Effects of laparoscopic sleeve gastrectomy on attentional processing of food-related information: evidence from eye-tracking

Conscious and pre-conscious attentional bias to food images in patients subjected to Roux-en-Y gastric bypass

Attentional bias (AB) to food after bariatric surgery might be a cognitive marker for weight regain. The visual probe task (VPT) is commonly used to capture AB at automatic, pre-conscious, and conscious orientation of attention. The aim of this study was to investigate how the preoperative BMI of patients submitted to Roux-en-Y gastric bypass (RYGB) impacts AB to food. We assessed patients who had preoperative BMI>50 (n = 28) or preoperative BMI<50 (n = 31) months after the RYGB procedure. Participants underwent clinical, psychological, and VPT evaluations. In VPT, pairs of food and matching non-food images were shown for 100 ms, 500 ms or 2000 ms and AB for food was assessed for each exposure time. A significant AB to food was observed at 2000 ms for all patients in this study, suggesting that the overall sample were consciously orienting their attention toward food cues after surgery, a finding that might be relevant for understanding weight control. When groups with preoperative BMI higher and lower than 50 kg/m2 were compared, a significant difference on AB to food stimuli at 500 ms was observed, controlling for excess weight lost since surgery and postoperative time. Subjects with preoperative BMI>50 had a positive and reliable AB to food while subjects with preoperative BMI<50 had a negative AB. This suggests that food stimuli have a higher incentive salience even after surgery for those with BMI>50, which might explain why subjects with higher preoperative weight have higher risks for weight regain. These results may indicate that RYGB can impact incentive salience for food cues in a differential manner, increasing conscious AB in all patients and decreasing pre-conscious AB only in those with BMI<50 kg/m2.

A systematic review and meta-analyses of food preference modifications after bariatric surgery

This systematic review and meta-analyses aimed to synthesize evidence of the link between bariatric surgery and changes in food preferences, considering the method of assessment. MEDLINE, Cochrane Library, Web of Science, Cinahl, PsychINFO, ProQuest, and Open grey were searched incorporating two blocks of terms ("Intervention" and "Food Preferences"). Interventional or observational studies involving patients (BMI ≥ 35 kg m^-2 ) with sleeve gastrectomy (SG) or Roux-en-Y Gastric Bypass (RYGB) and a control group were included. Meta-analyses were performed comparing the standardized daily mean percentage energy from proteins, carbohydrates, and lipids between preoperative and postoperative patients. Fifty-seven studies concerning 2,271 patients with RYGB and 903 patients with SG met the inclusion criteria, of which 24 were eligible for meta-analysis. Despite a total reduction in macronutrient intakes, the meta-analyses revealed a postoperative increase in percentage energy from proteins at 12 months (0.24, 95% CI: 0.03, 0.46, {I² } = 73%) and a decrease in percentage energy from fat at 1 month (-0.47, 95% CI: 0.86, 0.09, {I² } = 72%), up to 24 months (-0.20, 95% CI: -0.31, 0.08, {I² } = 0%). In conclusion, the present systematic review and meta-analyses showed changes of food preferences in terms of macronutrient, food selection and, overall food appreciation up to 5 years following bariatric surgery.

Ghrelin and Glucagon-Like Peptide-1: A Gut-Brain Axis Battle for Food Reward

Eating behaviors are influenced by the reinforcing properties of foods that can favor decisions driven by reward incentives over metabolic needs. These food reward-motivated behaviors are modulated by gut-derived peptides such as ghrelin and glucagon-like peptide-1 (GLP-1) that are well-established to promote or reduce energy intake, respectively. In this review we highlight the antagonizing actions of ghrelin and GLP-1 on various behavioral constructs related to food reward/reinforcement, including reactivity to food cues, conditioned meal anticipation, effort-based food-motivated behaviors, and flavor-nutrient preference and aversion learning. We integrate physiological and behavioral neuroscience studies conducted in both rodents and human to illustrate translational findings of interest for the treatment of obesity or metabolic impairments. Collectively, the literature discussed herein highlights a model where ghrelin and GLP-1 regulate food reward-motivated behaviors via both competing and independent neurobiological and behavioral mechanisms.

Changes in visual attention towards food cues after obesity surgery: An eye-tracking study

Research documented the effectiveness of obesity surgery (OS) for long-term weight loss and improvements in medical and psychosocial sequelae, and general cognitive functioning. However, there is only preliminary evidence for changes in attentional processing of food cues after OS. This study longitudinally investigated visual attention towards food cues from pre- to 1-year post-surgery. Using eye tracking (ET) and a Visual Search Task (VST), attentional processing of food versus non-food cues was assessed in n = 32 patients with OS and n = 31 matched controls without weight-loss treatment at baseline and 1-year follow-up. Associations with experimentally assessed impulsivity and eating disorder psychopathology and the predictive value of changes in visual attention towards food cues for weight loss and eating behaviors were determined. During ET, both groups showed significant gaze duration biases to non-food cues without differences and changes over time. No attentional biases over group and time were found by the VST. Correlations between attentional data and clinical variables were sparse and not robust over time. Changes in visual attention did not predict weight loss and eating disorder psychopathology after OS. The present study provides support for a top-down regulation of visual attention to non-food cues in individuals with severe obesity. No changes in attentional processing of food cues were detected 1-year post-surgery. Further studies are needed with comparable methodology and longer follow-ups to clarify the role of biased visual attention towards food cues for long-term weight outcomes and eating behaviors after OS.

Preliminary evidence that endoscopic gastroplication reduces food reward

Morbidly obese patients are most successfully treated with bariatric surgery. Although restrictive gastric surgery physically limits food intake, it is also suggested that eating behavior and food-reward mechanisms are affected. Therefore, eating behavior and food-reward were assessed in ten patients that underwent gastric volume reduction by endoscopic gastroplication. Patients participated in test days before and one, three and twelve months after the procedure. Weight loss, food intake, appetite, gastric emptying rate, food-reward (i.e. liking and wanting) and eating behavior were assessed. Body mass index decreased from 38.3 (37.6-42.6) to 33.9 (31.0-35.9) kg/m² after one year. Ad libitum food intake decreased significantly after one month, but not after one year. Gastric emptying rate did not change. AUC of VAS scores for desire to eat, quantity, fullness, hunger, snacking and satiety changed after one month, but not all remained significantly changed after one year. Thirst did not change. Liking scores of food items decreased significantly in the fasted as well as the satiated state after the procedure. Wanting scores did not change. Uncontrolled eating decreased significantly after three and twelve months; emotional eating was only significantly decreased after three months. The results show that food intake decreases, while VAS scores for appetite and eating behavior change accordingly. Liking, but not wanting of food items changed to benefit the weight losing patient. The effects were stronger at one-month follow-up than at 12 months, which may be a risk of relapse after initial successful weight loss. The effects of new bariatric procedures on food-reward should be studied in future randomized trials to further elucidate their impact. REGISTERED AT CLINICALTRIALS. GOV: NCT02381340.

Twenty Years of the Food Cravings Questionnaires: a Comprehensive Review

Purpose of Review

The Food Cravings Questionnaires (FCQs; Cepeda-Benito, Gleaves, Williams, & Erath, 2000) are among the most widely used instruments for measuring food cravings. In addition to the Food Cravings Questionnaire–Trait (FCQ–T) and the Food Cravings Questionnaire–State (FCQ–S), several modified versions have been developed as well. For their 20th anniversary, this article provides a comprehensive description of the FCQs and reviews studies on their psychometric properties and correlates.

Recent Findings

The FCQs and their modified versions have excellent internal reliability. Expectedly, the FCQ–T (and its derivatives) has higher retest-reliability than the FCQ–S as the FCQ–S is sensitive to situational changes such as food deprivation and food intake. However, while the FCQ–T is largely unaffected by such momentary states, it is also sensitive to change during weight-loss treatments and other interventions. Factor structure of the FCQ–T and FCQ–S has only partially been replicated. Construct validity of the FCQs is supported by experimental and longitudinal studies that measured food craving and food consumption in the laboratory and with ecological momentary assessment.

Summary

Numerous studies support reliability and validity of the FCQs and their modified versions, yet findings about their factor structures are inconsistent. Thus, using total scores or the short versions of the FCQs may be preferable.

Imaginal retraining decreases craving for high-calorie food in overweight and obese women: A randomized controlled trial

Overweight and obesity are epidemic conditions. Obesity is associated with somatic and psychological sequelae, including serious life-shortening disorders (e.g., diabetes). This study aimed to evaluate the efficacy of a newly developed imaginal variant of approach bias modification (i.e., imaginal retraining) for the reduction of craving for high-calorie food. In a randomized controlled trial, 384 women with a body mass index above 25 were allocated to a wait-list control group or to two variants of imaginal retraining (ratio: 1; 0.5; 0.5). The two intervention groups were sent a manual on imaginal retraining. One group was explicitly encouraged and instructed to use electronic reminders (RER); the standard retraining group (RS) was not encouraged to use electronic reminders. Assessments were 6 weeks apart and were carried out online. Craving for high-calorie food represented the primary outcome (based on the Visual Analog Scale, VAS). Secondary outcomes included the Food Cravings Questionnaire (FCQ-T-R). The study was registered as DRKS00017220. Women in the RER group utilized the retraining technique more often than those in the RS condition, and utilization frequency in turn was associated with improvement on craving and eating behavior scales. Both intention-to-treat and per-protocol analyses showed a favorable effect of the RER group, which achieved significance on the primary outcome, as well as on several other outcomes relative to controls at a small to medium effect size. For those participants who measured their weight before and after the assessment using a scale, weight loss in the RER group was significantly greater compared to the control group. Both retraining groups (RER: 39.4%; RS: 31.1%) reduced their subjective amount of eating relative to controls (24.2%). Approximately two-thirds of the sample (68.3%) performed the exercises at least once during the study period. The present results show that, when used regularly, imaginal retraining may reduce craving for high-calorie food in overweight and obese women. Of note, there was also evidence suggestive of weight reduction, although no diet or lifestyle change was recommended in the manual. Because a large subgroup neither read the manual nor performed the exercises, we recommend that future imaginal retraining be conveyed via short video clips.

Pre- and Postbariatric Subtypes and Their Predictive Value for Health-Related Outcomes Measured 3 Years After Surgery

BACKGROUND

Although bariatric surgery is the most effective treatment for severe obesity, a subgroup of patients shows insufficient postbariatric outcomes. Differences may at least in part result from heterogeneous patient profiles regarding reactive and regulative temperament, emotion dysregulation, and disinhibited eating. This study aims to subtype patients based on these aspects before and 2 years after bariatric surgery and tests the predictive value of identified subtypes for health-related outcomes 3 years after surgery.

METHODS

Within a prospective multicenter patient registry, N = 229 bariatric patients were examined before bariatric surgery, 2 and 3 years postoperatively via clinical interviews and self-report questionnaires. Pre- and postbariatric subtypes were differentiated by temperament, emotion dysregulation, and disinhibited eating using latent profile analyses (LPA). The predictive value of pre- and postbariatric subtypes for surgery outcomes measured 3 years postoperatively was tested via linear regression analyses.

RESULTS

LPA resulted in five prebariatric and three postbariatric subtypes which were significantly associated with different levels of general and eating disorder psychopathology. Post- versus prebariatric subtypes explained more variance regarding eating disorder psychopathology, depression, and quality of life assessed 3 years postoperatively, whereas neither pre- nor postbariatric subtypes predicted postbariatric weight loss. Patients with prebariatric deficits in self- and emotional control had an increased risk for showing these deficits postoperatively.

CONCLUSIONS

A re-evaluation of patients' psychological status after bariatric surgery is recommended to detect patients with potential risk for adverse psychological surgery outcomes in the long term.

Effect of Adolescent Bariatric Surgery on the Brain and Cognition: A Pilot Study

OBJECTIVE

Neurocognitive deficits in pediatric obesity relate to poor developmental outcomes. We sought preliminary evidence for changes in brain and cognitive functioning relevant to obesogenic behavior following vertical sleeve gastrectomy (VSG) in adolescents relative to wait-listed (WL) and healthy controls (HC).

METHODS

Thirty-six adolescents underwent fMRI twice 4 months apart, during executive, reward, and episodic memory encoding, in addition to behavioral testing for reward-related decision making.

RESULTS

VSG adolescents lost weight, while WL gained weight and HC did not change between time points. Gains in executive and reward-related performance were larger in VSG than control groups. Group × Time interaction (P < 0.05 corrected) in left prefrontal cortex during N-back showed greater presurgical activation and postsurgical reduction comparable to HC levels but increased in WL between time points. Similarly, left striatal parametric response to reward value reduced after surgery to HC levels; WL did not change. Memory-related medial temporal activation did not change in any group.

CONCLUSIONS

Results provide pilot evidence for functional brain changes induced by VSG in adolescents with severe obesity. Weight loss and gain were paralleled by reduced and increased prefrontal activation, respectively, suggesting neural plasticity related to metabolic change.

Explicit and Implicit Approach vs. Avoidance Tendencies towards High vs. Low Calorie Food Cues in Patients with Obesity and Active Binge Eating Disorder

Patients with binge eating disorder (BED) suffer from regular food binges with loss of control. This may be due to dysfunctional approach vs. avoidance tendencies towards food in BED. We applied an approach-avoidance task (AAT), in which n = 24 patients with obesity and active BED (OB-BED), n = 32 patients with obesity without current BED (OB), and n = 25 healthy controls (CO) either approached (“pulled”) or avoided (“pushed”) high (HC) vs. low calorie (LC) food pictures. We tested the hypothesis that OB-BED patients would show an approach bias (measured as different response times RT) towards HC food compared to the other groups. While there was no main effect for group or direction of movement, a significant main effect for calorie (p < 0.001; RT for HC significantly slower than for LC) was found. Repeated measures ANOVA (rm-ANOVA) for comparison of OB-BED vs. OB vs. CO revealed a significant three-fold interaction group × direction × calorie (p = 0.02). Against our hypothesis, the OB-BED group showed an avoidance bias for LC. In explicit ratings, OB-BED reported a significantly reduced urge to consume LC food compared to the OB group. Similar to OB-BED, CO also showed an avoidance bias for LC. The implications of our results are discussed and future directions in this field of research are presented.

Cognitive function and nonfood-related impulsivity in post-bariatric surgery patients

Initial evidence that cognitive function improves after bariatric surgery exists. The post-surgery increase in cognitive control might correspond with a decrease of impulsive symptoms after surgery. The present study investigated cognitive function and nonfood-related impulsivity in patients with substantial weight loss due to bariatric surgery by using a comparative cross-sectional design. Fifty post-bariatric surgery patients (postBS group) who had significant percent weight loss (M = 75.94, SD = 18.09) after Roux-en-Y gastric bypass (body mass index, BMI M_post = 30.54 kg/m², SD_post = 5.14) were compared with 50 age and gender matched bariatric surgery candidates (preBS group; BMI M_pre = 48.01 kg/m², SD_pre = 6.56). To measure cognitive function the following computer-assisted behavioral tasks were utilized: Iowa Gambling Task, Tower of Hanoi, Stroop Test, Trail Making Test-Part B, and Corsi Block Tapping Test. Impulsive symptoms and behaviors were assessed using impulsivity questionnaires and a structured interview for impulse control disorders (ICDs). No group differences were found with regard to performance-based cognitive control, self-reported impulsive symptoms, and ICDs. The results indicate that the general tendency to react impulsively does not differ between pre-surgery and post-surgery patients. The question of whether nonfood-related impulsivity in morbidly obese patients changes post-surgery should be addressed in longitudinal studies given that impulsive symptoms can be considered potential targets for pre- as well post-surgery interventions.

On the differentiation between trait and state food craving: Half-year retest-reliability of the Food Cravings Questionnaire-Trait-reduced (FCQ-T-r) and the Food Cravings Questionnaire-State (FCQ-S)

BACKGROUND

Food craving refers to an intense desire to consume a specific food. The Food Cravings Questionnaires (FCQs) assess food cravings on a trait and a state level.

METHOD

The current study examined half-year retest-reliability of the Food Cravings Questionnaire-Trait-reduced (FCQ-T-r) and the Food Cravings Questionnaire-State (FCQ-S) and reports associations with current food deprivation in female students.

RESULTS

The FCQ-T-r had higher retest-reliability (r tt = .74) than the FCQ-S (r tt = .39). Although trait food craving was correlated with state food craving, it was unaffected by current food deprivation.

CONCLUSIONS

Although state and trait food craving are interdependent, the FCQs are able to differentiate between the two. As scores of the FCQ-T-r represent a stable trait, but are also sensitive to changes in eating behavior, they may be useful for the investigation of the course of eating disorders and obesity.

A short version of the Food Cravings Questionnaire-Trait: the FCQ-T-reduced

One of the most often used instruments for the assessment of food cravings is the Food Cravings Questionnaire (FCQ), which consists of a trait (FCQ-T; 39 items) and state (FCQ-S; 15 items) version. Scores on the FCQ-T have been found to be positively associated with eating pathology, body mass index (BMI), low dieting success and increases in state food craving during cognitive tasks involving appealing food stimuli. The current studies evaluated reliability and validity of a reduced version of the FCQ-T consisting of 15 items only (FCQ-T-r). Study 1 was a questionnaire study conducted online among students (N = 323). In study 2, female students (N = 70) performed a working memory task involving food and neutral pictures. Study 1 indicated a one-factorial structure and high internal consistency (α = 0.94) of the FCQ-T-r. Scores of the FCQ-T-r were positively correlated with BMI and negatively correlated with dieting success. In study 2, participants reported higher state food craving after the task compared to before. This increase was positively correlated with the FCQ-T-r. Hours since the last meal positively predicted food craving before the task when controlling for FCQ-T-r scores and the interaction of both variables. Contrarily, FCQ-T-r scores positively predicted food craving after the task when controlling for food deprivation and the interaction term. Thus, trait food craving was specifically associated with state food craving triggered by palatable food-cues, but not with state food craving related to plain hunger. Results indicate high reliability of the FCQ-T-r. Replicating studies that used the long version, small-to-medium correlations with BMI and dieting success could be found. Finally, scores on the FCQ-T-r predicted cue-elicited food craving, providing further support of its validity. The FCQ-T-r constitutes a succinct, valid and reliable self-report measure to efficiently assess experiences of food craving as a trait.