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Low levels of brain derived-neurotrophic factor (BDNF) and excessive screen exposure are risk factors for neurocognitive deficits and obesity in youth, but the relationship between screen time and BDNF remains unknown. This study examined whether duration and/or type of sedentary screen time behaviour (TV viewing, video games, recreational computer use) are associated with serum BDNF levels in youth with obesity. The sample consisted of 250 inactive, postpubertal adolescents with obesity (172 females/78 males, aged 15.5 ± 1.4 years) at the baseline assessment of the Healthy Eating, Aerobic, Resistance Training in Youth Study. After controlling for self-reported age, sex, race, parental education, puberty stage, physical activity, and diet, higher total screen exposure was significantly associated with lower serum BDNF levels (β = −0.21, p = 0.002). TV viewing was the only type of screen behaviour that was associated with BDNF levels (β = −0.22, p = 0.001). Higher exposure to traditional forms of screen time was independently associated with lower serum BDNF levels, and this association appears to be driven primarily by TV viewing. Future intervention research is needed to determine whether limiting screen time is an effective way to increase BDNF and associated health benefits in a high-risk population of youth with obesity. Trial Registration: ClinicalTrials.Gov NCT00195858. Novelty: This study is the first to show that recreational screen time is inversely associated with serum BDNF levels. The inverse association between screen time and BDNF is driven primarily by TV viewing, indicating the type of screen might matter.

Olfaction contributes to feeding behaviour and is modulated by changes in dopamine levels. Methylphenidate (MPH) increases brain dopamine levels and has been shown to reduce appetite and promote weight loss in patients with attention deficit hyperactivity disorder. The objectives of this study were to test the effect of MPH on olfaction, appetite, energy intake, and body weight (BW) on individuals with obesity. In a randomized, double-blind study, 12 participants (age 28.9 ± 6.7 years) with a body mass index (BMI) of 36.1 ± 4.5 kg/m2 were assigned to MPH (0.5 mg/kg) (n = 5) or placebo (n = 7) twice daily for 2 months. Appetite (visual analog scale), odour threshold (Sniffin’ Sticks®), energy intake (food menu), and BW (DEXA scan) were measured at day 1 and day 60. MPH intake significantly increased odour threshold scores (6.3 ± 1.4 vs. 9.4 ± 2.1 and 7.9 ± 2.3 vs. 7.8 ± 1.9, respectively; p = 0.029) versus placebo. There was a significantly greater suppression of appetite sensations (desire to eat (p = 0.001), hunger (p = 0.008), prospective food consumption (p = 0.003)) and an increase in fullness (p = 0.028) over time in the MPH versus placebo. MPH suppressed appetite and improved olfactory sensitivity in individuals with obesity. These data provide novel findings on the favourable effects of MPH on appetite and weight regulation in individuals living with obesity.

The relationship between reading ability and health, known as health literacy, broadly reflects the skills and competencies required to operate within the healthcare environment. It is only recently that we have seen attempts to conceptualize health literacy in the context of medication use by using terms such as medication literacy. Health literacy changes over one's lifetime and is dependent on factors such as numeracy, education, income, gender and country. Low health literacy and low medication literacy have been identified as significant risk factors for poor health outcomes of adults and children. With an evaluation of common tools used to assess health literacy and medication literacy, the aim of this review is to describe the shared responsibility between patients and healthcare providers for the communication of health and medication information. Key strategies and interventions to improve two-way communication between patients and healthcare providers are highlighted, with a focus on how health literacy can impact child health outcomes.

Background: Medical cannabis has been increasingly used in Canada after being sanctioned by Health Canada in 2001. Insomnia and sleep disorders are among the most common conditions for which patients report using cannabis. Current research shows cannabis may have a beneficial effect in sleep disorders and may improve patient-reported sleep scores. Methods: A retrospective chart review was conducted at Hybrid Pharm community pharmacy in Ottawa, Ontario, and included patients who were interested in, or already using, medical cannabis for sleep disorders. A qualitative, exploratory approach was taken to evaluate the descriptive efficacy and safety of medical cannabis when prescribed for insomnia or comorbid conditions. The comprehensive data collection also involved investigating the impact of cannabis on other medication used for insomnia. Results: A total of 38 patients were identified as having adequate follow-up documentation to assess the impact of medical cannabis. At time of data collection, 15 patients (39%) were able to reduce or completely discontinue a prescription medication indicated for sleep. On follow-up, 27 patients (71%) reported a subjective improvement in their sleep or related condition. Only 8 patients (21%) reported any adverse effects from medical cannabis use, and these were manageable and did not require discontinuation of cannabis. Conclusion: This study highlights the importance of a pharmacist’s role in the management of cannabis-based therapy, including ongoing supportive care, follow-up and medication management. Can Pharm J (Ott) 2022;155:xx-xx.

Background The genetics of binge-eating disorder (BED) is an emerging topic, with dopaminergic genes being implicated in its etiology due to the role that dopamine (DA) plays in food reward sensitivity and self-regulation of eating behavior. However, no study to date has examined if DA genes influence response to behavioral treatment of BED. Objective The primary objective of this study was to examine the ability of DA-associated polymorphisms to predict BED treatment response measured using binge frequency over 12 months. As secondary objectives, this study examined cross-sectional relationships between these polymorphisms and anthropometrics in women living with and without BED and obesity. Methods Women aged 18–64 years old were genotyped for the DA-related SNPs DRD2/ANKK1 Taq1A (rs1800497) and COMT (rs4680), as well as the DA-related uVNTRs DAT-1 (SLC6A3) and MAO-A. A multi-locus DA composite score was formed from these 4 polymorphisms using genotypes known to have a functional impact resulting in modified DA signaling. Binge frequency (Eating Disorder Examination – Interview) and body composition (Tanita BC-418) were assessed in a pre-post analysis to examine genetic predictors of treatment response in women living with obesity and BED. Secondary data analysis was conducted on a cross-sectional comparison of three groups of women enrolled in trial group treatment for BED: women living with obesity and BED (n = 72), obesity without BED (n = 27), and normal-weight without BED (n = 45). Results There were no significant genotype × time interactions related to anthropometrics or binge frequency for any individual DA genotypes, or to the composite score reflecting DA availability. At baseline, there were no significant between-group differences in frequencies of DA-related alleles, nor were there associations between genotypes and anthropometrics. Conclusions Our study found no evidence to suggest that the DRD2/ANKK1 Taq1A, COMT, MAO-A, or DAT-1 polymorphisms are associated with response to behavioral intervention for BED as measured by changes in binge frequency. Future studies should examine a greater variety of dopaminergic polymorphisms, other candidate genes that target other neurotransmitter systems, as well as examine their impact on both behavioral and pharmacological-based treatment for BED.

Summary Background Childhood and adolescence are crucial periods for brain development, and the behaviours during a typical 24 h period contribute to cognitive performance. The Canadian 24-Hour Movement Guidelines for Children and Youth recommend at least 60 min physical activity per day, 2 h or less recreational screen time per day, and 9–11 h sleep per night in children aged 8–11 years. We investigated the relationship between adherence to these recommendations and global cognition. Methods In this cross-sectional observational study, we obtained data from the first annual curated release of the Adolescent Brain Cognitive Development study, a 10-year longitudinal, observational study. Data were collected from 21 study sites across the USA between Sept 1, 2016, and Sept 15, 2017. The participants were 4524 US children aged 8–11 years from 20 study sites. Exposures of interest were adherence to the physical activity, recreational screen time, and sleep duration guideline recommendations. The primary outcome was global cognition, assessed with the NIH Toolbox (National Institutes of Health, Bethesda, MD, USA), which we analysed with multivariable linear mixed-effects models to examine the relations with movement behaviour variables. Findings Complete movement behaviour data were available for 4520 participants. The mean number of guideline recommendations met was 1·1 (SD 0·9). Overall, 2303 (51%) participants met the sleep recommendation, 1655 (37%) met screen time, and 793 (18%) met the physical activity recommendation. 3190 (71%) participants met at least one recommendation, whereas 216 (5%) of participants met all three recommendations. Global cognition was positively associated with each additional recommendation met (β=1·44, 95% CI 0·82–2·07, p Interpretation Meeting the 24 h movement recommendations was associated with superior global cognition. These findings highlight the importance of limiting recreational screen time and encouraging healthy sleep to improve cognition in children. Funding National Institutes of Health.

Background Maternal prenatal smoking is associated with downstream childhood obesity. Although animal research suggests reduced resting energy expenditure (REE), decreased physical activity (PA), and increased energy intake as mechanisms, these relationships are unclear in humans. The objectives were to examine the association of prenatal maternal smoking with non-volitional energy expenditure (REE and the thermic effect of feeding [TEF]), child adiposity, energy intake, free-living PA (daily light PA (LPA), daily moderate-to-vigorous PA (MVPA), daily sedentary behavior (SB)), and screen time (television and computer/video game) in children. Methods As part of a longitudinal study, 46 children (n = 27 controls and n = 19 smoking exposed) with mean age 7.6 ± 2 years were recruited. Body weight and composition (Bioelectrical Impedance), height (Stadiometer), waist circumference (cm; tape), BMI (kg/m2), REE (kcal/day; indirect calorimetry), PA (minutes; Accelerometry), screen time (hours; self-report) and ad libitum energy intake (lunch buffet; 7-day food log) were measured. Effects sizes were evaluated using Cohen's d. Results Relative to controls, after controlling for age and family income, children who were exposed to cigarette smoke in utero exhibited greater waist circumference (p = 0.04, Cohen's d = 1.03), percent body fat (%BF; p = 0.02, Cohen's d = 0.97), and a trend for BMI (p = 0.05, Cohen's d = 0.86). Exposed children did not differ in REE (trend for lower: p = 0.1, Cohen's d = 0.42) or TEF but were shown to have significantly higher ad libitum energy intake (p = 0.02, Cohen's D = 0.70) from the palatable lunch buffet, but not from the out of laboratory 7-day energy intake (p = 0.8). Examining screen time behaviors, exposed children spent more time watching television during the week (p = 0.03, Cohen's D = 0.82), and overall television watching (p = 0.02, Cohen's D = 0.80); there were no group differences in any other screen time behaviors. Conclusions Children exposed to cigarette smoke in utero exhibit greater adiposity, and this exposure may have as contributing factors higher screen time, ad libitum energy intake, and a trend for reduced REE. The data suggest that lifestyle factors such as diet and screen time represent targets for obesity prevention in a high-risk population of young children exposed to prenatal cigarette smoke. Findings also highlight the need for smoking cessation programs to reduce downstream obesity in offspring.

Brain derived neurotrophic factor (BDNF) is a protein that plays a critical role in modulating cognition in animals and humans. Aerobic exercise often increases BDNF in adults, but effects of this exercise modality and others among adolescents remain uncertain. This study examined the effects of aerobic training, resistance training, and combined training on resting serum BDNF levels in adolescents with overweight and obesity. After a 4-week pre-randomization treatment, 304 post-pubertal, adolescents with overweight or obesity (70% females) aged 14–18 years were randomized to one of four groups for 22 weeks: aerobic training (N = 75), resistance training (N = 78), combined aerobic and resistance training (N = 75), or non-exercising control (N = 76). All participants received dietary counseling targeting a daily energy deficit of 250 kcal. The exercise prescription was 4 times per week, progressing to 45 min/session for the aerobic and resistance groups and 90 min/session for the combined group. Resting serum BDNF levels were measured at baseline and 6-months. Results showed that in both intention-to-treat (ITT) and per protocol (≥70% adherence to prescribed sessions) analyses, there were no significant within- or between-group changes in BDNF. Findings indicate that aerobic training, resistance training or their combination did change serum BDNF levels in adolescents with overweight and obesity. Trial Registration: ClinicalTrials.Gov NCT00195858 http://clinicaltrials.gov/show/NCT00195858, September 12, 2005 (Funded by the Canadian Institutes of Health Research).

Background This study preliminarily examined the relationship between physical activity, sedentary time, and social emotional functioning in children aged 4–6 years. Methods Eighty children attending kindergarden classes in Ottawa, Canada wore Actical accelerometers for 1-week to directly assess their physical activity and sedentary time. Physical activity was quantified as minutes per day in light intensity or moderate intensity, and steps per day, while sedentary time was quantified as minutes per day. Social emotional functioning attributes were assessed by teachers using the Devereux Students Strengths Assessment. Results After controlling for age, sex, household-income and school clustering using multilevel regression models, steps per day were positively associated with social awareness β = 1.537, CI = 0.115–2.959) self-awareness (β = 1.285, CI = 0.014–2.555), relationship skills (β = 1.729, CI = 0.238–3.219), personal responsibilities (β = 1.689, CI = 0.101–3.276), and optimistic thinking (β = 1.091, CI = 0.251–2.157). Moderate physical activity was positively associated with relationship skills (β = 1.598, CI = 0.065–3.131) and optimistic thinking (β = 1.515, CI = 0.069–2.234). Time spent in light physical activity and sedentary time were not associated with social emotional functioning indicators. Conclusions Physical activity as measured by steps per day and time spent in moderate physical activity was associated with better social emotional functioning. Future research is needed to verify these preliminary findings and determine the directionality of relationships observed, and experimental studies are needed to determine whether promoting either increased steps per day or intensity of physical activity can improve social emotional functioning in the early years.

This review examines human feeding behavior in light of psychological motivational theory and highlights the importance of midbrain dopamine (DA). Prospective evidence of both reward surfeit and reward deficit pathways to increased body weight are evaluated, and we argue that it is more complex than an either/or scenario when examining DA's role in reward sensitivity, eating, and obesity. The Taq1A genotype is a common thread that ties the contrasting models of DA reward and obesity; this genotype related to striatal DA is not associated with obesity class per se but may nevertheless confer an increased risk of weight gain. We also critically examine the concept of so-called food addiction, and despite growing evidence, we argue that there is currently insufficient human data to warrant this diagnostic label. The surgical and pharmacological treatments of obesity are discussed, and evidence is presented for the selective use of DA-class drugs in obesity treatment.

This study examined the effects of aerobic and resistance training, and their combination on health-related quality of life (HRQoL) in adolescents with overweight or obesity. After a 4-week run-in period, 304 (91 males, 213 females) post-pubertal adolescents aged 14–18 years, were randomized to 4 groups for 22 weeks of: aerobic training (n = 75), resistance training (n = 78), combined aerobic and resistance training (n = 75), or nonexercising control (n = 76). All participants received dietary counseling with a daily energy deficit of 250 kcal. Indicators of HRQoL such as overall HRQoL, and physical and psychosocial (an aggregate of emotional, social, and school functioning) HRQoL at baseline and 6 months postintervention were measured by the Pediatric Quality of Life questionnaire. The trial began in March 2005 and was completed in June 2011. In the intention-to-treat analyses, all groups showed significant improvements at 6 months on all HRQoL indicators. The aerobic group showed greater improvements than controls on physical HRQoL (mean differences of 5.5; 95% CI; 1.4–9.6, p = 0.009). In participants with ≥70% adherence, combined training produced greater improvements than control on overall HRQoL (mean differences of 4.8, 95% CI; 0.7–9.0, p = 0.02), physical HRQoL (mean differences of 5.8; 95% CI: 0.6–10.7; p = 0.03), social HRQoL (mean differences of 7.6; 95% CI: 1.0–14.2; p = 0.02), and school-based HRQoL (mean differences of 7.6; 95% CI: 1.0–14.2; p = 0.02). These findings highlight the potential importance of including resistance exercise into traditional aerobic exercise programs to maximize HRQoL in adolescents with obesity.

There has been renewed interest in examining the relationship between specific components of energy expenditure and the overall influence on energy intake (EI). The purpose of this cross-sectional analysis was to determine the strongest metabolic and anthropometric predictors of EI. It was hypothesized that resting metabolic rate (RMR) and skeletal muscle mass would be the strongest predictors of EI in a sample of overweight and obese adolescents. 304 post-pubertal adolescents (91 boys, 213 girls) aged 16.1 (±1.4) years with body mass index at or above the 95th percentile for age and sex OR at or above the 85th percentile plus an additional diabetes risk factor were measured for body weight, RMR (kcal/day) by indirect calorimetry, body composition by magnetic resonance imaging (fat free mass (FFM), skeletal muscle mass, fat mass (FM), and percentage body fat), and EI (kcal/day) using 3 day food records. Body weight, RMR, FFM, skeletal muscle mass, and FM were all significantly correlated with EI (p < 0.005). After adjusting the model for age, sex, height, and physical activity, only FFM (β = 21.9, p = 0.007) and skeletal muscle mass (β = 25.8, p = 0.02) remained as significant predictors of EI. FFM and skeletal muscle mass also predicted dietary protein and fat intake (p < 0.05), but not carbohydrate intake. In conclusion, with skeletal muscle mass being the best predictor of EI, our results support the hypothesis that the magnitude of the body’s lean tissue is related to absolute levels of EI in a sample of inactive adolescents with obesity.

Obese adolescents spend a disproportionate time in screen-based activities and are at higher risk for clinical depression compared to their normal-weight peers. While screen time is associated with obesity and cardiometabolic risk factors, little is known about the relationship between screen time and mental health. This cross-sectional study examines the association between duration and types of screen time and depressive symptomatology (subclinical symptoms) in a sample of 358 (261 female; 97 male) overweight and obese adolescents aged 14-18 years. Self-report measures assessed depressive symptoms and time spent in different types of screen behavior (TV, recreational computer use, and video games). After controlling for age, ethnicity, sex, parental education, body mass index (BMI), physical activity, caloric intake, carbohydrate intake, and intake of sugar-sweetened beverages, total screen time was significantly associated with more severe depressive symptomatology (β = 0.21, p = 0.001). After adjustment, time spent playing video games (β = 0.13, p = 0.05) and recreational computer time (β = 0.18, p = 0.006) was associated with depressive symptoms, but TV viewing was not.Screen time may represent a risk factor or marker of depressive symptomatology in obese adolescents. Future intervention research should evaluate whether reducing screen exposure reduces depressive symptoms in obese youth, a population at increased risk for psychological disorders.• Screen time is associated with an increased risk of obesity in youth. • Screen time is associated with an adverse cardio-metabolic profile in youth. What is New: • Screen time is associated with more severe depressive symptoms in overweight and obese adolescents. • Time spent in recreational computer use and playing video games, but not TV viewing, was associated with more severe depressive symptoms in overweight and obese adolescents.

Objectives The genetics of binge-eating disorder (BED) is an emerging topic and one candidate pathway, namely the fat mass and obesity-associated (FTO) gene, may be implicated because of its role in food reward sensitivity and self-regulation of eating. The aims of this study were to examine the independent effects of variants of FTO on binge frequency in women with and without BED and to examine the moderating role of interpersonal attachment in this association. Methods Secondary data analysis was conducted on a cross-sectional comparison of three groups of women in a trial of group treatment for BED: BED with obesity (n = 73), BED without obesity (n = 55), and normal weight without BED (n = 50). Women were genotyped for five of the most common FTO single-nucleotide polymorphisms, rs9939609, rs8050136, rs3751812, rs1421085, and rs1121980, which have been related to body mass index and energy intake. Binge frequency (Eating Disorder Examination), body composition (bioelectric impedance), and attachment (Attachment Style Questionnaire) were assessed. Results There were no significant between-group differences for frequencies of FTO alleles, nor were there any significant anthropometric associations. The FTO × attachment interaction was significant whereby, relative to a low-risk FTO genotype, individuals with a high-risk genotype for the SNP rs1421085 and high-avoidant attachment had higher mean binge frequency than those with high genetic risk but low-avoidant attachment (β = –7.96; t = –2.07; P = 0.042). Conclusions FTO genotypes associated with risk for obesity and loss of control of eating, specifically rs1421085, may interact with insecure attachment in a way that may exacerbate binge eating among women with BED.

Obesity in youth increases the risk of type 2 diabetes (T2D), and both are risk factors for neurocognitive deficits. Exercise attenuates the risk of obesity and T2D while improving cognitive function. In adults, these benefits are associated with the actions of the brain-derived neurotrophic factor (BDNF), a protein critical in modulating neuroplasticity, glucose regulation, fat oxidation, and appetite regulation in adults. However, little research exists in youth. This study examined the associations between changes in diabetes risk factors and changes in BDNF levels after 6 months of exercise training in adolescents with obesity. The sample consisted of 202 postpubertal adolescents with obesity (70% females) aged 14–18 years who were randomized to 6 months of aerobic and/or resistance training or nonexercise control. All participants received a healthy eating plan designed to induce a 250/kcal deficit per day. Resting serum BDNF levels and diabetes risk factors, such as fasting glucose, insulin, homeostasis model assessment (HOMA-B—beta cell insulin secretory capacity) and (HOMA-IS—insulin sensitivity), and hemoglobin A1c (HbA1c), were measured after an overnight fast at baseline and 6 months. There were no significant intergroup differences on changes in BDNF or diabetes risk factors. In the exercise group, increases in BDNF were associated with reductions in fasting glucose (β = −6.57, SE = 3.37, p=0.05) and increases in HOMA-B (β = 0.093, SE = 0.03, p=0.004) after controlling for confounders. No associations were found between changes in diabetes risk factors and BDNF in controls. In conclusion, exercise-induced reductions in some diabetes risk factors were associated with increases in BDNF in adolescents with obesity, suggesting that exercise training may be an effective strategy to promote metabolic health and increases in BDNF, a protein favoring neuroplasticity. This trial is registered with ClinicalTrials.gov NCT00195858, September 12, 2005 (funded by the Canadian Institutes of Health Research).

Background: Childhood is a critical period for brain development, and the behaviours that comprise a typical 24-hour day contribute to cognitive performance in children. This study investigated the relationship between cognition and meeting the 24-hour movement behaviour guidelines of ≥60 minutes of physical activity, ≤2 hours of recreational screen time, and 9-11 hours of sleep per day in 9-10 year olds. Methods: This study presents cross-sectional data from the first annual curated release of the Adolescent Brain Cognitive Development Study (ABCD) - a 10-year longitudinal, observational study investigating brain development in American children. Data were collected from 21 study sites across the United States between September 2016 and 2017. Participants were 4,524 American children aged 9-10 years. Exposures were physical activity, recreational screen time, and sleep duration. The primary outcome was global cognition and secondary outcomes were crystallized and fluid intelligence. Findings: The mean (SD) number of guideline recommendations met was 1·1 (0·9). Overall, 50·9% of participants met the sleep recommendation, 36·5% met screen time, and 17·5% met the physical activity recommendation. 65·3% of participants met at least 1, whereas 4·7% of participants met all 3 recommendations. Multi-level regression analysis revealed a significant positive gradient between global cognition and each additional recommendation met [β=1·48 (95% CI: 0·86, 2·11), p

Background: Evidence suggests that fat-free mass and resting metabolic rate (RMR), but not fat mass, are strong predictors of energy intake (EI). However, body composition and RMR do not explain the entire variance in EI, suggesting that other factors may contribute to this variance.Objective: We aimed to investigate the associations between body mass index (in kg/m2), fat mass, fat-free mass, and RMR with acute (1 meal) and daily (24-h) EI and between fasting appetite ratings and certain eating behavior traits with daily EI. We also evaluated whether RMR is a predictor of the error variance in acute and daily EI.Design: Data collected during the control condition of 7 studies conducted in Ottawa, Ontario, Canada, were included in these analyses (n = 191 and 55 for acute and daily EI, respectively). These data include RMR (indirect calorimetry), body composition (dual-energy X-ray absorptiometry), fasting appetite ratings (visual analog scales), eating behavior traits (Three-Factor Eating Questionnaire), and EI (food buffet or menu).Results: Fat-free mass was the best predictor of acute EI (R2 = 0.46; P < 0.0001). The combination of fasting prospective food consumption ratings and RMR was the best predictor of daily EI (R2 = 0.44; P < 0.0001). RMR was a statistically significant positive predictor of the error variance for acute (R2 = 0.20; P < 0.0001) and daily (R2 = 0.23; P < 0.0001) EI. RMR did, however, remain a statistically significant predictor of acute (R2 = 0.32; P < 0.0001) and daily (R2 = 0.30; P < 0.0001) EI after controlling for this error variance.Conclusions: Our findings suggest that combined measurements of appetite ratings and RMR could be used to estimate EI in weight-stable individuals. However, greater error variance in acute and daily EI with increasing RMR values was observed. Future studies are needed to identify whether greater fluctuations in daily EI over time occur with increasing RMR values. This trial was registered at clinicaltrials.gov as NCT02653378.

Increases in energy, lipid and carbohydrate intakes during the luteal phase have been previously observed. However, it is not known whether this is due to phase-dependent variations in the reward value of certain foods. Moreover, increases in olfactory sensitivity have been proposed and may be involved in these changes in food reward. Therefore, we examined olfactory performance and the reward value of foods varying in fat content and taste. Seventeen women (Body mass index: 22.3 ± 1.6 kg/m2; Body fat-DXA: 28.5 ± 6.8%) were recruited to participate in 3 identical sessions, performed during distinct phases of the menstrual cycle – early follicular/menstruation, late follicular/ovulation and mid-luteal – verified by plasma sex-steroid hormones and oral temperature. Food preference, implicit wanting, and explicit wanting and liking for visual food cues, varying in fat content and taste, were measured with a validated experimental platform involving a forced choice computer task. Odour threshold, odour discrimination, odour identification and total odour scores were measured using odourized pens. Ad libitum energy and macronutrient intake was measured with a validated food menu. Results showed greater total odour scores (p < 0.05), explicit wanting for high fat foods (p < 0.05) and lipid intake (p < 0.05) during the mid-luteal phase. Inter-correlations between these variables were non-significant. These findings support previous observations of increased lipid intake during the luteal phase and provide evidence for phase-dependent variation in overall olfactory performance and explicit wanting for high fat foods.

Adolescents spend up to 6–8 h/day in sedentary screen behaviour and screen time is an independent risk factor for obesity. However, the mechanisms by which screen time confers obesity risk remain unclear. Via community level recruitment this study examined whether the relationship between screen time behaviours and body mass index (BMI: kg/m2) was mediated by total energy intake or macronutrient consumption. In a cross-sectional study of post-pubertal adolescents (N = 283: 86M, 197F) with overweight or obesity at baseline of an intervention for weight control, we examined self-reported total energy intake (mean Calories from 3 day food diary), macronutrient intake (grams/day of carbohydrate, fat, protein) and total screen time (aggregate of hours/day watching TV, playing seated video games, and recreational computer use). BMI was objectively measured and converted to standardized scores (z-BMI). Simple and multiple mediation analyses were conducted using the bootstrapping approach described by Preacher and Hayes. Covariates included age, sex, ethnicity, parental education, Tanner stage, and self-reported physical activity. The relationship between screen time and z-BMI was significantly mediated by energy intake. Higher levels of carbohydrate intake, but not fat or protein intake, significantly mediated the relationship between screen time and z-BMI (95% bias-corrected and accelerated confidence interval [0.0004, 0.0074]). Higher carbohydrate intake mediated the relationship between TV viewing and z-BMI, and video gaming and z-BMI. In conclusion, the relationship between screen time and BMI appears to be mediated by increased energy intake, primarily in the form of higher carbohydrate intake. It is possible that reducing time spent watching TV and playing video games may reduce food intake and help promote dietary adherence needed for weight management in obese adolescents. Clinical Trial Registration ClinicalTrials.gov ID: NCT00195858 .

The present study examined gender differences in response to methylphenidate (MPH) on energy intake and macronutrient preference. Twelve adults (6 men, 6 women) were given placebo or short-acting MPH (0.5 mg/kg) in a randomized, double blind, placebo-controlled crossover fashion. One hour after drug administration, appetite sensations and the relative reinforcing value of energy-dense snack food were measured, followed immediately by energy intake and macronutrient preference during a buffet lunch. Relative to placebo, men exhibited a significantly greater reduction in energy intake, fat intake, and carbohydrate intake after MPH administration compared with women. Future research is needed to verify these initial findings.

Introduction This study evaluated whether intervening with child care providers would increase physical activity (PA) and reduce adiposity in preschoolers. Methods This was a two-arm, parallel group, cluster RCT whereby six child care centers were randomly assigned in equal numbers to intervention ( n =40 children) or control ( n =43 children). Participants were aged 3–5 years and attended licensed child care centers. Child care providers received two 3-hour train-the-trainer workshops and a training manual at program initiation aimed at increasing structured and unstructured PA through active play. Control child care centers implemented their standard curriculum. PA and sedentary behavior were measured by accelerometry, and body composition was measured using bioelectrical impedance at baseline and 6 months. Data were collected in 2011–2012 and analyzed in April 2015. Results Linear mixed-effects modeling showed that at 6 months, children in the intervention group demonstrated greater increases in minutes per preschool day spent in overall PA (22.5 minutes, 95% CI=8.9, 36.1, p =0.002), and light-intensity PA (16.1 minutes, 95% CI=5.2, 26.7, p =0.004), but changes between groups in moderate to vigorous PA did not differ. The intervention group showed greater reductions in body fat percentage (−1.9%, 95% CI=−3.5, −0.3, p =0.023) and fat mass (−0.3 kg, 95% CI=−0.7, −0.1, p =0.018), but groups did not differ on fat-free mass, BMI, or z-BMI. Conclusions Provider-led intervention in child care centers increased preschoolers' PA and reduced adiposity, therefore may represent a viable approach to promoting PA and related health benefits in preschool-aged children. Trial Registration This study is registered at www.clinicaltrials.gov NCT02293278.

Background: Millions of Americans attempt to lose weight each year, and it is unclear whether the modality of acute, tightly controlled energy depletions can differently affect appetite parameters and olfaction. Objective: The objectives were to examine how the modality of an acute 3-d isocaloric 25% energy depletion by dieting alone or by aerobic exercise alone differently affects appetite and appetite-related hormones, ad libitum feeding, food reward (snack points), and olfaction. Design: Ten male participants with a mean ± SD age of 23.7 ± 5.1 y and an initial mean ± SD body weight of 83.2 ± 11.5 kg participated in this randomized crossover design. Baseline measurement [day 1 of the control condition (CON1)] was performed and repeated 3 d later [day 4 of the control condition (CON4)], after which randomization was applied to the order of the 2 experimental conditions: 25% daily needs energy deficits induced by diet only (DIET) and by exercise only (EX) and tested before [day 1 of DIET (DIET1) and day 1 of EX (EX1)] and after 3 d [day 4 of DIET (DIET4) and day 4 of EX (EX4)] of the intervention. Body weight, leptin and ghrelin concentrations, relative-reinforcing value of food, and olfaction were measured at days 1 and 4. Body composition (dual-energy X-ray absorptiometry), ad libitum energy intake (EI; buffet), and palatability (visual analog scale) were measured only at day 4. Results: Relative to CON4, EI (P = 0.001), palatability (P = 0.01), and odor threshold (P = 0.05) were higher at DIET4; relative to CON4, palatability (P = 0.03) was higher at EX4. Compared with EX4, EI was higher for DIET4 (P = 0.006). Relative to CON4, snack points earned were higher at DIET4 (P = 0.03) and EX4 (P = 0.001); more snack points were earned at EX4 relative to DIET4 (P = 0.001). Conclusions: Compared with the control condition, DIET represented a greater acute challenge to appetite regulation than EX, as demonstrated by greater appetite and ad libitum EI. This study confirms that compared with depletions by exercise alone, acute caloric restriction results in rapid changes in appetite that result in compensatory eating, which may initially dissuade potential success in weight-loss efforts. This trial was registered at clinicaltrials.gov as NCT02653378.

Aim Excessive screen time and diminished health-related quality of life (HRQoL) are greater problems for obese than nonobese adolescents, but no research has examined the relationship between these two variables. This study examined the association between screen time and HRQoL in overweight and obese adolescents. Methods A sample of 358 overweight and obese adolescents aged 14–18 years were assessed at baseline between 2005 and 2010 as part of the Canadian Healthy Eating, Aerobic and Resistance Training in Youth (HEARTY) trial. We used the Pediatric Quality of Life (PEDS-QL) and other self-report measures to assess HRQoL and screen time, defined as how long the 261 females and 97 males spent viewing TV, using the computer and playing video games. Results After adjusting for socio-demographic variables, adiposity, physical activity and diet, screen time duration was associated with reduced overall HRQoL (adjusted r = −0.16, s = −0.16, p = 0.009) and psychosocial HRQoL (adjusted r = −0.16, s = −0.18, p = 0.004), but not physical HRQoL. No differences were found between males and females. Conclusion Screen time was associated with reduced overall and psychosocial HRQoL in overweight and obese adolescents. Future research should determine whether reducing screen time improves overall and psychosocial HRQoL in obese adolescents.

Introduction We examined the impact of a 24 hour complete fast (vs. fed state) on two measures of food reward: 1) ‘wanting’, as measured by response to food images and by the relative-reinforcing value of food (RRV), and 2) ‘liking’, as measured by response to food images and the hedonic evaluation of foods consumed. Methods Utilizing a randomized crossover design, 15 subjects (9 male; 6 female) aged 28.6±4.5 yrs with body mass index 25.3±1.4 kg/m2 were randomized and counterbalanced to normal feeding (FED) and 24-hour fast (FASTED) conditions. Trait characteristics were measured with the Three Factor Eating Questionnaire. Two computer tasks measured food reward: 1) RRV progressive ratio task, 2) explicit ‘liking’ and ‘wanting’ (Leeds Food Preference Questionnaire, LFPQ). Also measured were ad libitum energy intake (EI; buffet) and food ‘liking’ (visual analogue scale) of personalized stimuli. Results There were no significant anthropometric changes between conditions. Appetite scores, hedonic ratings of ‘liking’, and ad libitum EI all significantly increased under the FASTED condition (p

Introduction: Polymorphisms of the dopamine receptor D2 (DRD2) gene have been associated with obesity phenotypes. Our aim was to examine if the genotype of TaqIA Restriction Fragment Length Polymorphism (RFPL) was related to an attenuated weight loss response or to changes in energy expenditure (EE) and food preference before and after weight loss. Methods: Obese post-menopausal women (age = 57.1 ± 4.6 yr, weight = 85.4 ± 15.4 kg and BMI = 32.8 ± 4.5 kg/m2) were genotyped for TaqIA (n = 127) by using PCR–RFLP analysis and categorized as possessing at least one copy of the A1 allele (A1+) or no copy (A1−). Women were randomized into two groups, caloric restriction (CR) and caloric restriction + resistance training (CRRT) and in this study were further classified as follows: A1+CR, A1+CRRT, A1-−CR and −A1−CRRT. Body composition, total daily EE, physical activity EE, Resting EE (REE), and energy intake were obtained at baseline and post-intervention using DXA, doubly-labeled water, indirect calorimetry, and 3-day dietary records, respectively. Results: Overall, all of the anthropometric variables and REE significantly decreased post-intervention (p < 0.001). Women in the CRRT group lost significantly more fat mass (FM) than the CR women (p < 0.05). There were significant time by group by allele interactions for attenuated body weight (BW), BMI, and FM loss for A1+ (vs. A1−) in CRRT (p < 0.05) and for increased % carbohydrate intake (p < 0.01). Conclusion: TaqIA genotype was associated with body weight loss post-intervention; more specifically, carriers of the A1 allele lost significantly less BW and FM than the A1− and had increased carbohydrate intake in the CRRT group.

Changes in smell function can modify feeding behaviour but there is little evidence of how acute negative energy balance may impact olfaction and palatability. In a within-subjects repeated measures design, 15 subjects (nine male; six female) aged 28.6±4.5 years with initial body weight (BW) 74.7±4.9 kg and body mass index (BMI) 25.3±1.4 kg/m(2) were randomized and tested at baseline (FED) and Post Deprivation (FASTED) for nasal chemosensory performance (Sniffin' Sticks) and food palatability (visual analogue scale). Significant main effects for time indicated improvements in the FASTED session for odor threshold, odor discrimination, and total odor scores (TDI), and for increased palatability. There were significant positive correlations between initial BW and the change in odor threshold (r=.52) and TDI scores (r=.53). Positive correlations were also noted between delta identification score and delta palatability (r=.68). When the sample was split by sex, only for females were there significant correlations between delta palatability and: delta BW (r=.88); delta odor identification (r=.94); and delta TDI score (r=.85). Fasting for 24h improved smell function and this was related to increased palatability ratings and initial BW. Further studies should confirm the role of BW and sex in the context of olfaction, energy deprivation and palatability.

In a detailed analysis of the psychobiology of feeding behavior with particular attention to food reward, this chapter describes theories and data on reinforcement and taste perception. This chapter will also provide evidence for an explanation of what may account for the large variation in the individual response to a similar food stimulus, highlighting the role of peripheral feeding signals (e.g., the “hunger hormone” ghrelin or the adiposity-marker hormone leptin) and the role of the neurotransmitter dopamine. What is interesting is that when energy deprivation is prolonged not only does palatable food become more salient but items that would normally not be selected can also become attractive. The fact that this increased hedonic valence is similar for rodents and primates (including humans) is indicative of common (neuro)biological underpinnings. Although it will be argued that nutritional state – whether defined by acute or chronic energy deprivation – can impact the “liking” and “wanting” of a food stimulus, it will also be argued that humans also eat in the absence of energy needs due to simple Pavlovian learning. New evidence from studies on taste and olfaction are presented and it appears that, continuous with leptin’s role as a marker of energy reserves, when leptin levels are high (signaling adequate reserves) there is a corresponding decrease in sensitivity to taste and to olfactory stimuli. Merging together literature on the dopamine hypothesis of feeding and the incentive salience hypothesis, this chapter will also describe the current views of how the neurotransmitter dopamine impacts the motivational component of food reward. The pleasure/palatability component of food reward will also be described in a comprehensive format at the behavioral and neurophysiological level. A question that remains to be answered is the extent to which homeostatic components (nutritional need-states) can impact the quality of orosensory reward, thereby enhancing food hedonics and ultimately compromising appetite control.

There have been reports of an inverse relationship between meal frequency (MF) and adiposity. It has been postulated that this may be explained by favourable effects of increased MF on appetite control and possibly on gut peptides as well. The main goal of the present study was to investigate whether using a high MF could lead to a greater weight loss than that obtained with a low MF under conditions of similar energy restriction. Subjects were randomised into two treatment arms (high MF = 3 meals+3 snacks/d or low MF = 3 meals/d) and subjected to the same dietary energy restriction of − 2931 kJ/d for 8 weeks. Sixteen obese adults (n 8 women and 8 men; age 34·6 (sd 9·5); BMI 37·1 (sd 4·5) kg/m2) completed the study. Overall, there was a 4·7 % decrease in body weight (P sd 2·9) kg; P sd 3·1) kg; P sd 0·8) kg/m2; P

s / Can J Diabetes 39 (2015) S17eS18 S18

s / Can J Diabetes 39 (2015) S38eS74 S64 Methods: Fifty-eight participants who were either normal weight (NW) or overweight/obese (OW), and either attempting or not attempting weight loss (WL), exercised at a moderate and vigorous intensity for 25 minutes. Subsequently, they estimated how many calories they expended, and the amount of food equivalent to the calories expended. Results: The OW-noWL group (150 166 kcal) significantly overestimated vigorous exercise expenditure compared to the NW-WL group (-46 166 kcal) and OW-WL group (-10 180 kcal) (P 0.05). Between exercise conditions, only the OW-noWL group significantly overestimated energy expenditure during vigorous exercise to a great extent (125 83 kcal) compared to moderate exercise (P

Background: Evidence suggests that fat-free mass and resting metabolic rate (RMR), but not fat mass, are strong predictors of energy intake (EI). However, body composition and RMR do not explain the entire variance in EI, suggesting that other factors may contribute to this variance.Objective: We aimed to investigate the associations between body mass index (in kg/m2), fat mass, fat-free mass, and RMR with acute (1 meal) and daily (24-h) EI and between fasting appetite ratings and certain eating behavior traits with daily EI. We also evaluated whether RMR is a predictor of the error variance in acute and daily EI.Design: Data collected during the control condition of 7 studies conducted in Ottawa, Ontario, Canada, were included in these analyses (n = 191 and 55 for acute and daily EI, respectively). These data include RMR (indirect calorimetry), body composition (dual-energy X-ray absorptiometry), fasting appetite ratings (visual analog scales), eating behavior traits (Three-Factor Eating Questionnaire), and EI (food buffet or menu).Results: Fat-free mass was the best predictor of acute EI (R2 = 0.46; P < 0.0001). The combination of fasting prospective food consumption ratings and RMR was the best predictor of daily EI (R2 = 0.44; P < 0.0001). RMR was a statistically significant positive predictor of the error variance for acute (R2 = 0.20; P < 0.0001) and daily (R2 = 0.23; P < 0.0001) EI. RMR did, however, remain a statistically significant predictor of acute (R2 = 0.32; P < 0.0001) and daily (R2 = 0.30; P < 0.0001) EI after controlling for this error variance.Conclusions: Our findings suggest that combined measurements of appetite ratings and RMR could be used to estimate EI in weight-stable individuals. However, greater error variance in acute and daily EI with increasing RMR values was observed. Future studies are needed to identify whether greater fluctuations in daily EI over time occur with increasing RMR values. This trial was registered at clinicaltrials.gov as NCT02653378.

Gary S Goldfield,1–5 Lauren Marie Dowler,5 Mark Walker,6,7 Jameason D Cameron,3 Zachary M Ferraro,1 Eric Doucet,3 Kristi B Adamo1–31Healthy Active Living and Obesity Research Group, Children's Hospital of Eastern Ontario Research Institute, 2Department of Paediatrics, 3School of Human Kinetics, 4School of Psychology, University of Ottawa, 5Department of Psychology, Carleton University, 6Ottawa Hospital Research Institute, 7Department of Obstetrics and Gynecology, University of Ottawa, Ottawa, ON, CanadaBackground: Excessive gestational weight gain is associated with postpartum weight retention and downstream child obesity. Dopamine plays a critical role in the regulation of energy intake and body weight. The purpose of this study was to examine the relationship between excessive gestational weight gain and dopamine pathway-related polymorphisms, namely the variable nucleotide tandem repeat in the 3´untranslated region (UTR) region of the SLC6A3 (DAT-1) dopamine transporter gene and the 30-base pair variable nucleotide tandem repeat polymorphism of the 5´UTR of the monoamine oxidase-A (MAO-A) gene.Methods: Ninety-three women of mean age 31.7 ± 4.2 years were recruited from the Ottawa and Kingston birth cohort and assessed at 12–20 weeks’ gestation. Mean body mass index was 22.7 ± 2.5 kg/m2. Excessive gestational weight gain was defined according to the 2009 Institute of Medicine guidelines based on body mass index. Genotype analyses were performed using polymerase chain reaction and agarose gel electrophoresis.Results: There was no relationship between the prevalence or magnitude of excessive gestational weight gain among women with the 3´ UTR single nucleotide polymorphism of the DAT-1 gene. However, 70% (19 of 27) of women carrying the MAO-A 4/4 (high activity) allele exceeded recommendations for gestational weight gain compared with 48% (32 of 60) of those with the pooled 3/3, 3/4, and 3/3.5 (low activity) alleles (P < 0.05). Similarly, those with the MAO-A 4/4 allele had significantly greater gestational weight gain than those with the 3/3, 3/4, or 3/3.5 pooled genotypes (19.3 ± 4.1 versus 17.0 ± 5.0 kg, P = 0.03).Conclusion: Carriers of the 4/4 variants of the MAO-A gene may be at increased risk for excessive gestational weight gain.Keywords: gestational weight gain, dopamine genes, monoamine oxidase-A