Characterization of early non-responders within behavioral weight loss treatment.

Objective: Given that low early (4 weeks) weight loss (WL) predicts longer-term WL, the purpose of this study was to identify factors associated with poor early WL. Methods: 438 adults with overweight/obesity participating in an Internet-delivered behavioral WL program provided weights at baseline and 4 weeks. Participants were stratified by percent WL at 4 weeks: LOW: <2% WL, MEDIUM: 2 to <4% WL, HIGH: ≥4% WL and groups were compared on baseline variables (demographics, physical activity, and psychosocial measures) and 4-week intervention adherence. Results: 37.4%, 40.9%, and 21.7% of participants had LOW, MEDIUM, and HIGH early WL respectively. LOW was more likely to be female compared to HIGH and less likely to be non-Hispanic White compared to MEDIUM and HIGH (p's<0.05). After controlling for demographic differences, LOW had lower baseline physical activity compared to HIGH and watched fewer video lessons, self-monitored calorie intake and weight on fewer days, and were less likely to achieve the exercise goal compared to MEDIUM and HIGH (p's<0.05). Conclusion: Findings can inform future adaptive interventions which tailor treatment based upon early WL to improve WL outcomes for more individuals.

An Adaptive Telephone Coaching Intervention for Patients in an Online Weight Loss Program: A Randomized Clinical Trial.

Importance: Weight loss (WL) during the first month of a behavioral program is associated with longer-term WL. Testing of translatable and adaptive obesity programs is needed. Objective: To compare brief, extended, and no telephone coaching for individuals with suboptimal response (ie, 1-month WL <4%) within an online WL program. Design, Setting, and Participants: This randomized clinical trial with enrollment between March 2019 and April 2022 (data collection completed May 2023) was conducted at an academic research center in the US. Eligible participants included adults aged 18 to 70 years with daily access to internet and a body mass index between 25 and 45. Interventions: All participants received an automated online WL program (4 months) and WL maintenance program (8 months), consisting of video lessons, self-monitoring, and personalized feedback. Participants were randomized, such that individuals with suboptimal response received either brief telephone coaching (3 calls during weeks 5-8), extended telephone coaching (12 calls during weeks 5-16), or no coaching (control). Coaching included education, problem solving, and goal setting, and promoted engagement with the online program. Main Outcomes and Measures: The primary outcomes were percent weight change and proportion of participants achieving 5% or greater WL at 4 and 12 months. A priori hypotheses for WL were that WL for extended coaching would be greater than for brief coaching, and both extended and brief coaching would be greater than no coaching (control). A longitudinal mixed-effects model with participant-specific intercept was used to examine intervention effects on percent WL at 4 and 12 months. Secondary analyses focused on program engagement and cost/kilogram of WL. Results: The study included a total of 437 participants who reported WL at 1 month (mean [SD] age, 50.8 [11.4] years; mean [SD] BMI, 34.6 [5.0]; 305 female [69.8%] and 132 male [30.2%]) with 148 randomized to extended coaching, 143 assigned to brief coaching, and 146 assigned to the control group. Of all participants, 346 (79.2%) were considered to have a suboptimal response. WL at 4 months was significantly greater in the extended coaching group (mean [SD] WL, -7.0% [5.1%]) and brief coaching group (mean [SD] WL, -6.2% [4.7%]) vs the control group (mean [SD] WL, -4.5% [4.7%]) (P < .001). Similarly, the proportion of participants achieving 5% or greater WL at 4 months was greater in the extended coaching group (89 participants [65.9%]) and brief coaching group (77 participants [58.5%]) vs control group (46 participants [36.5%]) (P < .001). At 12 months, a similar pattern was observed for achievement of 5% WL or greater (extended coaching, 63 participants [48.1%]; brief coaching, 58 participants [45.9%]; control, 38 participants [32.8%]; P = .03). Percent WL at 12 months was significantly higher in extended coaching vs control (mean [SD] WL for extended coaching, -5.5% [6.7%]; mean [SD] WL for control, -3.9% [7.4%]; P = .03) but not for brief coaching (mean [SD] WL, -4.9% [6.1%]).Both the brief and extended coaching groups watched more lessons and self-monitored on more days compared with the control group. The cost per additional kilogram of WL, beyond that of the control group, was $50.09 for brief coaching and $92.65 for extended coaching. Conclusions and Relevance: In this randomized clinical trial testing an adaptive intervention, the provision of coaching for individuals with suboptimal response improved WL and was cost-effective; further testing in clinical settings (eg, health care systems) is warranted. Trial Registration: ClinicalTrials.gov Identifier: NCT03867981.

Internalized weight bias is associated with perceived exertion and affect during exercise in a sample with higher body weight.

OBJECTIVE: For individuals with overweight/obesity, internalized weight bias (IWB) is linked to low physical activity (PA). This study used a laboratory-based paradigm to test the hypothesis that IWB moderates the association between heart rate (HR) and perceived exertion and affect during PA. METHODS: Participants with overweight/obesity completed 30-min of supervised moderate-intensity treadmill walking (65%-75% of age-predicted maximal HR). Body Mass Index (BMI) and Weight Bias Internalization Scale were assessed at baseline. HR was monitored every minute; perceived exertion and affect were assessed every 5 min. Linear mixed models were employed with random effects of time and participant. RESULTS: The sample (n = 59; 79.7% female, 91.5% white) had an average BMI = 32.1 kg/m2 (SD: 3.3), and age = 47.1 (SD: 10.3) years. There was a main effect of IWB on perceived exertion (greater IWB was associated with greater perceived exertion during exercise; p < 0.001). There was an interaction of IWB and HR on affect (B = -0.01, p < 0.01). For individuals with high IWB, HR elevations were associated with a negative affective response during exercise. For individuals with low IWB, HR elevations were associated with increased positive affect during PA. CONCLUSIONS: Findings indicate that among individuals of higher body weight, IWB is associated with reporting higher perceived exertion during 30 min of moderate intensity PA. IWB moderated the relationship between increasing HR during exercise and affect. Among individuals with overweight/obesity who report IWB, the initial experience of PA may be harder and more unpleasant, with lasting implications for the adoption of PA.

Food reward sensitivity, impulsivity, and weight change during and after a 3-month weight loss program.

BACKGROUND: Greater sensitivity to food rewards and higher levels of impulsivity (and an interaction between these variables, termed "reinforcement pathology") have been associated with obesity in cross-sectional studies. Less is known regarding how these constructs may impact attempts at weight loss or longer-term weight loss maintenance. METHODS: We provided 75 adults (69%Female, 84%White, age = 50.8y, BMI = 31.2kg/m2) with a 3-month Internet-based weight loss program and assessed weight, food reward sensitivity (via the Power of Food Scale [PFS]), and impulsivity (via Go No-Go [GNG] and Delay Discounting [DD] computer tasks) at baseline and at Months 3, 6, 9, and 12. No additional intervention was provided Months 3-12. Multi-level mixed-effect models were used to examine changes in PFS, GNG, and DD over time and associations between these measures and weight loss/regain. RESULTS: Participants lost 6.0±1.1kg Months 0-3 and regained 2.4±1.1kg Months 3-12. Across time points, higher PFS scores were associated with higher weight, p = .007; however, there were no significant associations between GNG or DD and weight nor between the interactions of PFS and GNG or DD and weight, ps>.05. There were significant decreases from Months 0-3 in PFS, GNG, and DD, ps < .05; however, neither baseline values nor changes were significantly associated with weight change and there were no significant associations between the interactions of PFS and GNG or DD and weight change, ps>.05. CONCLUSION: Results demonstrated an association between food reward sensitivity and weight. Further, decreases in both food reward sensitivity and impulsivity were observed during an initial weight loss program, but neither baseline levels nor improvements were associated with weight change. Taken together, results suggest that the constructs of food reward sensitivity, impulsivity, and reinforcement pathology may have limited clinical utility within behavioral weight management interventions. Future intervention studies should examine whether food-related impulsivity tasks lead to a similar pattern of results.

DIAL now protocol: A randomized trial examining the provision of phone coaching to those with sub-optimal early weight loss during an Internet weight management program.

BACKGROUND: While low-intensity Internet-delivered weight loss (IDWL) programs are efficacious, many patients fail to achieve clinically significant weight loss (WL). Given the positive association between 4-week and post-treatment WL, providing a more intensive intervention for those with sub-optimal 4-week WL may improve outcomes for a greater proportion of individuals. This stepped-care approach would minimize cost by reserving more aggressive treatment for those with sub-optimal early WL. OBJECTIVE: This randomized trial examines whether the provision of brief or extended phone coaching for those with sub-optimal early WL improves 4- and 12-month WL when compared to no coaching. Secondary aims include examination of cost/kg WL and intervention engagement. METHODS: 450 individuals (age 18-70 years, BMI: 25-45 kg/m2) will be randomized to: 1) IDWL+3 weeks of coaching ('Brief'), 2) IDWL+12 weeks of coaching ('Extended'), or 3) IDWL only ('Control'). All individuals will receive a 4-month IDWL program followed by an 8-month IDWL maintenance program. At week 4, individuals will be classified as early sub-optimal responders (<4% WL) or initial responders (≥4% WL). Individuals with sub-optimal early WL randomized to 'Brief' or 'Extended' will receive 3 and 12 weeks of phone coaching respectively, starting at week 5. Those with sub-optimal early WL randomized to 'Control', and initial responders will not receive any coaching. Assessments will occur at 4 and 12 months. DISCUSSION: Study findings can inform the development of more effective IDWL programs. This model which provides additional support to those with sub-optimal early WL can easily be translated into healthcare and community settings.

The Effects of Experimental Manipulation of Sleep Duration on Neural Response to Food Cues.

Despite growing literature on neural food cue responsivity in obesity, little is known about how the brain processes food cues following partial sleep deprivation and whether short sleep leads to changes similar to those observed in obesity. We used functional magnetic resonance imaging (fMRI) to test the hypothesis that short sleep leads to increased reward-related and decreased inhibitory control-related processing of food cues.In a within-subject design, 30 participants (22 female, mean age = 36.7 standard deviation = 10.8 years, body mass index range 20.4-40.7) completed four nights of 6 hours/night time-in-bed (TIB; short sleep) and four nights of 9 hours/night TIB (long sleep) in random counterbalanced order in their home environments. Following each sleep condition, participants completed an fMRI scan while viewing food and nonfood images.A priori region of interest analyses revealed increased activity to food in short versus long sleep in regions of reward processing (eg, nucleus accumbens/putamen) and sensory/motor signaling (ie, right paracentral lobule, an effect that was most pronounced in obese individuals). Contrary to the hypothesis, whole brain analyses indicated greater food cue responsivity during short sleep in an inhibitory control region (right inferior frontal gyrus) and ventral medial prefrontal cortex, which has been implicated in reward coding and decision-making (false discovery rate corrected q = 0.05).These findings suggest that sleep restriction leads to both greater reward and control processing in response to food cues. Future research is needed to understand the dynamic functional connectivity between these regions during short sleep and whether the interplay between these neural processes determines if one succumbs to food temptation.

Initial Weight Loss Response as an Indicator for Providing Early Rescue Efforts to Improve Long-term Treatment Outcomes.

PURPOSE OF REVIEW: There is a large variability in response to behavioral weight loss (WL) programs. Reducing rates of obesity and diabetes may require more individuals to achieve clinically significant WL post-treatment. Given that WL within the first 1-2 months of a WL program is associated with long-term WL, it may be possible to improve treatment outcomes by identifying and providing additional intervention to those with poor initial success (i.e., "early non-responders"). We review the current literature regarding early non-response to WL programs and discuss how adaptive interventions can be leveraged as a strategy to "rescue" early non-responders. RECENT FINDINGS: Preliminary findings suggest that adaptive interventions, specifically stepped care approaches, offer promise for improving outcomes among early non-responders. Future studies need to determine the optimal time point and threshold for intervening and the type of early intervention to employ. Clinicians and researchers should consider the discussed factors when making treatment decisions.

Identifying the mechanisms through which behavioral weight-loss treatment improves food decision-making in obesity.

OBJECTIVES: Behavioral weight loss (BWL) programs are the recommended treatment for obesity, yet it is unknown whether these programs change one's ability to use self-control in food choices and what specific mechanisms support such change. Using experimental economics methods, we investigated whether changes in dietary behavior in individuals with obesity following BWL are driven by one or more of the following potential mechanisms: changes in the perception of the 1) health or 2) taste of food items, and/or 3) shifting decision weights for health versus taste attributes. Therefore, we compared these mechanisms between obese participants and lifetime normal weight controls (NW) both before and after BWL. METHODS: Females with obesity (N = 37, mean BMI = 33.2) completed a food choice task involving health ratings, taste ratings, and decision-making pre- and post-standard BWL intervention. NW controls (N = 30, BMI = 22.4) completed the same task. RESULTS: Individuals with obesity exhibited increased self-control (selecting healthier, less tasty food choices) post-treatment. However, their rates of self-control remained significantly lower than NW. We found no differences in initial health perceptions across groups, and no changes with treatment. In contrast, taste ratings and the relative value of taste versus health decreased following treatment. Although, post-treatment participants continued to perceive unhealthy foods as tastier and used less self-control than NW controls, they showed significant improvements in these domains following a BWL intervention. CONCLUSIONS: To help individuals improve dietary decisions, additional research is needed to determine how to make greater changes in taste preferences and/or the assignment of value to taste versus health attributes in food choices.

Relative differences in resting-state brain connectivity associated with long term intensive lifestyle intervention.

A number of studies have reported that type 2 diabetes mellitus (T2DM) is associated with alterations in resting-state activity and connectivity in the brain. There is also evidence that interventions involving physical activity and weight loss may affect brain functional connectivity. In this study, we examined the effects of nearly 10 years of an intensive lifestyle intervention (ILI), designed to induce and sustain weight loss through lower caloric intake and increased physical activity, on resting-state networks in adults with T2DM. We performed a cross-sectional comparison of global and local characteristics from functional brain networks between individuals who had been randomly assigned to ILI or a control condition of health education and support. Upon examining brain networks from 312 participants (average age: 68.8 for ILI and 67.9 for controls), we found that ILI participants (N=160) had attenuated local efficiency at the network-level compared with controls (N=152). Although there was no group difference in the network-level global efficiency, we found that, among ILI participants, nodal global efficiency was elevated in left fusiform gyrus, right middle frontal gyrus, and pars opercularis of right inferior frontal gyrus. These effects were age-dependent, with more pronounced effects for older participants. Overall these results indicate that the individuals assigned to the ILI had brain networks with less regional and more global connectivity, particularly involving frontal lobes. Such patterns would support greater distributed information processing. Future studies are needed to determine if these differences are associated with age-related compensatory function in the ILI group or worse pathology in the control group.

Acute Changes in Sleep Duration on Eating Behaviors and Appetite-Regulating Hormones in Overweight/Obese Adults.

There is considerable interest in the role of sleep in weight regulation, yet few studies have examined this relationship in overweight/obese (OW/OB) adults. Using a within-subject, counterbalanced design, 12 OW/OB women were studied in lab with two nights of short (5 hr time in bed [TIB]) and two nights of long (9 hr TIB) sleep. Hunger, consumption at a buffet, and fasting hormone levels were obtained. Significant polysomnographic differences occurred between conditions in total sleep time and sleep architecture (ps < .001). Percent energy from protein at the buffet increased following short sleep. No differences were observed for total energy intake or measured hormones. Further research is needed to determine how lengthening sleep impacts weight regulation in OW/OB adults.

Failure to replicate depletion of self-control.

The limited resource or strength model of self-control posits that the use of self-regulatory resources leads to depletion and poorer performance on subsequent self-control tasks. We conducted four studies (two with community samples, two with young adult samples) utilizing a frequently used depletion procedure (crossing out letters protocol) and the two most frequently used dependent measures of self-control (handgrip perseverance and modified Stroop). In each study, participants completed a baseline self-control measure, a depletion or control task (randomized), and then the same measure of self-control a second time. There was no evidence for significant depletion effects in any of these four studies. The null results obtained in four attempts to replicate using strong methodological approaches may indicate that depletion has more limited effects than implied by prior publications. We encourage further efforts to replicate depletion (particularly among community samples) with full disclosure of positive and negative results.

Greater Food-Related Stroop Interference Following Behavioral Weight Loss Intervention.

OBJECTIVE: Individuals who have successfully lost and maintained weight have slower reaction times on food-related Stroop tasks, indicating greater cognitive interference to food stimuli compared to obese and normal weight individuals. It remains unclear whether this interference is a preexisting characteristic of weight loss maintainers or if food-interference changes in obese individuals as they lose weight. METHOD: To examine potential changes in food-related interference, a food-Stroop paradigm was used to measure responses to food versus non-food words in 13 obese women before and after a 12-week behavioral weight loss program. RESULTS: Participants achieved a mean weight loss of 5.12 kg through the behavioral weight loss program. Their reaction time to food words became significantly slower (p<0.001) and they made significantly more errors (p<0.01) following treatment. DISCUSSION: These findings suggest that through behavioral weight loss treatment obese individuals experience increased interference toward food words, which may reflect increased salience of food-related cues. Future research is needed to determine whether increases in interference are related to better weight loss and maintenance.

Cortical thickness of the cognitive control network in obesity and successful weight loss maintenance: a preliminary MRI study.

Cortical thickness of the cognitive control network was contrasted between obese (OB), successful weight loss maintainers (SWLM), and lean individuals. OB individuals had significant thinning, most notably in the anterior cingulate and posterior parietal cortices. SWLM individuals exhibited trends towards thicker cortex than OB individuals, which may be important in future studies.

Brain response to food stimulation in obese, normal weight, and successful weight loss maintainers.

As many people struggle with maintenance of weight loss, the study of successful weight loss maintainers (SWLM) can yield important insights into factors contributing to weight loss maintenance. However, little research has examined how SWLM differ from people who are obese or normal weight (NW) in brain response to orosensory stimulation. The goal of this study was to determine if SWLM exhibit different brain responses to orosensory stimulation. Brain response to 1-min orosensory stimulation with a lemon lollipop was assessed using functional magnetic resonance imaging among 49 participants, including SWLM (n = 17), NW (n = 18), and obese (n = 14) controls. Significant brain responses were observed in nine brain regions, including the bilateral insula, left inferior frontal gyrus, left putamen, and other sensory regions. All regions also exhibited significant attenuation of this response over 1 min. The SWLM exhibited greater response compared with the other groups in all brain regions. Findings suggest that the response to orosensory stimulation peaks within 40 s and attenuates significantly between 40 and 60 s in regions associated with sensation, reward, and inhibitory control. Greater reactivity among the SWLM suggests that greater sensory reactivity to orosensory stimulation, increased anticipated reward, and subsequently greater inhibitory processing are associated with weight loss maintenance.

Individual differences in nucleus accumbens activity to food and sexual images predict weight gain and sexual behavior.

Failures of self-regulation are common, leading to many of the most vexing problems facing contemporary society, from overeating and obesity to impulsive sexual behavior and STDs. One reason that people may be prone to engaging in unwanted behaviors is heightened sensitivity to cues related to those behaviors; people may overeat because of hyperresponsiveness to food cues, addicts may relapse following exposure to their drug of choice, and some people might engage in impulsive sexual activity because they are easily aroused by erotic stimuli. An open question is the extent to which individual differences in neural cue reactivity relate to actual behavioral outcomes. Here we show that individual differences in human reward-related brain activity in the nucleus accumbens to food and sexual images predict subsequent weight gain and sexual activity 6 months later. These findings suggest that heightened reward responsivity in the brain to food and sexual cues is associated with indulgence in overeating and sexual activity, respectively, and provide evidence for a common neural mechanism associated with appetitive behaviors.

Dietary restraint violations influence reward responses in nucleus accumbens and amygdala.

Numerous studies have demonstrated that consuming high-calorie food leads to subsequent overeating by chronic dieters. The present study investigates the neural correlates of such self-regulatory failures using fMRI. Chronic dieters (n = 50) and non-dieters (n = 50) consumed either a 15-oz glass of cold water or a 15-oz milkshake and were subsequently imaged while viewing pictures of animals, environmental scenes, people, and appetizing food items. Results revealed a functional dissociation in nucleus accumbens and amygdala activity that paralleled well-established behavioral patterns of eating observed in dieters and non-dieters. Whereas non-dieters showed the greatest nucleus accumbens activity in response to food items after water consumption, dieters showed the greatest activity after consuming the milkshake. Activity in the left amygdala demonstrated the reverse interaction. Considered together with previously reported behavioral findings, the present results offer a suggested neural substrate for diet failure.

Medial temporal lobe BOLD activity at rest predicts individual differences in memory ability in healthy young adults.

Human beings differ in their ability to form and retrieve lasting long-term memories. To explore the source of these individual differences, we used functional magnetic resonance imaging to measure blood-oxygen-level-dependent (BOLD) activity in healthy young adults (n = 50) during periods of resting fixation that were interleaved with periods of simple cognitive tasks. We report that medial temporal lobe BOLD activity during periods of rest predicts individual differences in memory ability. Specifically, individuals who exhibited greater magnitudes of task-induced deactivations in medial temporal lobe BOLD signal (as compared to periods of rest) demonstrated superior memory during offline testing. This relationship was independent of differences in general cognitive function and persisted across different control tasks (i.e., number judgment versus checkerboard detection) and experimental designs (i.e., blocked versus event-related). These results offer a neurophysiological basis for the variability in mnemonic ability that is present amongst healthy young adults and may help to guide strategies aimed at early detection and intervention of neurological and mnemonic impairment.

Medial prefrontal activity differentiates self from close others.

A key question in psychology and neuroscience is the extent to which the neural representation of others is incorporated with, or is distinct from, our concept of self. Recent neuroimaging research has emphasized the importance of a region in the medial prefrontal cortex [MPFC; Brodmann's area (BA) 10] when performing self-referent tasks. Specifically, previous studies have reported selective MPFC recruitment when making judgments about the self relative to a familiar but personally unknown other. The present event-related functional magnetic resonance imaging study extends these findings to judgments about personally known others. Subjects were imaged while making trait adjective judgments in one of the three conditions: (i) whether the adjective described the self; (ii) whether the adjective described an intimate other (i.e., a best friend); or (iii) whether the adjective was presented in uppercase letters. Making judgments about the self relative to an intimate other selectively activated the MPFC region previously implicated in the self-processing literature. These results suggest that while we may incorporate intimate others into our self-concept, the neural correlates of the self remain distinct from intimate and non-intimate others.

Reductions in neural activity underlie behavioral components of repetition priming.

Repetition priming is a nonconscious form of memory that is accompanied by reductions in neural activity when an experience is repeated. To date, however, there is no direct evidence that these neural reductions underlie the behavioral advantage afforded to repeated material. Here we demonstrate a causal linkage between neural and behavioral priming in humans. fMRI (functional magnetic resonance imaging) was used in combination with transcranial magnetic stimulation (TMS) to target and disrupt activity in the left frontal cortex during repeated classification of objects. Left-frontal TMS disrupted both the neural and behavioral markers of priming. Neural priming in early sensory regions was unaffected by left-frontal TMS--a finding that provides evidence for separable conceptual and perceptual components of priming.