Testing reward processing models of obesity using in-the-moment assessments of subjective enjoyment of food and non-food activities.

OBJECTIVE: Although altered reward processing is proposed to play a key role in obesity maintenance, the role of food enjoyment and enjoyment of non-food naturally rewarding activities ("non-food enjoyment") in obesity maintenance remains unknown. This study examined how food and non-food enjoyment were associated with baseline body mass index (BMI) and weight loss (WL) following year-long behavioral WL treatment. METHODS: At baseline, participants (MAge = 51.81; 73.8 % White, N = 279) with overweight/obesity completed a 7-day ecological momentary assessment (EMA) protocol inquiring about pleasure/enjoyment derived from eating and non-food activities over the past few hours. Participants also completed retrospective self-report measures of food/non-food enjoyment. With linear regressions, associations between EMA food/non-food enjoyment and BMI and post-treatment WL were examined. Race was included as a covariate. RESULTS: EMA and retrospective food/non-food enjoyment measures had modest concordance, providing preliminary psychometric support for the EMA measures. Partially consistent with hypotheses, greater EMA food enjoyment was associated with lower BMI (B = -1.03, p = .01) and with greater WL, though the latter association was not statistically significant (B = 1.15, p = .07). Exploratory analyses suggested that race was associated with food enjoyment (non-White participants had greater food enjoyment than White participants, d = 0.81, p = .005), and that race may have affected associations between food enjoyment and weight outcomes. Associations between non-food enjoyment and weight outcomes were small and nonsignificant (ps > .93). CONCLUSIONS: Results suggest enjoyment from food, but not from non-food domains, is associated with weight outcomes.

Feasibility, Acceptability, and Preliminary Target Engagement of a Healthy Physical Activity Promotion Intervention for Bulimia Nervosa: Development and Evaluation via Case Series Design.

Bulimia nervosa (BN) is characterized by a pattern of binge eating and compensatory behaviors as well as an overemphasis on body weight and shape in self-evaluation. Although cognitive behavioral therapy (CBT) is efficacious, recent reviews suggest that only 30% of patients reach abstinence at posttreatment. One potential reason for these poor outcomes is that CBT fails to adequately reduce elevated negative affect (NA) and shape and weight concern, which have been shown to be correlated with poorer treatment outcomes in BN. Therefore, novel treatment components that focus on improving NA and shape and weight concern are needed in order to enhance outcomes. Promoting physical activity (PA) is a promising avenue through which to reduce NA and improve body image in healthy individuals, other clinical populations (e.g., individuals with depression or anxiety), and individuals with eating disorders. While prescribing PA for individuals with BN has been controversial (due to concerns that exercise maybe be used to compensate for binge episodes or become driven or compulsive), this approach may have many benefits, including promoting healthy lifetime exercise habits that reduce likelihood of relapse through the improvement of emotion regulation skills and weight regulation. Given the promise of PA for targeting key maintenance factors of BN, we developed a 12-session healthy PA promotion intervention for BN and tested initial feasibility, acceptability, and preliminary target engagement in an iterative case series design (n = 3). The treatment provided cognitive-behavioral skills designed to identify, practice, and achieve behavioral goals while asking patients to engage in up to 150 minutes of moderate-to-vigorous PA per week, which was preplanned during each session with the client's therapist. Results suggested that the healthy PA promotion intervention was both feasible and acceptable to deliver. In addition, the intervention resulted in a clinically significant decrease in BN symptom frequency in each participant. Further, participants showed clinically significant decreases in NA and shape and weight concern. The current study demonstrates that healthy PA interventions can have beneficial effects on BN symptoms, NA, and shape and weight concern. However, due to the small sample size, conclusions must be treated with caution. Future research should investigate additional approaches for promoting healthy PA and include a larger sample in order to further test initial efficacy of this treatment approach.

Gender differences in the effect of gamification on weight loss during a daily, neurocognitive training program.

A major contributor to the obesity epidemic is the overconsumption of high-calorie foods, which is partly governed by inhibitory control, that is, the ability to override pre-prepotent impulses and drives. Computerized inhibitory control trainings (ICTs) have demonstrated qualified success at affecting real-world health behaviors, and at improving weight loss, particularly when repeated frequently over an extended duration. It has been proposed that gamification (i.e., incorporating game-like elements such as a storyline, sounds, graphics, and rewards) might enhance participant interest and thus training compliance. Previous findings from a mostly female sample did support this hypothesis; however, it might be expected that the effects of gamification differ by gender such that men, who appear more motivated by gaming elements, stand to benefit more from gamification. The present study evaluated whether gender moderated the effect of a gamified ICT on weight loss. Seventy-six overweight individuals received a no-sugar-added dietary prescription and were randomized to 42 daily and 2 weekly ICTs focused on sweet foods that were either gamified or nongamified. Results supported the hypothesis that gamification elements had a positive effect on weight loss for men and not women (p = .03). However, mechanistic hypotheses for the moderating effect (in terms of enjoyment, compliance, and improvements in inhibitory control) were generally not supported (p's > .20). These results suggest that gamification of ICTs may boost weight loss outcomes for men and not women, but further research is needed to determine the specific mechanisms driving this effect and to arrive at gamification elements that enhance effects for both men and women.

Characterizing rates of physical activity in individuals with binge eating disorder using wearable sensor technologies and clinical interviews.

OBJECTIVE: Research suggests physical activity (PA) improves behavioural, psychological and behavioural symptoms in individuals with binge eating disorder (BED), yet self-reported PA is notably low. Little remains known about objective rates of PA and subclinical levels of maladaptive PA (i.e., compensatory or driven PA), and few studies have attempted to understand the role that dissatisfaction and overvaluation with shape and weight plays in promoting PA in individuals with BED. We sought to characterize PA and investigate whether elevated rates of shape and weight concerns contribute to rates of PA in individuals with BED. METHOD: Individuals meeting DSM-5 diagnosis of BED (N = 56) completed the Eating Disorder Examination and wore a Fitbit Flex 2 for 1 week. RESULTS: On average, participants recorded 7621.12 (SD = 3034.20) daily steps and 194.30 (SD = 161.45) weekly moderate-to-vigorous PA minutes. About 21% of participants reported subclinical levels of maladaptive PA. Greater shape and weight overvaluation predicted lower duration of compensatory PA. CONCLUSION: A small percentage of individuals with BED are engaging in subclinical levels of maladaptive PA, and there is a need to identify factors that influence rates of PA in individuals with BED.

Hedonic hunger as a mechanism of action in outpatient cognitive behavioral therapy for bulimia nervosa.

OBJECTIVE: Hedonic hunger (i.e., the motivation to consume palatable foods in the absence of an energy deficit) has been associated with the onset and maintenance of loss of control (LOC) eating. However, it remains underexplored as a mechanism of action in outpatient cognitive behavioral therapy (CBT) for bulimia nervosa (BN). In the present study, we hypothesized that reductions in hedonic hunger would significantly mediate reductions in overall eating pathology and LOC episodes in two samples (N1 = 28, N2 = 23) of 20 and 16 sessions, respectively. METHOD: Participants completed the Eating Disorder Examination (EDE) and Power of Food Scale (PFS) at pre- and post-treatment. RESULTS: In both samples, EDE Global scores, LOC episodes, and PFS Total scores significantly improved over the course of treatment. In Sample 1, significant indirect effects of PFS Total scores on EDE Global scores and LOC episodes were observed. In Sample 2, the indirect effect of PFS Total scores was significant on EDE Global scores and nonsignificant on LOC episodes though it followed a similar pattern of change. DISCUSSION: Results suggest that reductions in hedonic hunger are associated with better outcomes in CBT for BN. Replication and further research is needed to elucidate the treatment components driving these reductions.

Computerized neurocognitive training for improving dietary health and facilitating weight loss.

Nearly 70% of Americans are overweight, in large part because of overconsumption of high-calorie foods such as sweets. Reducing sweets is difficult because powerful drives toward reward overwhelm inhibitory control (i.e., the ability to withhold a prepotent response) capacities. Computerized inhibitory control trainings (ICTs) have shown positive outcomes, but impact on real-world health behavior has been variable, potentially because of limitations inherent in existing paradigms, e.g., low in frequency, intrinsic enjoyment, personalization, and ability to adapt to increasing ability. The present study aimed to assess the feasibility, acceptability, and efficacy of a gamified and non-gamified, daily, personalized, and adaptive ICT designed to facilitate weight loss by targeting consumption of sweets. Participants (N = 106) were randomized to one of four conditions in a 2 (gamified vs. non-gamified) by 2 (ICT vs. sham) factorial design. Participants were prescribed a no-added-sugar diet and completed 42 daily, at-home trainings, followed by two weekly booster trainings. Results indicated that the ICTs were feasible and acceptable. Surprisingly, compliance to the 44 trainings was excellent (88.8%) and equivalent across both gamified and non-gamified conditions. As hypothesized, the impact of ICT on weight loss was moderated by implicit preference for sweet foods [F(1,95) = 6.17, p = .02] such that only those with higher-than-average implicit preference benefited (8-week weight losses for ICT were 3.1% vs. 2.2% for sham). A marginally significant effect was observed for gamification to reduce the impact of ICT. Implications of findings for continued development of ICTs to impact health behavior are discussed.

Slowing down and taking a second look: Inhibitory deficits associated with binge eating are not food-specific.

Poor inhibitory control may contribute to the maintenance of binge eating (BE) among overweight and obese individuals. However, it is unknown whether deficits are general or specific to food (versus other attractive non-food stimuli), or whether observed deficits are attributable to increased depressive symptoms in BE groups. In the current study, we hypothesized that individuals with BE would display inhibitory control deficits, with more pronounced deficits occurring when food stimuli were used. Overweight or obese participants with (n = 25) and without (n = 65) BE completed a Stop Signal Task (SST) with distinct task blocks featuring food-specific stimuli, positive non-food stimuli, or neutral stimuli. The BE group exhibited poorer inhibitory control across SST stimuli types (p = .003, ηp(2)=.10), but deficits did not differ by stimuli type (p = .68, ηp(2) < .01). Including depression as a covariate did not significantly alter results. Results suggest individuals with BE display inhibitory control deficits compared to controls; however, deficits do not appear to be specific to stimuli type. Furthermore, inhibitory control deficits do not appear to be associated with mood disturbance in the BE group. Replication and further research is needed to guide treatment targets.