Neural Response to Pictures of Food after Exercise in Normal-Weight and Obese Women

Post-exercise energy replacement might lead to reduced subsequent energy intake in women with constitutional thinness: Exploratory results from the NUTRILEAN project

While people with Constitutional Thinness (CT) declare a deep willingness to gain weight, there appetitive responses to energy balance manipulations remain unclear. The present work compares the effect of an acute exercise combined or not with an energy replacement load, on subsequent energy intake, appetite and food reward, between normal weight and women with CT. Anthropometric measurements, body composition (Dual X-ray absorptiometry-DXA) and aerobic capacity (VO2max) were assessed in 10 normal-weight (Body Mass Index-BMI): 20-25 kg/m2) and 10 C T (BMI<17.5 kg/m2) women (18-30 years). They randomly performed i) a resting session (CON); ii) an exercise session (EX); iii) an exercise session with energy replacement (EX + R). Their subsequent ad libitum intake, appetite feelings and food reward were evaluated (Leeds-Food-Preference-Questionnaire). CT showed a lower weight (p < 0,001), BMI(p < 0,001), Fat-Mass (%) (p = 0,003) and Fat-Free Mass (kg) (p < 0,001). CT showed a lower ad libitum energy intake on EX + R compared with CON (p = 0,008) and a higher Relative Energy Intake (REI) on CON compared with EX (p = 0,007) and EX + R (p < 0,001). A lower was observed during EX and EX + R compared with CON (p = 0,006,p = 0,009 respectively) in CT. No condition nor group effect was found for hunger. NW only showed a higher pre-meal fullness on EX + R compared to CON and EX (p < 0,001). Choice (p = 0,030), Explicit Liking (p = 0,016), Explicit Wanting (p = 0,004) and Implicit Wanting (p = 0,035) for taste were higher on EX + R than CON and EX. The decreased EI observed in CT when the exercise-induced energy expenditure is compensated by the ingestion of an equivalent energy load, might contribute to explain the difficulty to increase their energy balance and then induce weight gain. Further studies are needed to better understand their energy balance regulation to propose adapted weight gain strategies.

Acute high-intensity interval exercise improves food-related cognition in young adults with obesity: An ERP study

Purpose Cognitive function, particularly food-related cognition, is critical for maintaining a healthy weight and preventing the acceleration of obesity. High-Intensity Interval Exercise (HIIE) is an increasingly popular form of exercise and has been shown to improve physical fitness and cognitive function. However, there is limited research on the effects and underlying mechanisms of HIIE on general and food-related cognition among adults with obesity. The aim of the current study was to examine the influence of a single bout of HIIE on food-related cognition among young adults with obesity. Methods Fifteen young men with obesity (BMI = 33.88 ± 4.22, age = 24.60 ± 5.29 years) were recruited. Participants took part in a HIIE condition consisting of 30 minutes of stationary cycle exercise (5-min warm-up, 20-min HIIE and 5-min cool down), and a control session consisting of a time and attention-matched period of sedentary rest in a counterbalanced order. Behavioral (reaction time and accuracy) and event-related potential measures (P3 and the late positive potential, LPP) elicited during a food-related Flanker task were measured after the HIIE and control session. Results Shorter response times were observed following HIIE, regardless of congruency or picture type, with no change in accuracy. Increased P3 and LPP amplitudes were observed following HIIE relative to the control session. Conclusion The findings suggest a single bout of HIIE has a beneficial effect on general and food-related cognition among young adults with obesity, with increased recruitment of cognitive resources to support cognitive control. Future research is warranted to examine the dose-response relationship between acute bouts or longer participation in HIIE on food-related cognition in obesity.

Age-related differences in food-specific inhibitory control: Electrophysiological and behavioral evidence in healthy aging

The number of older adults in the United States is estimated to nearly double from 52 million to 95 million by 2060. Approximately 80-85% of older adults are diagnosed with a chronic health condition. Many of these chronic health conditions are influenced by diet and physical activity, suggesting improved diet and eating behaviors could improve health-related outcomes. One factor that might improve dietary habits in older adults is food-related inhibitory control. We tested whether food-related inhibitory control, as measured via behavioral data (response time, accuracy) and scalp-recorded event-related potentials (ERP; N2 and P3 components), differed between younger and older adults over age 55. Fifty-nine older adults (31 females [52.5%], M_age = 64, SD_age = 7.5) and 114 younger adults (82 females [71.9%], M_age = 20.8) completed two go/no-go tasks, one inhibiting to high-calorie stimuli and one inhibiting to low-calorie stimuli, while electroencephalogram (EEG) data were recorded. Older adults had slower overall response times than younger adults, but this was not specific to either food task. There was not a significant difference in accuracy between younger and older adults, but both groups' accuracy and response times were significantly better during the high-calorie task than the low-calorie task. For both the N2 and P3 ERP components, younger adults had larger no-go ERP amplitudes than older adults, but this effect was not food-specific, reflecting overall generalized lower inhibitory control processing in older adults. P3 amplitude for the younger adults demonstrated a specific food-related effect (greater P3 amplitude for high-calorie no-go than low-calorie no-go) that was not present for older adults. Findings support previous research demonstrating age-related differences in inhibitory control though those differences may not be specific to inhibiting towards food.

The effects of daily step goals of 10,000, 12,500, and 15,000 steps per day on neural activity to food cues: A 24-week dose-response randomized trial

INTRODUCTION

The purpose of this study was to examine the effect of different levels of sustained physical activity on neural reflections of attention allocated toward food cues in first year college women.

METHODS

Seventy-nine first-year college women (18.6 ± 0.5 years) were recruited to participate in the study. Women were randomly assigned to a daily step goal of 10,000, 12,500, or 15,000 for 24 weeks. Once during weeks 16-24, participants were shown pictures of plated meals or flowers with the neural response measured using the P300 and late positive potential (LPP) components of the scalp-recorded event-related potential. Diet was assessed using the automated 24-h recall.

RESULTS

Both the P300 and LPP amplitudes were significantly more positive to food versus flower pictures (ps < .001). There was no interaction between step group and picture condition for the P300 and LPP. However, the 12,500-step group showed a significantly elevated LPP amplitude in comparison to the other groups for both food and flowers (F(2,74) = 8.84; p < .001). The effect size for the combined results (food and flowers) was 0.56 between 10,000 and 12,500-step groups, and 0.75 between the 12,500- and 15,000-step groups. In addition, the 12,500 group reduced caloric consumption over the course of the intervention (t(1,74) = 3.35, p = .001, d_z  = 0.59).

CONCLUSION

Habitual physical activity of 10,000, 12,500, or 15,000 steps per day does not preferentially alter neural reflections toward food cues compared to flowers. There may be a nonlinear response to pleasant visual cues, with 12,500 steps per day eliciting higher LPPs than either 10,000 or 15,000.

Using event-related potentials to study food-related cognition: An overview of methods and perspectives for future research

Electroencephalography (EEG), and the measure of event-related potentials (ERPs) in particular, are useful methods to study the cognitive and cerebral mechanisms underlying the perception and processing of food cues. Further research on these aspects is necessary to better understand how cognitive functioning may influence food choices in different populations (e.g. obese individuals, individuals with eating disorders). To help researchers in designing future studies, this article provides an overview of the methods used in the current literature on ERPs and food-related cognition. Several methodological aspects are explored to outline interesting perspectives for future research, including discussions on the main experimental tasks used, the cognitive functions assessed (e.g. inhibitory control, attentional processing), the characteristics of the participants recruited (e.g. weight status, eating behaviors), and the stimuli selected (e.g. food pictures, odors). The issues generated by some of these methodological choices are discussed, and a few guidelines are provided.

Testing the relationship between inhibitory control and soda consumption: An event-related potential (ERP) study

The intake of sugar-sweetened beverages (SSB) may detrimentally influence health outcomes. Drinking less soda may help manage SSB consumption, as soft drinks are a top contributor to SSB intake. One cognitive factor that may influence soda consumption is inhibitory control, or the ability to withhold a dominant response in order to correctly respond to one's environment. Increased inhibitory control plays a role in decreasing consumption of high-calorie foods, and strengthening inhibitory control may help individuals manage their food intake. However, neural response to soda beverages versus traditional non-sweetened beverages, such as water, and how it relates to soda consumption is unknown. In a sample of 116 healthy individuals (M = 20.56; SD = 2.08; 47.4% female), we measured soda consumption and tested event-related potential (ERP) measures of inhibitory control, including the N2 and P3 components, during soda-specific and neutral comparison go/no-go tasks. Female participants consumed less soda on average than males, and as participants got older, they consumed less soda. Participants showed faster response times and higher accuracy on the soda-specific compared to neutral go/no-go . ERP results indicated inhibitory control was greater when individuals withheld dominant responses to soda stimuli rather than neutral stimuli. Neither N2 no-go amplitude on the soda-specific go/no-go nor P3 no-go amplitude on the soda-specific predicted measures of soda intake. Results suggest greater inhibitory control resources are required when withholding responses to soda beverages compared to neutral stimuli, but inhibitory control ERPs did not predict day-to-day soda intake.

Duration of an acute moderate-intensity exercise session affects approach bias toward high-calorie food among individuals with obesity

Obesity is partly driven by unhealthy eating behaviors underpinned by an approach bias toward high-calorie food. Although exercise is a useful strategy for weight loss among individuals with obesity, whether exercise modulates this approach bias is unclear. This study assessed whether the duration of an acute moderate-intensity exercise altered the approach bias toward high-calorie food among individuals with obesity. In total, 24 individuals with obesity were included in this study with a randomized, counterbalanced, crossover design. Participants completed three sessions of 30, 45, or 60 minutes of moderate-intensity exercise (40%-59% of heart rate reserve) on an elliptical trainer or completed a control rest session for 55 minutes. Food approach bias was evaluated using a joystick-based approach-avoidance task immediately before and after each session. Two-way repeated-measures analysis of variance was used to analyze the data. We found that compared with that before exercise, the approach bias score toward high-calorie food was significantly decreased only in the 45-minute exercise session (p = .015) and that this score was also significantly lower than that after both the 60-minute exercise session (p = .002) and the control session (p = .024). These findings suggest a dose-response relationship between exercise duration and approach bias, with 45 minutes of moderate-intensity exercise being an effective strategy for decreasing the approach bias toward high-calorie food among individuals with obesity.

Exercise Increases Attentional Bias Towards Food Cues in Individuals Classified as Overweight to Obese

BACKGROUND

The obesity epidemic continues to be a major public health concern. Although exercise is the most common weight loss recommendation, weight loss outcomes from an exercise program are often suboptimal. The human body compensates for a large percentage of the energy expended through exercise to maintain energy homeostasis and body weight. Increases in energy intake appear to be the most impactful compensatory behavior. Research on the mechanisms driving this behavior has not been fully elucidated.

PURPOSE

To determine if exercise influences the attentional processing towards food cues (attentional bias) and inhibitory control for food cues among individuals classified as overweight to obese who do not exercise.

METHODS

Thirty adults classified as overweight to obese participated in a counterbalanced, crossover trial featuring two assessment visits on separate days separated by at least one week. Attentional bias and inhibitory control towards food cues was assessed prior to and after a bout of exercise where participants expended 500 kcal (one assessment visit) and before and after a 60 min bout of watching television (second assessment visit). Attentional bias was conceptualized as the percentage of time fixated on food cues when both food and neutral (non-food) cues were presented during a food-specific dot-probe task. Inhibitory control, specifically motor impulsivity, was assessed as percentage of inhibitory failures during a food-specific Go/NoGo task.

RESULTS

A significant condition by time effect was observed for attentional bias towards food cues, independent of hunger, whereas attentional bias towards food cues was increased pre-post exercise but not after watching TV. Inhibitory control was not affected by exercise or related to attentional bias for food cues.

CONCLUSIONS

An acute bout of exercise increased attentional bias for food cues, pointing to a mechanism that may contribute to the weight loss resistance observed with exercise. Future trials are needed to evaluate attentional bias towards food cues over a longitudinal exercise intervention.

The impact of exercise intensity on neurophysiological indices of food-related inhibitory control and cognitive control: A randomized crossover event-related potential (ERP) study

Food-related inhibitory control, the ability to withhold a dominant response towards highly palatable foods, influences dietary decisions. Food-related inhibitory control abilities may increase following a bout of aerobic exercise; however, the impact of exercise intensity on both food-related inhibitory control and broader cognitive control processes is currently unclear. We used a high-powered, within-subjects, crossover design to test how relative intensity of aerobic exercise influenced behavioral (response time, accuracy) and neural (N2 and P3 components of the scalp-recorded event-related potential [ERP]) measures of food-related inhibitory and cognitive control. Two hundred and ten participants completed three separate conditions separated by approximately one week in randomized order: two exercise conditions (35% VO_2max or 70% VO_2max) and seated rest. Directly following exercise or rest, participants completed a food-based go/no-go task and a flanker task while electroencephalogram data were recorded. Linear mixed models showed generally faster response times (RT) and improved accuracy following 70% VO_2max exercise compared to rest, but not 35% VO_2max; RTs and accuracy did not differ between 35% VO_2max exercise and rest conditions. N2 and P3 amplitudes were larger following 70% VO_2max exercise for the food-based go/no-go task compared to rest and 35% VO_2max exercise. There were no differences between exercise conditions for N2 amplitude during the flanker task; however, P3 amplitude was more positive following 70% VO_2max compared to rest, but not 35% VO_2max exercise. Biological sex did not moderate exercise outcomes. Results suggest improved and more efficient food-related recruitment of later inhibitory control and cognitive control processes following 70% VO_2max exercise.

Using generalizability theory and the ERP reliability analysis (ERA) toolbox for assessing test-retest reliability of ERP scores part 2: Application to food-based tasks and stimuli

If an ERP score is to reflect a trait-like characteristic or indicate if an intervention had an effect over time, adequate internal consistency and test-retest reliability of that ERP score across multiple testing sessions must be established. The current paper is a companion paper to Clayson et al. (current issue) that applied generalizability theory formulas and the ERP Reliability Analysis (ERA) Toolbox to assess test-retest and internal consistency in a dataset of event-related brain potentials (ERPs) assessing food-related cognition. Although ERPs in response to food cues have been related to eating behaviors or assessed during a health intervention, the reliability of food-related ERPs generally has not been tested. Within the generalizability theory framework, we assessed the stability (cf., test-retest reliability) and equivalence (cf., internal consistency) of four commonly used food-related ERPs: the late positive potential (LPP), centro-parietal P3, N2, and fronto-central P3. 132 participants (92 female) completed two testing sessions held two weeks apart. During the sessions, participants completed a passive food viewing task, a high-calorie go/no-go task, and a low-calorie go/no-go task in a counterbalanced fashion. Coefficients of equivalence for all ERPs were excellent (>0.96). Coefficients of stability were moderate-to-low, with N2 scores on the low-calorie go/no-go task showing the highest test-retest reliability (>0.65) and fronto-central P3 scores on the high-calorie go/no-go task showing the lowest (0.48). Results suggest the ERPs in the current dataset have high internal consistency and would be reliable in detecting individual differences, but their test-retest reliability is limited. Reliability of these ERPs may be improved with changes in task stimuli, task instructions, and study procedures.

Do Food Odors Differently Influence Cerebral Activity Depending on Weight Status? An Electroencephalography Study of Implicit Olfactory Priming Effects on the Processing of Food Pictures

Attentional automatic processes and cerebral activity may differ between individuals with different weight statuses in the presence of food stimuli (e.g. odors, pictures). In the present study, we used an implicit olfactory priming paradigm to test the influence of non-attentively perceived food odors on the cerebral activity underlying the processing of food pictures, in normal-weight, overweight, and obese adults. A pear odor and a pound cake odor were used as primes, respectively priming sweet low-energy-density foods and high-energy-density foods. Event-related potentials were recorded while the participants passively watched pictures of sweet low and high-energy-density foods, under the two priming conditions plus an odorless control condition. The amplitude and latency of several peaks were measured (P100, N100, P200, N400). As a major result, we found that weight status influences the cerebral activity underlying the processing of food cues outside of consciousness, as early as the first detectable P100 peak.

The association between healthy lifestyle score with cardiorespiratory fitness and muscle strength

OBJECTIVE

The association of individual behaviours such as diet, tobacco use, body mass index (BMI) and physical activity have been investigated separately in relevance to cardiorespiratory fitness (CRF) and muscle strength. The purpose of this study is to investigate the combined association of the four mentioned lifestyle factors with cardiorespiratory fitness and muscle strength.

METHODS

This cross-sectional study was conducted on 271 Iranian adults, aged 18-70 years. We developed a healthy lifestyle score (HLS) that ranged from 0 to 103 (higher score reflecting better adherence to healthier lifestyle) and included four lifestyle behavioural components (diet, physical activity, smoking and BMI). The relationship between HLS, CRF and muscle strength was determined using linear and non-linear regression analysis.

RESULTS

HLS score was not significantly associated with VO_2max (mL/kg/min) P = .43; VO_2max (L min) P = .14; VO_2max (LBM) (P = .79) and mean muscle strength (MMS) (kg) (P = .11), muscle strength of right hand (MSR) (kg) (P = .10) and muscle strength of left hand (MSL) (kg) (P = .16) in the unadjusted model. After adjustment for potential confounders, we found a significant association between HLS and Vo_2max (L/min), MMS (kg), MSR (kg) and MSL (kg) (P < .001 for all). Also HLS and MMS (r = .06, P = .31), MSR (r = .07, P = .25), MMS (r = .05, P = .39), VO_2max (mL/kg/min) (r = .01, P = .77), VO_2max (L min) (r = .05, P = .35) and VO_2max (LBM) (r = .002, P = .91) have no statistically significant linear relationship.

CONCLUSION

Adherence to healthy lifestyle may be associated with increased CRF and muscle strength after adjusting for potential confounding variables.

A Comparison of Intermittent and Continuous Exercise Bouts at Different Intensities on Appetite and Postprandial Metabolic Responses in Healthy Men

Exercise intensity affects many potential postprandial responses, but there is limited information on the influence of exercise modality. Therefore, the aim of this study was to investigate if the nature of exercise at two different intensities would affect gastric emptying rate (GER), appetite and metabolic responses following ingestion of a semi-solid meal. Twelve healthy men completed, in a random order, four 60-min cycles at 60% VO_2peak (MOD), 40% VO_2peak (LOW) and in a continuous (CON) or intermittent (INT) manner. INT consisted of 20 × 1-min exercise bouts with 2-min rest breaks. INT and CON were matched for total work output at each intensity. GER of the post-exercise meal was measured for 2 h using the 13C-breath method. Blood glucose, substrate utilisation and appetite ratings were measured at regular intervals throughout all trials and 24-h energy intake (EI) post-trials was assessed. GER-Delta over Baseline (DOB) was lower (p < 0.05) on MOD-INT vs. MOD-CON from 30–120 min post-meal. Blood glucose was higher mid-exercise (p < 0.05) on MOD-INT vs. MOD-CON. Although post-exercise LOW-CON was significantly higher than LOW-INT (p < 0.05), blood glucose was also higher 30-min post-meal ingestion on both CON trials compared to INT (p < 0.001). No interaction effect was observed for perceived appetite responses 2 h after meal ingestion (all p > 0.05). 24-h post-trial EI was similar between LOW-CON vs. LOW-INT (p > 0.05), although MOD-INT vs. MOD-CON 3500 ± 1419 vs. 2556 ± 989 kCal: p < 0.001 was elevated. In summary, MOD-INT exercise delays GER without stimulating perceived appetite in the 2 h period after meal ingestion, although EI was greater in the 24-h post-trial.

Association of Adherence to Specific Mediterranean Diet Components and Cardiorespiratory Fitness in Young Adults

OBJECTIVE

Cardiorespiratory fitness (CRF) and a healthy diet may be part of an overall healthy lifestyle. The association between cardiorespiratory fitness and adherence to an overall Mediterranean Diet (MedD) pattern and specific MedD foods has been assessed.

DESIGN

Subjects completed a lifestyle survey and dietary pattern, using the validated MedD Adherence 14-item questionnaire and two self-reported 24-h dietary recalls. Participants' height, body weight, waist circumference (WC), and CRF (maximum oxygen uptake, VO2max, ml/kg/min) were measured.

SETTING

University of Cádiz, Spain.

SUBJECTS

A sample of young adults (n = 275, 22.2 ± 6.3 years).

RESULTS

Mean VO2max was 43.9 mL/kg/min (SD 8.5 mL/kg/min). Most participants had healthy CRF (75.9%). The average MedD score was 6.2 points (SD 1.8 points). Participants who consumed more servings of nuts had higher VO2max. Those who showed low CRF performed less physical activity (PA) and had a higher body mass index (BMI) and WC compared with those classified as having healthy CRF. Nut consumption was positively associated with VO2max (β = 0.320; 95% CI 2.4, 10.7; p < 0.002), adjusting for sex, age, smoking PA, BMI, WC, and energy intake, showing the subjects who consumed more nuts were fitter than young adults who consumed less.

CONCLUSIONS

CRF is positively associated with nut consumption but not with the overall MedD pattern and all other MedD foods in the young adults. The subjects who consumed more servings of nuts were fitter than young adults who consumed less. Moreover, fitter subjects performed more PA and had a lower BMI and WC than those who had lower fitness levels.

Acute coordinative exercise ameliorates general and food-cue related cognitive function in obese adolescents

Whether the acute coordinative exercise could affect the inhibitory control and food-cue related attention in obese adolescents remains understudied. Therefore, this study used the Stroop test and the food-cue related Stroop test to explore the impacts of 20 min of acute coordinative exercise on the cognitive tests involving inhibitory control and attentional bias towards food-cue related stimuli, respectively, in obese adolescents. Thirty-eight obese adolescents (mean age = 14.63 ± 0.69 years) were equally divided into exercise and control groups. The cognitive tests (i.e., the Stroop test and the food-cue related Stroop test) and hunger scores were conducted and assessed before and after an intervention. The exercise group had significantly larger negative pre-post response time difference in the congruent (-1.04 ± 0.29 ms) and incongruent (-5.76 ± 1.66 ms) conditions of the Stroop test than the control group (ps < 0.01), and a smaller post-interference (1.13 ± 0.14) than the pre-interference (1.31 ± 0.14, p = 0.04). Moreover, a significantly larger negative pre-post response time difference on the food-cue related Stroop test was observed in the exercise group (-4.42 ± 7.20 ms) than the control group (1.76 ± 8.37 ms, p = 0.02). Collectively, an acute coordinative exercise session could induce superior inhibitory control and less attentional bias towards food-cue related stimuli in obese adolescents.

Neural responses to food stimuli among individuals with eating and weight disorders: a systematic review of event-related potentials

A systematic review was conducted to investigate event-related potentials (ERPs) in response to food and non-food stimuli among individuals with eating and weight disorders. Limiting the search to studies that have analysed ERPs relating to motivated attention and inhibitory control, 19 research papers were extracted from a systematic search in PubMed, Ovid, and Web of Science (2000-2018). An enhanced attentional bias towards food over non-food images (as indexed by P3(00) and LPP amplitudes) was evident for all populations. Individuals with binge eating disorder showed an enhanced attentional response to food cues compared to healthy controls. Inhibitory control-related ERP components (N2(00) and P3a) increased during food-specific no-go trials, but did not differentiate overweight from 'healthy' weight groups. The N2 amplitude to food pictures were positively correlated with caloric intake and food craving among individuals with obesity and binge eating disorder, respectively, while P3(00) was sensitive to hunger levels among overweight and obese females. The heterogeneity of stimuli/paradigms adopted, component timescales extracted, ERPs analysed, and data presented has challenged this review's ability to produce a robust synthesis of results. Some recommendations for future research are discussed.

Brain reactivity to visual food stimuli after moderate-intensity exercise in children

Exercise may play a role in moderating eating behaviors. The purpose of this study was to examine the effect of an acute bout of exercise on neural responses to visual food stimuli in children ages 8-11 years. We hypothesized that acute exercise would result in reduced activity in reward areas of the brain. Using a randomized cross-over design, 26 healthy weight children completed two separate laboratory conditions (exercise; sedentary). During the exercise condition, each participant completed a 30-min bout of exercise at moderate-intensity (~ 67% HR maximum) on a motor-driven treadmill. During the sedentary session, participants sat continuously for 30 min. Neural responses to high- and low-calorie pictures of food were determined immediately following each condition using functional magnetic resonance imaging. There was a significant exercise condition*stimulus-type (high- vs. low-calorie pictures) interaction in the left hippocampus and right medial temporal lobe (p < 0.05). Main effects of exercise condition were observed in the left posterior central gyrus (reduced activation after exercise) (p < 0.05) and the right anterior insula (greater activation after exercise) (p < 0.05). The left hippocampus, right medial temporal lobe, left posterior central gyrus, and right anterior insula appear to be activated by visual food stimuli differently following an acute bout of exercise compared to a non-exercise sedentary session in 8-11 year-old children. Specifically, an acute bout of exercise results in greater activation to high-calorie and reduced activation to low-calorie pictures of food in both the left hippocampus and right medial temporal lobe. This study shows that response to external food cues can be altered by exercise and understanding this mechanism will inform the development of future interventions aimed at altering energy intake in children.

Homeostatic and neurocognitive control of energy intake in response to exercise in pediatric obesity: a psychobiological framework

While energy intake and energy expenditure have long been studied independently, the alarming progression of obesity has led to a more integrative approach to energy balance considering their potential interactions. Although the available literature concerned with the effect of chronic and acute exercise on energy intake and appetite control in adults is considerable, these questions remain less explored among children and adolescents. Based on the search of four databases (Medline, Embase, PsycINFO and Cochrane Library; articles published until May 2018), the objective of this review is to summarize and discuss the effect of acute and chronic physical exercise on energy intake and appetite control in children and adolescents with obesity, and to identify the physiological and neurocognitive signals and pathways involved. Evidence suggested that acute intensive exercise has the potential to reduce subsequent energy intake in children and adolescents with obesity but not healthy weight, through both peripheral (mainly gastro-peptides) and neurocognitive (neural responses to food cues) pathways. The nutritional responses to chronic physical activity remain less clear and require further consideration, especially from an anti-obesity perspective.

Effects of an acute bout of physical exercise on reward functioning in healthy adults

Exercise has been proposed as a treatment for several psychiatric disorders. Exercise may act in part through beneficial effects on reward functioning, as it alters neurotransmitter levels in reward-related circuits. However, there has been little investigation of the effect of exercise on reward functions in humans. We hypothesized an acute bout of exercise would increase motivation for and pleasurable responses to rewards in healthy humans. In addition, we examined possible moderators of exercise's effects, including demographics, fitness and previous exercise experience. Thirty-five participants completed exercise and sedentary control sessions in randomized, counterbalanced order on separate days. Immediately after each activity, participants completed measures of motivation for and pleasurable responses to rewards, consisting of willingness to exert effort for monetary rewards and subjective responses to emotional pictures. Exercise did not increase motivation or pleasurable responses on average. However, individuals who had been running for more years showed increases in motivation for rewards after exercise, while individuals with less years running showed decreases. Further, individuals with higher resting heart rate variability reported lower arousal in response to all emotional pictures after exercise, while individuals with low heart rate variability reported increased arousal in response to all emotional pictures after exercise. General fitness did not have similar moderating effects. In conclusion, acute exercise improved reward functioning only in individuals accustomed to that type of exercise. This suggests a possible conditioned effect of exercise on reward functioning. Previous experience with the exercise used should be examined as a possible moderator in exercise treatment trials.

Exercise following Mental Work Prevented Overeating

Mental work may promote caloric intake, whereas exercise may offset positive energy balance by decreasing energy intake and increasing energy expenditure.

PURPOSE

This study aimed to replicate previous findings that mental work increases caloric intake compared with a rest condition and assess whether exercise after mental work can offset this effect.

METHODS

Thirty-eight male and female university students were randomly assigned to mental work + rest (MW + R) or mental work + exercise (MW + E). Participants also completed a baseline rest (BR) visit consisting of no mental work or exercise. Visit order was counterbalanced. During the MW + R or MW + E visit, participants completed a 20-min mental task and either a 15-min rest (MW + R) or a 15-min interval exercise (MW + E). Each visit ended with an ad libitum pizza lunch. A two-way repeated-measures ANOVA was used to compare eating behavior between groups.

RESULTS

Participants in the MW + R condition consumed an average of 100 more kilocalories compared with BR (633.3 ± 72.9 and 533.9 ± 67.7, respectively, P = 0.02), and participants in MW + E consumed an average of 25 kcal less compared with BR (432.3 ± 69.2 and 456.5 ± 64.2, respectively, P > 0.05). When including the estimated energy expenditure of exercise in the MW + E conditions, participants were in negative energy balance by an average of 98.5 ± 41.5 kcal, resulting in a significant difference in energy balance between the two groups (P = 0.001).

CONCLUSION

An acute bout of interval exercise after mental work resulted in significantly decreased food consumption compared with a nonexercise condition. These results suggest that an acute bout of exercise may be used to offset positive energy balance induced by mental tasks.

Reduced neural responses to food cues might contribute to the anorexigenic effect of acute exercise observed in obese but not lean adolescents

Acute exercise has been found to reduce subsequent energy intake in obese adolescents. Although it has been suggested that some neural pathways are involved in this post-exercise energy intake regulation, it remains unknown whether the post-exercise attentional response to food cues differs as a function of weight status. We hypothesize that there will be a reduction in the neural response to food cues as a result of exercise in obese adolescents, but not in their lean counterparts. Fourteen obese and 14 lean adolescent boys (12-15 years) were randomized (within-subjects design) to remain seated (CON) or to exercise 45 minutes at 65% of their maximal capacities (EX). After the exercise or sitting period, the adolescents' cognitive engagement in the processing of food vs. non-food cues was assessed during an attentional computer-based task with electroencephalography (EEG) recording. An ad libitum lunch meal was offered and appetite feelings were assessed (visual analog scales). There was no main effect of condition on energy intake in lean subjects, but obese adolescents ate significantly less following EX compared with CON (P<.05). There was no effect of condition or stimulus type (food vs. non-food) on the EEG-recorded amplitude of the P3b component in lean adolescents. However, the response to food cues was significantly reduced compared with non-food stimuli after exercise in obese participants (P<.01). Following EX, but not CON, total body weight, body mass index, and fat mass were inversely correlated with the EEG response to food-non-food stimuli (all P<.05). However, this response was not associated with ad libitum EI (both P>.1). Acute exercise favors decreased neural response to food cues compared with non-food cues in obese but not lean adolescents, suggesting differential effects of exercise on the neural processing of food cues based on weight status.

Disparity in neural and subjective responses to food images in women with obesity and normal-weight women

OBJECTIVE

Self-reports tend to differ from objective measurements of food intake, particularly in adults with obesity; however, no studies have examined how neural responses to food (an objective measure) and subjective ratings of food differ by BMI status. This study tested normal-weight women (NWW) and women with obesity (OBW) for group differences in neural indices of attention towards food pictures, subjective ratings of these pictures, and the disparity between objective and subjective measurements.

METHODS

Twenty-two NWW (21.8 ± 1.7 kg/m² ) and 22 OBW (37.0 ± 5.7 kg/m² ) viewed food and flower pictures while late positive potential amplitude, an event-related potential, was recorded. Participants rated pictures for arousal and valence.

RESULTS

Late positive potential amplitude was larger toward food than flower pictures. OBW self-reported flower pictures as more pleasant than food; NWW showed no difference for pleasantness. There were no significant main effects or interactions for arousal. Standardized scores showed that only on subjective, but not objective, measures did OBW compared with NWW disproportionately indicate food pictures as less pleasant than flowers.

CONCLUSIONS

Compared with NWW, OBW showed larger discrepancies between neural and subjective reports of attention towards food. Inaccurate self-reports of attention towards food may reduce the efficiency of health interventions.

Posterior resting state EEG asymmetries are associated with hedonic valuation of food

Research on the hedonic value of food has been important in understanding the motivational and emotional correlates of normal and abnormal eating behaviour. The aim of the present study was to explore associations between hemispheric asymmetries recorded during resting state electroencephalogram (EEG) and hedonic valuation of food. Healthy adult volunteers were recruited and four minutes of resting state EEG were recorded from the scalp. Hedonic food valuation and reward sensitivity were assessed with the hedonic attitude to food and behavioural activation scale. Results showed that parieto-occipital resting state EEG asymmetries in the alpha (8-12Hz) and beta (13-30Hz) frequency range correlate with the hedonic valuation of food. Our findings suggest that self-reported sensory-related attitude towards food is associated with interhemispheric asymmetries in resting state oscillatory activity. Our findings contribute to understanding the electrophysiological correlates of hedonic valuation, and may provide an opportunity to modulate the cortical imbalance by using non-invasive brain stimulation methods to change food consumption.

Reduced Sleep Acutely Influences Sedentary Behavior and Mood But Not Total Energy Intake in Normal-Weight and Obese Women

Using a crossover design, 22 normal-weight and 22 obese women completed two free-living sleep conditions: (a) Normal Sleep: night of ~8 hr time in bed; and (b) Reduced Sleep: night of < 5 hr time in bed). Outcome measures were energy intake, physical activity and sedentary time, and mood. Sleep time was 7.7 ± 0.3 and 4.8 ± 0.2 hrs during the Normal Sleep and Reduced Sleep conditions, respectively (F = 1791.94; p < 0.0001). Energy intake did not differ between groups or as a function of sleep condition (F = 2.46; p = 0.1244). Sedentary time was ~ 30 min higher after the Reduced Sleep condition (F = 4.98; p = 0.0318); other physical activity outcomes were not different by condition (p > 0.05). Total mood score, depression, anger, vigor, fatigue, and confusion were worse after Reduced Sleep (p < 0.05). Reducing sleep acutely and negatively influenced sedentary time and mood in normal-weight and obese women.

Reduced neural response to food cues following exercise is accompanied by decreased energy intake in obese adolescents

BACKGROUND

Acute exercise has been found to favor a transient anorexigenic effect in obese adolescents. Although the role of some gastro-peptides has been suggested as an explanation for this observed reduced energy intake after exercise, it is unknown whether neural pathways involved in the regulation of food intake are modulated in youth.

METHODS

Body composition (dual-energy X-ray absorptiometry) and aerobic capacities were assessed in 19 obese adolescent boys. Participants were randomized to remain at rest in a sitting position (CON condition) or to exercise 45 min at 65% of their maximal capacities (EX condition) by the end of the morning. An attentional computer task with electroencephalography recording was completed immediately after the exercise or sitting period to measure an event-related component (P3b) reflecting the level of cognitive engagement in the processing of food cues. A lunch test-meal was offered ad libitum and appetite feelings assessed at regular intervals using visual analog scales.

RESULTS

The 45-min cycling exercise set at 65% VO2max induced a mean energy expenditure of 399±75 kcal. Both absolute (P<0.05) and relative (P<0.001) subsequent energy intake were significantly reduced after EX (1037±260 and 639±256 kcal, respectively) compared with CON (1116±243 and 1011±239 kcal, respectively). The energy ingested derived from each macronutrient and self-reported appetite remained unchanged. Although the amplitudes of the P3b component evoked by food and non-food visual stimuli were not significantly different during CON, the response to food cues was significantly reduced compared with non-food stimuli after exercise (P<0.01).

DISCUSSION

An acute exercise favors decreased neural response to food cues compared with non-food ones in obese adolescents that may contribute to their subsequently reduced energy intake.

Cardiorespiratory fitness is positively associated with a healthy dietary pattern in New Zealand adolescents

OBJECTIVE

To examine the association between cardiorespiratory fitness and dietary patterns in adolescents.

DESIGN

Food choice was assessed using the validated New Zealand Adolescent FFQ. Principal components analysis was used to determine dietary patterns. Trained research assistants measured participants' height and body mass. Cardiorespiratory fitness was assessed in a subset of participants using the multistage 20 m shuttle run. The level and stage were recorded, and the corresponding VO2max was calculated. Differences in mean VO2max according to sex and BMI were assessed using t tests, while associations between cardiorespiratory fitness and dietary patterns were examined using linear regression analyses adjusted for age, sex, school attended, socio-economic deprivation and BMI.

SETTING

Secondary schools in Otago, New Zealand.

SUBJECTS

Students (n 279) aged 14-18 years who completed an online lifestyle survey during a class period.

RESULTS

Principal components analysis produced three dietary patterns: 'Treat Foods', 'Fruits and Vegetables' and 'Basic Foods'. The 279 participants who provided questionnaire data and completed cardiorespiratory fitness testing had a mean age of 15·7 (sd 0·9) years. Mean VO2max was 45·8 (sd 6·9) ml/kg per min. The 'Fruits and Vegetables' pattern was positively associated with VO2max in the total sample (β=0·04; 95%CI 0·02, 0·07), girls (β=0·06; 95% CI 0·03, 0·10) and boys (β=0·03; 95% CI 0·01, 0·05).

CONCLUSIONS

These results indicate that increase in cardiorespiratory fitness was associated with a healthier dietary pattern, suggesting both should be targeted as part of a global lifestyle approach. Longitudinal studies are needed to confirm this association in relation to health outcomes in New Zealand adolescents.

The processing of food stimuli in abnormal eating: a systematic review of electrophysiology

To update the knowledge about attentional processing of food stimuli, a systematic review of electrophysiological studies was conducted using PubMed, PsychInfo and Web of Knowledge (2000-2014). Twenty-one studies were included into a qualitative synthesis. Presentation of food and control pictures was used to analyze event-related potentials related to sensory processing and motivated attention. Results show consistent attentional bias towards food pictures compared with neutral pictures for patient and control groups. Group comparisons between individuals with abnormal-eating and healthy-eating participants were more inconsistent. Results suggest that temporal differences in the millisecond range are essential for the understanding of visual food processing. In obesity, early attention engagement to food is followed by relatice disengagement. Loss of control eating, as well as external and emotional eating, are associated with a sustained maintenance of attention towards high-caloric food. There is a lack of studies in anorexia nervosa, bulimia nervosa and binge eating disorder.

Creating an acute energy deficit without stimulating compensatory increases in appetite: is there an optimal exercise protocol?

Recent years have witnessed significant interest from both the scientific community and the media regarding the influence of exercise on subsequent appetite and energy intake responses. This review demonstrates a consensus among the majority of scientific investigations that an acute bout of land-based endurance exercise does not stimulate any compensatory increases in appetite and energy intake on the day of exercise. Alternatively, preliminary evidence suggests that low volume, supramaximal exercise may stimulate an increase in appetite perceptions during the subsequent hours. In accordance with the apparent insensitivity of energy intake to exercise in the short term, the daily energy balance response to exercise appears to be primarily determined by the energy cost of exercise. This finding supports the conclusions of recent training studies that the energy expenditure of exercise is the strongest predictor of fat loss during an exercise programme.

Restricting night-time eating reduces daily energy intake in healthy young men: a short-term cross-over study

Few experimental data are available to support the notion that reducing night-time eating changes total daily energy intake (EI) or body weight in healthy adults. The present study primarily examined the short-term effect of night eating restriction (NER) on daily EI in healthy young men. It secondarily examined body weight and moods associated with NER. Using a cross-over design, twenty-nine men (20·9 (sd 2·5) years; 24·4 (sd 2·5) kg/m²) initiated a 2-week NER intervention (elimination of EI from 19.00 to 06.00 hours) and a 2-week control condition, counterbalanced and separated by a 1-week washout period. EI and macronutrient intake were assessed using computerised, multiple-pass 24 h food recalls, body weight via a digital scale and mood using the Profile of Mood States survey. Of the twenty-nine participants, twenty-seven (93 %) completed all aspects of the study. During the NER condition, the participants consumed less total energy per d than during the control condition (10 125 v. 11 146 kJ/d; F= 6·41; P= 0·018). During the NER condition, no energy was reported consumed between 19.00 and 06.00 hours; however, during the control condition, the energy intake of participants was 2920 (sd 1347) kJ/d between 19.00 and 06.00 hours. There was a significant difference in weight change between the NER (-0·4 (sd 1·1) kg) and control (+0·6 (sd 0·9) kg) conditions (F= 22·68; P< 0·001). Differences in total mood score or mood subscales between the NER and control conditions were not apparent (P>0·05). These findings provide support for NER decreasing short-term EI in healthy young men.