (ICC = 0.35). PA was greatest at (and subsequent to) times when body satisfaction was lower, and when disinhibited eating and hedonic hunger were higher, than an individual's average (ps < 0.05). These changes were associated with 1-3 % of the recommended daily step totals. CONCLUSIONS: Weight-conscious college women show greater PA after negative eating and weight experiences. As these experiences change over time, health promotion efforts should help college women identify alternative, positive motivators for PA, which could facilitate consistent PA engagement.

The role of negative reinforcement eating expectancies in the relation between experiential avoidance and disinhibition.

OBJECTIVES: Eating-related disinhibition (i.e., a tendency to overeat in response to various stimuli) is associated with weight gain and poorer long-term weight loss success. Theoretically, experiential avoidance (i.e., the desire or attempts to avoid uncomfortable internal experiences), may predispose individuals to developing negative reinforcement eating expectancies (i.e., the belief that eating will help to mitigate distress), which in turn promote disinhibition. Such relationships are consistent with an acquired preparedness model, which posits that dispositions influence learning and subsequent behavior. Drawing from this framework, the current study represents the first investigation of relations between negative reinforcement eating expectancies, experiential avoidance (both general and food-specific) and disinhibited eating. In particular, the mediating role of negative reinforcement eating expectancies in the relation between experiential avoidance and disinhibited eating was examined. METHOD: Participants (N=107) were overweight and obese individuals presenting for behavioral weight loss treatment who completed measures of general and food-related experiential avoidance, negative reinforcement eating expectancies, and disinhibition. RESULTS: Experiential avoidance and negative reinforcement eating expectancies significantly related to disinhibition. Furthermore, the relation between experiential avoidance and disinhibition was mediated by negative reinforcement eating expectancies. DISCUSSION: The current study supports an acquired preparedness model for disinhibition, such that the relation between experiential avoidance and disinhibition is accounted for by expectations that eating will alleviate distress. Findings highlight the potential role of eating expectancies in models accounting for obesity risk, and identify negative reinforcement eating expectancies as a potential treatment target for reducing disinhibition.

Ecological momentary assessment of obesogenic eating behavior: combining person-specific and environmental predictors.

Obesity has been promoted by a food environment that encourages excessive caloric intake. An understanding of how the food environment contributes to obesogenic eating behavior in different types of individuals may facilitate healthy weight control efforts. In this study, Ecological Momentary Assessment (EMA) via palmtop computers was used to collect real-time information about participants' environment and eating patterns to predict overeating (i.e., greater than usual intake during routine meals/snacks, and eating outside of a participant's normal routine) that could lead to weight gain. Thirty-nine women (BMI = 21.6 ± 1.8; age = 20.1 ± 2.0 years; 61% white) of normal weight (BMI 18.5-25) completed the Three Factor Eating Questionnaire and the Power of Food Scale (PFS), and carried a palmtop computer for 7-10 days, which prompted them to answer questions about eating events, including a count of the types of good tasting high-calorie foods that were available. None of the self-report measures predicted overeating, but BMI interacted with the number of palatable foods available to predict overeating (P = 0.035). Compared to leaner individuals who reported a relatively low frequency of overeating regardless of the availability of palatable food, the probability of overeating among heavier individuals was very low in the absence of palatable food, but quickly increased in proportion to the number of palatable foods available. Our findings suggest that the eating behavior of those with higher relative weights is susceptible to the presence of palatable foods in the environment. Individuals practicing weight control may benefit from limiting their exposure to good tasting high-calorie food in their immediate environment.

Asymmetric prefrontal cortex activation in relation to markers of overeating in obese humans.

Dietary restraint is heavily influenced by affect, which has been independently related to asymmetrical activation in the prefrontal cortex (prefrontal asymmetry) in electroencephalograph (EEG) studies. In normal weight individuals, dietary restraint has been related to prefrontal asymmetry; however, this relationship was not mediated by affect. This study was designed to test the hypotheses that, in an overweight and obese sample, dietary restraint as well as binge eating, disinhibition, hunger, and appetitive responsivity would be related to prefrontal asymmetry independent of affect at the time of assessment. Resting EEG recordings and self-report measures of overeating and affect were collected in 28 overweight and obese adults. Linear regression analyses were used to predict prefrontal asymmetry from appetitive measures while controlling for affect. Cognitive restraint and binge eating were not associated with prefrontal asymmetry. However, disinhibition, hunger, and appetitive responsivity predicted left-, greater than right-, sided prefrontal cortex activation independent of affect. Findings in this study add to a growing literature implicating the prefrontal cortex in the cognitive control of dietary intake. Further research to specify the precise role of prefrontal asymmetry in the motivation toward, and cessation of, feeding in obese individuals is encouraged.

Are dietary restraint scales valid measures of moderate- to long-term dietary restriction? Objective biological and behavioral data suggest not.

Prospective studies indicate that elevated scores on dietary restraint scales predict bulimic symptom onset, but experiments indicate that assignment to dietary restriction interventions reduces bulimic symptoms. One possible explanation for the inconsistent findings is that the dietary restraint scales used in the former studies are not valid measures of dietary restriction. The authors previously found that dietary restraint scales were not inversely correlated with objective measures of short-term caloric intake (E. Stice, M. Fisher, & M. R. Lowe, 2004). In this follow-up report, 3 studies indicated that the Three-Factor Eating Questionnaire dietary restraint scale was not correlated with doubly labeled water estimated energy intake over 2-week periods or with observationally measured caloric intake over 3 months. Results from this study and others suggest that dietary restraint scales may not be valid measures of moderate- to long-term dietary restriction and imply the need to reinterpret findings from studies that have used dietary restraint scales.

A comparison of weight-control behaviors in African American and Caucasian women.

OBJECTIVES: The purpose of the present study was to examine whether there are overall differences in help-seeking, in specific weight control behaviors used, and in predictors of seeking professional help for weight loss between African American and Caucasian women. DESIGN: Cross-sectional study. SETTING: Participants were recruited from community sources in Philadelphia. PARTICIPANTS: One hundred twenty female participants were studied. Of these, 58% were African American. MAIN OUTCOME MEASURES: Participants completed a packet of measures assessing weight-control behaviors, body mass index, co-morbid medical conditions, socioeconomic status, disordered eating behavior, and body image. RESULTS: Caucasian women were significantly more likely to be classified as high help-seekers than were African American women, X2 = 4.27, P = .04. Caucasian women were more likely to use commercial weight loss programs, X2 = 4.25, P = .04, while African American women were more likely to try herbal supplements for weight control, X2 = 6.21, P = .01. Higher scores on a measure of body image, responsiveness to the food environment, and the disinhibition and hunger subscales of the Three-Factor Eating Questionnaire (TFEQ) predicted seeking professional help for Caucasian women only. CONCLUSIONS: The results indicate that African American and Caucasian women differ in overall weight-control efforts as well as in specific behaviors used. Furthermore, interactions were found between some factors associated with help-seeking and ethnicity. A better understanding of how available programs could be augmented to address the needs of African American and other minority groups is necessary.