The Effects of Exercise on Food Intake and Body Fatness: A Summary of Published Studies

A Structural Equation Modelling Approach to Examine the Mediating Effect of Stress on Diet in Culturally Diverse Women of Childbearing Age

Background: Stress has been shown to be associated with poor nutrition among young women. However, studies around the topic have major limitations in their methodologies and the role of confounding factors within this association remains unclear in the literature. Objective: To investigate the associations between stress and dietary quality/patterns in a culturally diverse population of childbearing-aged women. Methods: A secondary analysis of data from two studies conducted in UK and Lebanon was performed using Structural Equation Modelling (SEM) to explore the role of country context, socio-economic status, and physical variables. Participants were healthy women of childbearing age (n = 493). Variables measured were dietary intake, stress, physical activity, sociodemographic variables, and Body Mass Index. These were included in the SEM analysis to examine the mediating effect of stress. Results: The results showed that, among all variables, only country had a significant effect on dietary quality and patterns through the mediatory effect of stress. Participants from Lebanon were found to have higher stress levels compared to participants from the UK, and this contributed to a lower adherence to a Mediterranean diet. Conclusions: This study shows that for women of childbearing age, having a good diet quality/pattern is dependent on stress levels and country context.

Voluntary wheel running access produces opposite effects in male and female rats on both palatable diet consumption and associated ventral striatal opioid- and dopamine-related gene expression

The relationship between physical activity levels and feeding behaviors has been a focus of preclinical research for decades, yet this interaction has only recently been explored for potential sex differences. The aim of the present study was to isolate sex-dependent effects of voluntary wheel running (RUN) vs. sedentary locked wheel (SED) home cage conditions on palatability-driven feeding behavior using a 2-diet choice task between standard chow and a high-fat diet. The sex-dependent effects of physical activity on feeding behavior were examined following a within-subject novel reversal design of physical activity conditions (i.e., RUN > SED > RUN), to assess temporal sensitivity of the interaction. Following the final 2 weeks of reestablished and sustained RUN vs. SED conditions in separate groups of both males and females, reward-related opioid and dopamine gene expression within the nucleus accumbens (Acb) brain region were analyzed. Results demonstrated that the initial RUN > SED transition led to sex-dependent effects of SED condition, as males increased, and females decreased their high fat consumption, compared to their respective high fat consumption during previous RUN condition phase. Following reintroduction to the RUN condition, males decreased, and females increased their high fat consumption, compared to their separate SED control group. Last, sex-dependent shifts in ventral striatal opioid- and dopamine-related gene expression were observed to parallel the behavioral effects. The major findings of the study reveal that SED and RUN home cage conditions shift palatability-driven feeding in the opposite direction for males and females, these effects are sensitive to reversal, and these sex-dependent feeding behaviors track sex-dependent changes to critical reward-related gene expression patterns in the Acb. Considering the present high rates of sedentary behavior and obesity, furthering our understanding of the interaction between physical activity (or lack thereof) and feeding behavior should be a priority, especially in the context of these divergent sex-dependent outcomes.

The complex pattern of the effects of prolonged frequent exercise on appetite control, and implications for obesity

From a public health perspective, much of the interest in the relationship between exercise and appetite rests on the implications for energy balance and obesity. Energy balance reflects a dynamic 2-way interaction between energy expenditure (EE) and energy intake (EI). Physical activity and exercise, and appetite are the behavioural components of EE and EI, respectively. Beyond EE, exercise is a powerful and complex physiological stimulus acting on several bodily systems. There are multiple effects of frequent and prolonged exercise on appetite which include inter alia an increase in fasting hunger, an enhancement of post-prandial satiety, a modulation of the hedonic responses to food and improvements in eating behaviour traits. These lead to variable adjustments in EI and in a reduction in the susceptibility to overconsumption. Frequent and prolonged physical activity and exercise behaviour can strengthen and sensitise the appetite control system, whilst physical inactivity and sedentariness (low level of EE) fails to downregulate EI and can permit overconsumption. Not all of the effects of exercise operate uniformly to drive appetite in the same direction. The complexity of the interaction between EE and EI means that the effects of prolonged exercise are characterised by substantial individual heterogeneity. This leads to variable effects on energy balance and body mass.

Long-term aerobic and combined exercises enhance the satiety response and modulate the energy intake in patients with type 2 diabetes mellitus (T2DM): A randomized controlled trial

BACKGROUND

Energy homeostasis plays a vital role in achieving glycemic control in people with type 2 diabetes mellitus (T2DM). Exercise is known to increase energy expenditure. However, its role in energy intake has not been explored in people with T2DM. Thus, this study aimed at determining the impact of long-term aerobic and combined exercises in modulating hunger, satiety and energy intake in T2DM.

METHODS

A randomized controlled trial, with 108 people with T2DM, aged 35-60 years were assigned into an aerobic, combined (aerobic and resistance) and a control group. Primary outcomes were subjective levels of hunger and satiety measured by a 100 mm visual analogue scale in relation to a standard breakfast meal (453 kcal) and energy and macronutrient intake determined by a 3-day diet diary at 0, 3 and 6 months.

RESULTS

Aerobic and combined groups exhibited reduced hunger and increased satiety at 3 and 6 months (p < 0.05). The combined group demonstrated a profound increase in satiety at 3 and 6 months compared to aerobics (3 months; p = 0.008, 6 months; p = 0.002) and controls (3 months; p = 0.006, 6 months, p = 0.014). Mean daily energy intake was reduced only at 6 months in the aerobic group (p = 0.012), whereas it was reduced in the combined group at 3 and at 6 months compared to controls (3 months: p = 0.026, 6 months: p = 0.022).

CONCLUSIONS

Long-term aerobic and combined exercises produced a reduction in hunger, energy intake and increase satiety in people with T2DM. Despite energy expenditure, exercise seems to play a significant role in reducing energy intake as well. Combined exercises show more advantages over aerobic exercise since combined exercises have a greater impact on satiety and energy intake in people with T2DM.

TRIAL REGISTRATION NUMBER

SLCTR/2015/029, https://slctr.lk/trials/slctr-2015-029 .

Are Physical Activity and Sedentary Screen Time Levels Associated With Food Consumption in European Adolescents? The HELENA Study

One of the current main public health problems is the prevalence of obesity in children. Unhealthy lifestyle behaviors such as poor dietary habits, high sedentary screen time (SST), and low levels of physical activity (PA) have a strong tendency to track from childhood into adulthood. The aim of this manuscript is to assess the association between meeting or not meeting the PA and SST recommendations and the consumption of different food groups.

Data were obtained from a sample of European adolescents from the multicenter cross-sectional HELENA study. In all, 1448 adolescents from 8 cities were included. PA was objectively measured by accelerometry and dietary intake by 24-hour dietary records. Adolescents were grouped according to PA and SST recommendations.

In both sexes, intake of savory snacks was higher in those groups who did not meet any of the recommendations (p < 0.05). For males, those who met both recommendations were more likely to drink/eat milk, yogurt, and water (p < 0.05). Those not meeting recommendations were more likely to drink sugar-sweetened beverages (p < 0.05). For females, those not meeting recommendations were less likely to eat fruits and vegetables and more likely to have a higher intake of fats and oils (p < 0.05).

Those adolescents meeting PA and SST recommendations had a higher intake of healthy foods, like fruit and vegetables and dairy products. However, the negative relationship unhealthier food and SST is stronger in males independently of PA. More studies assessing the combined effect of both PA and SST regarding dietary habits in children and adolescents are needed.

Sex Differences Across the Life Course: A Focus On Unique Nutritional and Health Considerations among Women

In the United States, women, while having a longer life expectancy than men, experience a differential risk for chronic diseases and have unique nutritional needs based on physiological and hormonal changes across the life span. However, much of what is known about health is based on research conducted in men. Additional complexity in assessing nutritional needs within gender include the variations in genetics, body compositions, hormonal milieus, underlying chronic diseases, and medication usage, with this list expanding as we consider these variables across the life course. It is clear women experience nutrient shortfalls during key periods of their lives, which may differentially impact their health. Consequently, as we move into the era of precision nutrition, understanding these sex- and gender-based differences may help optimize recommendations and interventions chosen to support health and weight management. Recently, a scientific conference was convened with content experts to explore these topics from a life-course perspective at biological, physiological, and behavioral levels. This publication summarizes the presentations and discussions from the workshop and provides an overview of important nutrition and related lifestyle considerations across the life course. The landscape of addressing female-specific nutritional needs continues to grow; now more than ever, it is essential to increase our understanding of the physiological differences between men and women, and determine how these physiological considerations may aid in optimizing nutritional strategies to support certain personal goals related to health, quality of life, sleep, and exercise performance among women.

Longitudinal patterns of lifestyle behaviours in adolescence: a latent transition analysis

The interdependence among eating behaviour (EB), physical activity (PA) and sedentary time (ST) suggests simultaneously identifying homogeneous profiles and describing their changes. This study aimed to (1) identify cross-sectional lifestyle behaviour profiles and their 2-year changes among French school-age adolescents and (2) identify factors associated with these profiles and changes. Longitudinal data from adolescents who participated in the PRomotion de l'ALIMentation et de l'Activité Physique trial were used. PA and ST were assessed with the International Physical Activity Questionnaire and EB with a FFQ. Profiles at baseline and their changes were identified by latent transition analysis. Multinomial logistic regression models were used to identify factors associated with profiles and their changes. Among 2390 adolescents included (14-18 years), five baseline profiles that differed mainly in EB were identified: 'healthy diet and high PA (7·9 %)', 'big eater and moderate to high PA (23·8 %)', 'healthy diet and low PA (31·2 %)', 'restrictive diet and moderate PA (20·6 %)' and 'sugar products, nibbling and moderate PA (16·5 %)'. Young adolescents, those who were overweight or obese and socially advantaged, were more in the 'healthy diet and low PA' than others. Boys, older and socially less advantaged adolescents exhibited more 'unfavourable' than 'mixed' changes, while adolescents with overweight or obesity had less 'unfavourable' than 'mixed' changes. In conclusion, adolescents were twice the number in the least than the most favourable profile. Findings highlighted the importance of EB among adolescents and suggest taking adolescents' sociodemographic and weight characteristics into account in interventions aimed at acting on adolescents' behaviours.

Physical activity and sleep quality correlations with anthropometric measurements in young adults

OBJECTIVE

This cross-sectional study examined correlations between physical activity and anthropometrics as well as sleep quality and anthropometrics.

PARTICIPANTS

College students (n = 85) with average age 25.6 ± 5.4 years.

METHODS

Participants received full-body dual-energy x-ray absorptiometry scans and completed validated surveys: Habitual Physical Activity questionnaire, Pittsburgh Sleep Quality Index (PSQI), and Epworth Sleepiness Scale.

RESULTS

Males reported more sports-related physical activity than females (p = 0.041). Physical activity indices and percent body fat were inversely correlated (total ⍴ = -0.320, p < 0.001; sport β = -0.378, p = 0.003). Participants had poor overall sleep quality (PSQI = 6.19 ± 2.99). The PSQI sleep quality index: disturbance was directly correlated with body mass index (BMI) (β = 0.328, p = 0.007).

CONCLUSION

Health interventions on college campuses should promote more physical activity and better quality sleep as these factors were related to improved body anthropometrics and potentially reduced chronic disease risk.

Adiposity Mediates the Association of Objectively Measured Physical Activity with Cardiorespiratory Fitness in Children

Background: The relationship of physical activity (PA) to cardiorespiratory fitness (CRF) is well established in children. However, the extent to which adiposity affects this association remains unclear. Objective: The study aimed to explore whether the relationships of different PA intensities to CRF are explained by adiposity. Methods: Cross-sectional data were collected from 374 children (51.87% boys) aged 7-12 years. The time spent (min/day) in vigorous PA (VPA), moderate PA (MPA), light PA (LPA), and sedentary behavior was objectively measured using triaxial accelerometry. Height, weight, and waist circumference (WC) were objectively measured, from which the BMI was derived. The 20-meter shuttle run test was conducted to estimate maximal oxygen consumption [VO_2max, mL/(kg·min)]. Linear mixed models and mediation analysis with bootstrapping were used to analyze data. Results: VO_2max was positively associated with VPA [β = 0.143, 95% confidence interval (95% CI): 0.091 to 0.194], MPA (β = 0.051, 95% CI: 0.016 to 0.086), and moderate-to-vigorous PA (MVPA) (β = 0.052, 95% CI: 0.029 to 0.075), but not LPA or sedentary time. Both BMI and WC partially mediated the relationships of VPA and MVPA to VO_2max, with the percentage of the total effect mediated by adiposity ranging from 18.0% to 19.6%. Similar results were also observed among boys but not among girls. Conclusions: Only moderate or vigorous intensity of PA is favorably correlated with CRF in children. BMI and WC play a pivotal mediating role in these associations, especially in boys, suggesting that promoting higher intensity of PA might benefit children's CRF through reducing adiposity.

Development of a scale to measure reasons for eating less healthily after exercise: the compensatory unhealthy eating scale

OBJECTIVE

Patterns of 'compensatory eating' following exercise are likely to be harmful for long-term health and counterproductive for weight loss goals. However, little is known about reasons why people eat unhealthily after exercising. Thus, we aimed to develop a measure that assesses reasons why people engage in compensatory unhealthy eating.

METHOD

A multi-stage approach using exploratory and confirmatory factor analysis was used to develop and replicate a scale and validate its psychometric properties in three different samples. Participants (total N = 814) rated their agreement with statements capturing different reasons for eating less healthily after exercise.

RESULTS

Factor analysis revealed four distinct factors underlying compensatory eating: Reward for Effort, Permission to Consume, Need to Consume, and Reduced Self-Control. The resulting Compensatory Unhealthy Eating Scale (CUES) had good internal consistency and convergent validity.

CONCLUSION

The CUES has utility as a tool to assess compensatory eating behaviour. Further research should examine who is most likely to compensate and under what circumstances. Broadening current knowledge of compensatory eating after exercise may facilitate development of strategies to improve health behaviour regulation.

The Effects of the Type of Exercise and Physical Activity on Eating Behavior and Body Composition in Overweight and Obese Subjects

The aim of this study was to examine whether a type of exercise favors better compliance with a prescribed diet, higher eating-related motivation, healthier diet composition or greater changes in body composition in overweight and obese subjects. One hundred and sixty-two (males n = 79), aged 18-50 years, were randomized into four intervention groups during 24 weeks: strength, endurance, combined strength + endurance and guideline-based physical activity; all in combination with a 25-30% caloric restriction diet. A food frequency questionnaire and a "3-day food and drink record" were applied pre- and post-intervention. Diet and exercise-related motivation levels were evaluated with a questionnaire developed for this study. Body composition was assessed by DXA and habitual physical activity was measured by accelerometry. Body weight, body mass index (BMI) and body fat percentage decreased and lean body mass increased after the intervention, without differences by groups. No interactions were observed between intervention groups and time; all showing a decreased in energy intake (p < 0.001). Carbohydrate and protein intakes increased, and fat intake decreased from pre- to post-intervention without significant interactions with intervention groups, BMI category or gender (p < 0.001). Diet-related motivation showed a tendency to increase from pre- to post-intervention (70.0 ± 0.5 vs 71.0 ± 0.6, p = 0.053), without significant interactions with intervention groups, BMI or gender. Regarding motivation for exercise, gender x time interactions were observed (F(1,146) = 7.452, p = 0.007): Women increased their motivation after the intervention (pre: 17.6 ± 0.3, post: 18.2 ± 0.3), while men maintained it. These findings suggest that there are no substantial effects of exercise type on energy intake, macronutrient selection or body composition changes. After a six-month weight loss program, individuals did not reduce their motivation related to diet or exercise, especially women. Individuals who initiate a long-term exercise program do not increase their energy intake in a compensatory fashion, if diet advices are included.

ASSOCIATION BETWEEN PHYSICAL ACTIVITY PRACTICE AND CLUSTERING OF HEALTH RISK BEHAVIORS IN ADOLESCENTS

Objective:

To verify the association between participation in physical activity (PA) and the clustering of health risk behaviors (HRB) in adolescents of both genders.

Methods:

A cross-sectional study involving 862 adolescents (11 to 17 years old) enrolled in 14 randomly selected public schools from Curitiba, Paraná, Brazil. Participation in PA, screen time, consumption of fruit, vegetables, cigarettes and alcoholic beverages were the criteria evaluated. Multinomial logistic regression tested the association between participation in PA and clustering of HRB, and results are expressed Odds Ratio (OR) with 95% confidence intervals (95%CI).

Results:

Adolescents with high participation in PA had lower odds of clustering 2-3 HRB (OR 0.38, 95%CI 0.21-0.68; p<0.01) and 4-5 HRB (OR 0.29; 95%IC 0.16-0.53; p<0.01). Boys with high participation in PA had lower chances of clustering 2-3 HRB (OR 0.31, 95%CI 0.13-0.75; p=0.01), and girls had lower odds of clustering 2-3 HRB (OR 0.41; 95%CI 0.17-0.99; p=0.04) and 4-5 HRB (OR 0.25; 95%CI 0.10-0.61; p<0.01).

Conclusions:

High participation in PA was inversely associated with the clustering of HRB in adolescents.

The influence of 15-week exercise training on dietary patterns among young adults

BACKGROUND/OBJECTIVES

Little is currently known about how exercise may influence dietary patterns and/or food preferences. The present study aimed to examine the effect of a 15-week exercise training program on overall dietary patterns among young adults.

SUBJECTS/METHODS

This study consisted of 2680 young adults drawn from the Training Intervention and Genetics of Exercise Response (TIGER) study. Subjects underwent 15 weeks of aerobic exercise training, and exercise duration, intensity, and dose were recorded for each session using computerized heart rate monitors. In total, 4355 dietary observations with 102 food items were collected using a self-administered food frequency questionnaire before and after exercise training (n = 2476 at baseline; n = 1859 at 15 weeks). Dietary patterns were identified using a Bayesian sparse latent factor model. Changes in dietary pattern preferences were evaluated based on the pre/post-training differences in dietary pattern scores, accounting for the effects of gender, race/ethnicity, and BMI.

RESULTS

Within each of the seven dietary patterns identified, most dietary pattern scores were decreased following exercise training, consistent with increased voluntary regulation of food intake. A longer duration of exercise was associated with decreased preferences for the western (β: -0.0793; 95% credible interval: -0.1568, -0.0017) and snacking (β: -0.1280; 95% credible interval: -0.1877, -0.0637) patterns, while a higher intensity of exercise was linked to an increased preference for the prudent pattern (β: 0.0623; 95% credible interval: 0.0159, 0.1111). Consequently, a higher dose of exercise was related to a decreased preference for the snacking pattern (β: -0.0023; 95% credible interval: -0.0042, -0.0004) and an increased preference for the prudent pattern (β: 0.0029; 95% credible interval: 0.0009, 0.0048).

CONCLUSIONS

The 15-week exercise training appeared to motivate young adults to pursue healthier dietary preferences and to regulate their food intake.

Comparison of energy-matched high-intensity interval and moderate-intensity continuous exercise sessions on latency to eat, energy intake, and appetite

High-intensity interval exercises (HIIex) have gained popularity but their effects on eating behavior are poorly known. The aim of this study was to evaluate whether the effects of HIIex on the 3 main components of eating behavior (appetite, intake, and latency to eat) differ from those of moderate-intensity continuous exercises (MICex) for the same energy expenditure. Fifteen young normal-weight males completed 3 sessions in a counterbalanced order: HIIex (30-s bouts at 90% of maximal oxygen uptake interceded with 60-s bouts at 35% of maximal oxygen uptake for 20 min), MICex (42% of maximal oxygen uptake for 40 min), and a resting session (REST). Trials were scheduled 80 and 100 min after a standard breakfast for MICex and HIIex, respectively. At 120 min, participants were isolated until they asked for lunch. Appetite was rated on 4 visual analog scales (hunger, desire to eat, fullness, and prospective consumption) every 15 min until meal request. Results showed that the mean latency of requesting lunch was significantly longer after HIIex than after REST (+17.3 ± 4.3 min, P = 0.004), but not after MICex (P = 0.686). Energy intake was not different between conditions, leading to a negative energy balance in the 2 exercise sessions. Thus, the effects of HIIex on eating behavior are likely primarily mediated through the latency of meal initiation. However, inter-individual variability was large and further studies are needed to identify the predictive factors of this response.

Associations between Physical Activity and Food Intake among Children and Adolescents: Results of KiGGS Wave 2

A balanced diet and sufficient physical activity are essential for the healthy growth of children and adolescents and for obesity prevention. Data from the second wave of the population-based German Health Interview and Examination Survey for Children and Adolescents (KiGGS Wave 2; 2014-2017) were used to analyse the association between food intake and physical activity among 6- to 17-year-old children and adolescents (n = 9842). Physical exercise (PE) and recommended daily physical activity (RDPA) were assessed with self-administered questionnaires and food intake by a semi-quantitative food frequency questionnaire. Multivariable logistic regression was used to analyse the association between food group intake (dependent variable) and level of PE or RDPA. High levels of physical activity (PE or RDPA) were associated with higher consumption of juice, water, milk, dairy products, fruits, and vegetables among both boys and girls, and among boys with a higher intake of bread, potatoes/pasta/rice, meat, and cereals. Higher PE levels were also less likely to be associated with a high soft drink intake. High levels of RDPA were associated with high intake of energy-dense foods among boys, which was not observed for PE. This study indicates that school-aged children and adolescents with higher levels of physical activity consume more beneficial foods and beverages compared to those with lower physical activity levels.

Physiology of energy homeostasis: Models, actors, challenges and the glucoadipostatic loop

The aim of this review is to discuss the physiology of energy homeostasis (EH), which is a debated concept. Thus, we will see that the set-point theory is highly challenged and that other models integrating an anticipative component, such as energy allostasis, seem more relevant to experimental reports and life preservation. Moreover, the current obesity epidemic suggests that EH is poorly efficient in the modern human dietary environment. Non-homeostatic phenomena linked to hedonism and reward seem to profoundly impair EH. In this review, the apparent failed homeostatic responses to energy challenges such as exercise, cafeteria diet, overfeeding and diet-induced weight loss, as well as their putative determinants, are analyzed to highlight the mechanisms of EH. Then, the hormonal, neuronal, and metabolic factors of energy intake or energy expenditure are briefly presented. Last, this review focuses on the contributions of two of the most pivotal and often overlooked determinants of EH: the availability of endogenous energy and the pattern of energy intake. A glucoadipostatic loop model is finally proposed to link energy stored in adipose tissue to EH through changes in eating behavior via leptin and sympathetic nervous system activity.

Sweet and Umami Taste Perception Differs with Habitual Exercise in Males

Taste is influenced by several factors. However, whether habitual exercise level is associated with differences in taste perception has received little investigation. The aim of this study was to determine if habitual exercise is associated with differences in taste perception in men. Active (n = 16) and inactive (n = 14) males, between ages 18⁻55, underwent two days of sensory testing, using prototypical taste stimuli of high and low concentrations for sweet, salt, bitter, sour, umami, and carbohydrate (maltodextrin). Mean perceived intensity and hedonic ratings were recorded. Eating behaviour was assessed by the three factor eating questionnaire and food intake by EPIC food frequency questionnaire (FFQ). There were moderate to large differences between the two groups in perceived intensity for sweet taste at the high concentration and umami taste at both high and low concentrations, with active males recording a higher perceived intensity (p < 0.05 for all). The active group also recorded a greater dislike for umami low and carbohydrate low concentration (p < 0.01). Salt, bitter and sour perception did not significantly differ between the two groups. FFQ analysis showed no difference in % energy from macronutrients between the groups. Eating behaviour traits correlated with sweet taste intensity and umami taste liking, independent of activity status. Results indicated that sweet and umami taste perception differ in active compared to inactive males. Habitual exercise level should be considered in taste perception research and in product development. Whether differences in taste perception could be one factor influencing food intake and thus energy balance with habitual exercise warrants further investigation.

The effects of scheduled running wheel access on binge-like eating behavior and its consequences

Binge eating disorder (BED) is an eating disorder involving repeated, intermittent over consumption of food in brief periods of time, usually with no compensatory behaviors. There are few successful treatments and the underlying neural mechanisms remain unclear. In the current study, we hypothesized that voluntary running wheel (RW) activity could reduce binge-like eating behavior in a rat model. Rats were given intermittent (3 times/wk) limited (1hr) access to a high-fat food (Crisco), in addition to continuously available chow. Crisco was available every Mon, Wed, and Fri for 1hr before dark onset. Rats were divided into 2 groups: those with RW access during the first half of the experiment and sedentary during the second half (RW-SED) and those that were sedentary during the first half of the experiment and had RW access during the second half (SED-RW). Crisco intake was significantly less in both groups during the period of time with a RW present. Within the bingeing RW-SED rats, the gene expression of the orexigenic neuropeptides AgRP and NPY were similar to a non-bingeing sedentary control (CON) group, while the expression of the anorexigenic neuropeptide POMC was significantly increased relative to the SED-RW and CON groups. Despite elevated POMC, the rats continued to binge. Additionally, within both groups, the gene expression of the D2R and Oprm1 in the NAc and the VTA were altered suggesting that the reward system was stimulated by both the bingeing behavior and the running wheel activity. Overall, access to a RW and the resulting activity significantly reduced binge-like behavior as well as modulated the effects of binging on brain appetite and reward systems.

Influence of Hot and Cold Environments on the Regulation of Energy Balance Following a Single Exercise Session: A Mini-Review

Understanding the regulation of human food intake in response to an acute exercise session is of importance for interventions with athletes and soldiers, as well as overweight individuals. However, the influence of hot and cold environments on this crucial function for the regulation of body mass and motor performance has not been summarized. The purpose of this review was to exhaustively search the literature on the effect of ambient temperature during an exercise session on the subsequent subjective feeling of appetite, energy intake (EI) and its regulation. In the absence of stress due to environmental temperature, exercise-induced energy expenditure is not compensated by EI during an ad libitum meal following the session, probably due to decreased acylated ghrelin and increased peptide tyrosine tyrosine (PYY), glucagon-like peptide 1 (GLP-1), and pancreatic polypeptide (PP) levels. No systematic analysis has been yet made for major alterations of relative EI in cold and hot environments. However, observed eating behaviors are altered (proportion of solid/liquid food, carbohydrate/fat) and physiological regulation appears also to be altered. Anorexigenic signals, particularly PYY, appear to further increase in hot environments than in those that are thermoneutral. Ghrelin and leptin may be involved in the observed increase in EI after exercise in the cold, in parallel with increased energy expenditure. The potential influence of ambient thermal environment on eating behaviors after an exercise session should not be neglected.

The Effect of a 20 km Run on Appetite Regulation in Long Distance Runners

The purpose of the present study was to investigate appetite-related hormonal responses and energy intake after a 20 km run in trained long distance runners. Twenty-three male long-distance runners completed two trials: either an exercise trial consisting of a 20 km outdoor run (EX) or a control trial with an identical period of rest (CON). Blood samples were collected to determine plasma acylated ghrelin, peptide YY_3-36 (PYY_3-36) and other hormonal and metabolite concentrations. Energy intake during a buffet test meal was also measured 30 min after the exercise or rest periods. Although plasma acylated ghrelin concentrations were significantly decreased after the 20 km run (p < 0.05), plasma PYY_3-36 did not change significantly following exercise. Absolute energy intake during the buffet test meal in EX (1325 ± 55 kcal) was significantly lower than that in CON (1529 ± 55 kcal), and there was a relatively large degree of individual variability for exercise-induced changes in energy intake (−40.2% to 12.8%). However, exercise-induced changes in energy intake were not associated with plasma acylated ghrelin or PYY_3-36 responses. The results demonstrated that a 20 km run significantly decreased plasma acylated ghrelin concentrations and absolute energy intake among well-trained long distance runners.

Food group preferences and energy balance in moderately obese postmenopausal women subjected to brisk walking program

The objective of the study was to examine the effects of a 16-week walking program on food group preferences and energy balance of sedentary, moderately obese (body mass index, 29-35 kg/m(2)), postmenopausal Caucasian women, aged 60 ± 5 years old. One hundred and fifty-six volunteers were subjected to 3 sessions/week of 45 min of walking at 60% of heart rate reserve. Total energy intake (TEI) and food group preferences (3-day dietary record), total energy expenditure (TEE, 3-day physical activity diary), cardiorespiratory fitness (2-km walking test), anthropometry, and body composition (bioelectrical impedance) were measured before and after walking. Data were statistically analyzed using an ANOVA with repeated measures on 1 factor (time). The modest increase in TEE of 151 ± 24 kcal/day (p < 0.0001) leads to body weight, fat mass losses, and waist girth reduction (p < 0.0001). TEI remained unchanged despite a slight decrease in carbohydrate intake and a minor increase in protein intake (p < 0.05). Analysis of food records revealed a decreased consumption of fruits (p < 0.05) and sweet and fatty foods (p < 0.01), but an increase in oil consumption (p < 0.0001) after walking. Women with the highest body weight loss showed the greatest reduction in the consumption of fruits, sugar, sweet foods, and fatty foods (p < 0.05). Women with the greatest fat mass loss showed the highest decrease in fatty food intake (p < 0.05). In conclusion, although our walking program changed some food group consumption patterns, body weight loss was primarily because of the increased TEE.

Acute aerobic exercise increases implicit approach motivation for dessert images

We examined the effect of acute exercise compared to a cognitive task on implicit approach/avoidance motivation to dessert food images using the Dessert–Approach–Avoidance Task. Participants randomized to exercise had a greater increase in approach motivation to dessert images compared to those completing cognitive tasks ( p=0.046), adjusting for disordered eating, task difficulty, and changes in negative affect. This study provides the first evidence for the use of the Dessert–Approach–Avoidance Task to evaluate the effects of acute exercise on implicit motivations for dessert images. Future studies should examine implicit response to food images using the Dessert–Approach–Avoidance Task in response to chronic exercise.

Low Dopamine D2 Receptor Increases Vulnerability to Obesity Via Reduced Physical Activity, Not Increased Appetitive Motivation

BACKGROUND

The dopamine D2 receptor (D2R) has received much attention in obesity studies. Data indicate that D2R is reduced in obesity and that the TaqA1 D2R variant may be more prevalent among obese persons. It is often suggested that reduced D2R generates a reward deficiency and altered appetitive motivation that induces compulsive eating and contributes to obesity. Although dopamine is known to regulate physical activity, it is often neglected in these studies, leaving open the question of whether reduced D2R contributes to obesity through alterations in energy expenditure and activity.

METHODS

We generated a D2R knockdown (KD) mouse line and assessed both energy expenditure and appetitive motivation under conditions of diet-induced obesity.

RESULTS

The KD mice did not gain more weight or show increased appetitive motivation compared with wild-type mice in a standard environment; however, in an enriched environment with voluntary exercise opportunities, KD mice exhibited dramatically lower activity and became more obese than wild-type mice, obtaining no protective benefit from exercise opportunities.

CONCLUSIONS

These data suggest the primary contribution of altered D2R signaling to obesity lies in altered energy expenditure rather than the induction of compulsive overeating.

Alterations in energy balance from an exercise intervention with ad libitum food intake

Better understanding is needed regarding the effects of exercise alone, without any imposed dietary regimens, as a single tool for body-weight regulation. Thus, we evaluated the effects of an 8-week increase in activity energy expenditure (AEE) on ad libitum energy intake (EI), body mass and composition in healthy participants with baseline physical activity levels (PAL) in line with international recommendations. Forty-six male adults (BMI = 19·7–29·3 kg/m²) participated in an intervention group, and ten (BMI = 21·0–28·4 kg/m²) in a control group. Anthropometric measures, cardiorespiratory fitness, EI, AEE and exercise intensity were recorded at baseline and during the 1st, 5th and 8th intervention weeks, and movement was recorded throughout. Body composition was measured at the beginning and at the end of the study, and resting energy expenditure was measured after the study. The intervention group increased PAL from 1·74 (se 0·03) to 1·93 (se 0·03) (P < 0·0001) and cardiorespiratory fitness from 41·4 (se 0·9) to 45·7 (se 1·1) ml O₂/kg per min (P = 0·001) while decreasing body mass (−1·36 (se 0·2) kg; P = 0·001) through adipose tissue mass loss (ATM) (−1·61 (se 0·2) kg; P = 0·0001) compared with baseline. The control group did not show any significant changes in activity, body mass or ATM. EI was unchanged in both groups. The results indicate that in normal-weight and overweight men, increasing PAL from 1·7 to 1·9 while keeping EI ad libitum over an 8-week period produces a prolonged negative energy balance. Replication using a longer period (and/or more intense increase in PAL) is needed to investigate if and at what body composition the increase in AEE is met by an equivalent increase in EI.

Personality and Situation Predictors of Consistent Eating Patterns

INTRODUCTION

A consistent eating style might be beneficial to avoid overeating in a food-rich environment. Eating consistency entails maintaining a similar dietary pattern across different eating situations. This construct is relatively under-studied, but the available evidence suggests that eating consistency supports successful weight maintenance and decreases risk for metabolic syndrome and cardiovascular disease. Yet, personality and situation predictors of consistency have not been studied.

METHODS

A community-based sample of 164 women completed various personality tests, and 139 of them also reported their eating behaviour 6 times/day over 10 observational days. We focused on observations with meals (breakfast, lunch, or dinner). The participants indicated if their momentary eating patterns were consistent with their own baseline eating patterns in terms of healthiness or size of the meal. Further, participants described various characteristics of each eating situation.

RESULTS

Eating consistency was positively predicted by trait self-control. Eating consistency was undermined by eating in the evening, eating with others, eating away from home, having consumed alcohol and having undertaken physical exercise. Interactions emerged between personality traits and situations, including punishment sensitivity, restraint, physical activity and alcohol consumption.

CONCLUSION

Trait self-control and several eating situation variables were related to eating consistency. These findings provide a starting point for targeting interventions to improve consistency, suggesting that a focus on self-control skills, together with addressing contextual factors such as social situations and time of day, may be most promising. This work is a first step to provide people with the tools they need to maintain a consistently healthy lifestyle in a food-rich environment.

Associations of Physical Activity and Sedentary Behaviors with Dietary Behaviors among US High School Students

BACKGROUND

Physical activity (PA), sedentary behaviors, and dietary behaviors are each associated with overweight and obesity among youth. However, the associations of PA and sedentary behaviors with dietary behaviors are complex and not well understood.

PURPOSE

To describe the associations of PA and sedentary behaviors with dietary behaviors among a representative sample of US high school students.

METHODS

We analyzed data from the 2010 National Youth Physical Activity and Nutrition Study (NYPANS). Using logistic regression models which controlled for sex, race/ethnicity, grade, body weight status, and weight management goals, we compared dietary behaviors among students who did and did not meet national recommendations for PA and sedentary behaviors.

RESULTS

Students who participated in recommended levels of daily PA (DPA) and muscle strengthening PA (MSPA) were more likely than those who did not to eat fruits and vegetables. Students who exceeded recommended limits for television (TV) and computer/video game (C/VG) screen time were less likely than those who did not to consume fruits and vegetables and were more likely to consume fast food and sugar-sweetened beverages.

CONCLUSIONS

Researchers may want to address PA, sedentary behaviors, and dietary behaviors jointly when developing health promotion and obesity prevention programs for youth.

Wheel running reduces high-fat diet intake, preference and mu-opioid agonist stimulated intake

The ranges of mechanisms by which exercise affects energy balance remain unclear. One potential mechanism may be that exercise reduces intake and preference for highly palatable, energy dense fatty foods. The current study used a rodent wheel running model to determine whether and how physical activity affects HF diet intake/preference and reward signaling. Experiment 1 examined whether wheel running affected the ability of intracerebroventricular (ICV) μ opioid receptor agonist D-Ala2, NMe-Phe4, Glyol5-enkephalin (DAMGO) to increase HF diet intake. Experiment 2 examined the effects of wheel running on the intake of and preference for a previously preferred HF diet. We also assessed the effects of wheel running and diet choice on mesolimbic dopaminergic and opioidergic gene expression. Experiment 1 revealed that wheel running decreased the ability of ICV DAMGO administration to stimulate HF diet intake. Experiment 2 showed that wheel running suppressed weight gain and reduced intake and preference for a previously preferred HF diet. Furthermore, the mesolimbic gene expression profile of wheel running rats was different from that of their sedentary paired-fed controls but similar to that of sedentary rats with large HF diet consumption. These data suggest that alterations in preference for palatable, energy dense foods play a role in the effects of exercise on energy homeostasis. The gene expression results also suggest that the hedonic effects of exercise may substitute for food reward to limit food intake and suppress weight gain.

Appetite control and energy balance: impact of exercise

Exercise is widely regarded as one of the most valuable components of behaviour that can influence body weight and therefore help in the prevention and management of obesity. Indeed, long-term controlled trials show a clear dose-related effect of exercise on body weight. However, there is a suspicion, particularly fuelled by media reports, that exercise serves to increase hunger and drive up food intake thereby nullifying the energy expended through activity. Not everyone performing regular exercise will lose weight and several investigations have demonstrated a huge individual variability in the response to exercise regimes. What accounts for this heterogeneous response? First, exercise (or physical activity) through the expenditure of energy will influence the energy balance equation with the potential to generate an energy deficit. However, energy expenditure also influences the control of appetite (i.e. the physiological and psychological regulatory processes underpinning feeding) and energy intake. This dynamic interaction means that the prediction of a resultant shift in energy balance, and therefore weight change, will be complicated. In changing energy intake, exercise will impact on the biological mechanisms controlling appetite. It is becoming recognized that the major influences on the expression of appetite arise from fat-free mass and fat mass, resting metabolic rate, gastric adjustment to ingested food, changes in episodic peptides including insulin, ghrelin, cholecystokinin, glucagon-like peptide-1 and tyrosine-tyrosine, as well as tonic peptides such as leptin. Moreover, there is evidence that exercise will influence all of these components that, in turn, will influence the drive to eat through the modulation of hunger (a conscious sensation reflecting a mental urge to eat) and adjustments in postprandial satiety via an interaction with food composition. The specific actions of exercise on each physiological component will vary in strength from person to person (according to individual physiological characteristics) and with the intensity and duration of exercise. Therefore, individual responses to exercise will be highly variable and difficult to predict.

Resistance to exercise-induced weight loss: compensatory behavioral adaptations

In many interventions that are based on an exercise program intended to induce weight loss, the mean weight loss observed is modest and sometimes far less than what the individual expected. The individual responses are also widely variable, with some individuals losing a substantial amount of weight, others maintaining weight, and a few actually gaining weight. The media have focused on the subpopulation that loses little weight, contributing to a public perception that exercise has limited utility to cause weight loss. The purpose of the symposium was to present recent, novel data that help explain how compensatory behaviors contribute to a wide discrepancy in exercise-induced weight loss. The presentations provide evidence that some individuals adopt compensatory behaviors, that is, increased energy intake and/or reduced activity, that offset the exercise energy expenditure and limit weight loss. The challenge for both scientists and clinicians is to develop effective tools to identify which individuals are susceptible to such behaviors and to develop strategies to minimize their effect.

Implementation of permutation testing to determine clustering of social and behavioral risk factors for coronary heart disease, National Health and Nutrition Examination Survey 2001-2004

PURPOSE

To determine whether social and behavioral risk factors for coronary heart disease, including education, physical activity, fruit/vegetable intake, and smoking, cluster (i.e., co-occur more than expected as the result of chance) in U.S. adults.

METHODS

The study included 4305 male and 4673 female subjects aged ≥20 years from the National Health and Nutrition Examination Survey. Risk factors included: ≤high school diploma/general educational development certificate; <150 minutes of moderate/vigorous physical activity per week; <3 or <2 servings of vegetables and fruit, respectively, per day; and smoking cigarettes. Indicator variables were summed into a sociobehavioral risk index (SRI, range 0 [no risk factors] to 4 [all risk factors]). Ratios of observed-to-expected prevalence (under the assumption of independence) of the SRI were assessed. Statistical significance was evaluated by the use of randomly permuted average observed-to-expected SRI ratios and 95% confidence intervals (95% CIs).

RESULTS

In male subjects, the ratio of observed-to-expected prevalence of SRI = 0 was 1.70 (permuted ratio = 1.00; 95% CI: 0.92-1.08), and SRI = 4 was 2.10 (permuted ratio = 1.00, 95% CI: 0.86-1.14), demonstrating significant clustering. In females, the ratio of observed-to-expected prevalence of SRI = 0 was 1.67 (permuted ratio = 1.00, 95% CI: 0.92-1.08), and SRI = 4 was 1.86 (permuted ratio = 1.00, 95% CI: 0.85-1.15).

CONCLUSIONS

Social and behavioral risk factors for coronary heart disease cluster in this sample of U.S. adults.

Energy compensation after an aerobic exercise session in high-fat/low-fit and low-fat/high-fit young male subjects

There is general agreement that exercise-induced energy expenditure is not entirely compensated for at the next meal or over the following 24 h, but inter-individual variability is high. The role of ‘fatness and fitness’ in this variability has never been assessed. Therefore, eighteen non-obese male subjects aged 22·2 (sd2·0) years were selected and separated into a ‘high-fatness and low-fitness’ (Hfat/Lfit,n9) and a ‘low-fatness and high-fitness’ (Lfat/Hfit,n9) group, according to three criteria: maximal oxygen uptake; weekly hours of physical activity; fat mass index. At 1 h before lunch, they were subjected to 60 min of exercise on a cycle ergometer (70 % VO2max), or stayed at rest. Then, they self-reported food intake in diaries until the next breakfast. Intake at lunch was not different between conditions, but was higher after exercise than after rest over the 24 h, leading to a significant but partial mean level of compensation of 49·8 (sem16·5) and 37·8 (sem24·6) % for the Hfat/Lfit and Lfat/Hfit groups, respectively. Energy compensation at lunch and over the 24 h were strongly correlated (r0·76,P< 0·001). Both groups consumed more fat and protein after exercise than after rest over the 24 h, but the percentage of energy derived from fat increased only in the Hfat/Lfit group (2·1 (sem0·6) %,P= 0·026). Thus, the energy cost of an aerobic exercise session was partially compensated over the next 24 h independently of the ‘fatness and fitness’ status, but ‘high-fat and low-fit’ individuals compensated more specifically on fats.

The Interaction Between Exercise, Appetite, and Food Intake

Exercise could indirectly affect body weight by exerting changes on various components of appetite control, including nutrient and taste preferences, meal size and frequency, and the drive to eat. This review summarizes the evidence on how exercise affects appetite and eating behavior and in particular answers the question, “Does exercise induce an increase in food intake to compensate for the increase in energy expenditure?” Evidence will be presented to demonstrate that there is no automatic increase in food intake in response to acute exercise and that the response to repeated exercise is variable. The review will also identify areas of further study required to explain the variability. One limitation with studies that assess the efficacy of exercise as a method of weight control is that only mean data are presented—the individual variability tends to be overlooked. Recent evidence highlights the importance of characterizing the individual variability by demonstrating exercise-induced changes in appetite. Individuals who experience lower than theoretically predicted reductions in body weight can be characterized by hedonic (eg, pleasure) and homeostatic (eg, hunger) features.

Putting desire on a budget: dopamine and energy expenditure, reconciling reward and resources

Accumulating evidence indicates integration of dopamine function with metabolic signals, highlighting a potential role for dopamine in energy balance, frequently construed as modulating reward in response to homeostatic state. Though its precise role remains controversial, the reward perspective of dopamine has dominated investigation of motivational disorders, including obesity. In the hypothesis outlined here, we suggest instead that the primary role of dopamine in behavior is to modulate activity to adapt behavioral energy expenditure to the prevailing environmental energy conditions, with the role of dopamine in reward and motivated behaviors derived from its primary role in energy balance. Dopamine has long been known to modulate activity, exemplified by psychostimulants that act via dopamine. More recently, there has been nascent investigation into the role of dopamine in modulating voluntary activity, with some investigators suggesting that dopamine may serve as a final common pathway that couples energy sensing to regulated voluntary energy expenditure. We suggest that interposed between input from both the internal and external world, dopamine modulates behavioral energy expenditure along two axes: a conserve-expend axis that regulates generalized activity and an explore-exploit axes that regulates the degree to which reward value biases the distribution of activity. In this view, increased dopamine does not promote consumption of tasty food. Instead increased dopamine promotes energy expenditure and exploration while decreased dopamine favors energy conservation and exploitation. This hypothesis provides a mechanistic interpretation to an apparent paradox: the well-established role of dopamine in food seeking and the findings that low dopaminergic functions are associated with obesity. Our hypothesis provides an alternative perspective on the role of dopamine in obesity and reinterprets the "reward deficiency hypothesis" as a perceived energy deficit. We propose that dopamine, by facilitating energy expenditure, should be protective against obesity. We suggest the apparent failure of this protective mechanism in Western societies with high prevalence of obesity arises as a consequence of sedentary lifestyles that thwart energy expenditure.

Exercise promotes positive impression formation towards both men and women

Exercise is endorsed for its physiological and psychological benefits, and has been proposed to have positive effects on impression formation. To test this proposal, 62 female and 44 male college students read one of three brief descriptions of either a fictitious male or female "target" student. The descriptions varied only in exercise level: no exercise; moderate exercise and intensive exercise. Participants then rated the fictitious student on 38 personality traits. Ratings of characteristics that are associated with exercise (e.g. athletic; energetic) increased, while ratings associated with the lack of exercise (e.g. lazy; weak) decreased as a function of the reported level of exercise. Exercise level also positively influenced ratings of characteristics not related to exercise. These data show that even minimal information about exercise is an important component of first impressions in both men and women.

European adolescents' level of perceived stress is inversely related to their diet quality: the Healthy Lifestyle in Europe by Nutrition in Adolescence study

As stress is hypothesised to influence dietary behaviour, the relationship between perceived stress and diet quality in European adolescents was investigated. Within the Healthy Lifestyle in Europe by Nutrition in Adolescence study, adolescents (n 704, aged 12-17 years) from schools in five European cities (Ghent, Stockholm, Zaragoza, Athens and Vienna) completed a 2 d 24 h dietary recall assessment and an Adolescent Stress Questionnaire. Measurements and information were taken on height, weight, pubertal stage, parental education level, the level of moderate-to-vigorous physical activity (MVPA) and sleep duration. The Diet Quality Index for Adolescents (DQI-A) was calculated from the dietary data, which comprised three components reflecting dietary diversity, quality and equilibrium. Hierarchical linear models were performed to investigate the relationship between the adolescents' level of perceived stress and the DQI-A and its components, adjusting for relevant covariates (age, BMI z-score, pubertal stage and parental education). These models were additionally adjusted for MVPA or sleep duration. In both boys and girls, perceived stress was a significant independent negative predictor for their overall DQI-A. This inverse relationship was observed for all dietary components, except for dietary diversity in boys, and it was unaltered when additionally adjusted for MVPA or sleep duration. The observed inverse relationship between stress and diet quality within these European adolescents supports the hypothesis that stress influences dietary behaviour, thus emphasising the need for preventive stress-coping strategies for adolescents.

The relationship between substrate metabolism, exercise and appetite control: does glycogen availability influence the motivation to eat, energy intake or food choice?

The way in which metabolic fuels are utilized can alter the expression of behaviour in the interests of regulating energy balance and fuel availability. This is consistent with the notion that the regulation of appetite is a psychobiological process, in which physiological mediators act as drivers of behaviour. The glycogenostatic theory suggests that glycogen availability is central in eliciting negative feedback signals to restore energy homeostasis. Due to its limited storage capacity, carbohydrate availability is tightly regulated and its restoration is a high metabolic priority following depletion. It has been proposed that such depletion may act as a biological cue to stimulate compensatory energy intake in an effort to restore availability. Due to the increased energy demand, aerobic exercise may act as a biological cue to trigger compensatory eating as a result of perturbations to muscle and liver glycogen stores. However, studies manipulating glycogen availability over short-term periods (1-3 days) using exercise, diet or both have often produced equivocal findings. There is limited but growing evidence to suggest that carbohydrate balance is involved in the short-term regulation of food intake, with a negative carbohydrate balance having been shown to predict greater ad libitum feeding. Furthermore, a negative carbohydrate balance has been shown to be predictive of weight gain. However, further research is needed to support these findings as the current research in this area is limited. In addition, the specific neural or hormonal signal through which carbohydrate availability could regulate energy intake is at present unknown. Identification of this signal or pathway is imperative if a casual relationship is to be established. Without this, the possibility remains that the associations found between carbohydrate balance and food intake are incidental.

Clustering patterns of physical activity, sedentary and dietary behavior among European adolescents: The HELENA study

Background

Evidence suggests possible synergetic effects of multiple lifestyle behaviors on health risks like obesity and other health outcomes. A better insight in the clustering of those behaviors, could help to identify groups who are at risk in developing chronic diseases. This study examines the prevalence and clustering of physical activity, sedentary and dietary patterns among European adolescents and investigates if the identified clusters could be characterized by socio-demographic factors.

Methods

The study comprised a total of 2084 adolescents (45.6% male), from eight European cities participating in the HELENA (Healthy Lifestyle in Europe by Nutrition in Adolescence) study. Physical activity and sedentary behavior were measured using self-reported questionnaires and diet quality was assessed based on dietary recall. Based on the results of those three indices, cluster analyses were performed. To identify gender differences and associations with socio-demographic variables, chi-square tests were executed.

Results

Five stable and meaningful clusters were found. Only 18% of the adolescents showed healthy and 21% unhealthy scores on all three included indices. Males were highly presented in the cluster with high levels of moderate to vigorous physical activity (MVPA) and low quality diets. The clusters with low levels of MVPA and high quality diets comprised more female adolescents. Adolescents with low educated parents had diets of lower quality and spent more time in sedentary activities. In addition, the clusters with high levels of MVPA comprised more adolescents of the younger age category.

Conclusion

In order to develop effective primary prevention strategies, it would be important to consider multiple health indices when identifying high risk groups.

Relationship between self-reported dietary intake and physical activity levels among adolescents: the HELENA study

BACKGROUND

Evidence suggests possible synergetic effects of multiple lifestyle behaviors on health risks like obesity and other health outcomes. Therefore it is important to investigate associations between dietary and physical activity behavior, the two most important lifestyle behaviors influencing our energy balance and body composition. The objective of the present study is to describe the relationship between energy, nutrient and food intake and the physical activity level among a large group of European adolescents.

METHODS

The study comprised a total of 2176 adolescents (46.2% male) from ten European cities participating in the HELENA (Healthy Lifestyle in Europe by Nutrition in Adolescence) study. Dietary intake and physical activity were assessed using validated 24-h dietary recalls and self-reported questionnaires respectively. Analyses of covariance (ANCOVA) were used to compare the energy and nutrient intake and the food consumption between groups of adolescents with different physical activity levels (1st to 3rd tertile).

RESULTS

In both sexes no differences were found in energy intake between the levels of physical activity. The most active males showed a higher intake of polysaccharides, protein, water and vitamin C and a lower intake of saccharides compared to less active males. Females with the highest physical activity level consumed more polysaccharides compared to their least active peers. Male and female adolescents with the highest physical activity levels, consumed more fruit and milk products and less cheese compared to the least active adolescents. The most active males showed higher intakes of vegetables and meat, fish, eggs, meat substitutes and vegetarian products compared to the least active ones. The least active males reported the highest consumption of grain products and potatoes. Within the female group, significantly lower intakes of bread and cereal products and spreads were found for those reporting to spend most time in moderate to vigorous physical activity. The consumption of foods from the remaining food groups, did not differ between the physical activity levels in both sexes.

CONCLUSION

It can be concluded that dietary habits diverge between adolescents with different self-reported physical activity levels. For some food groups a difference in intake could be found, which were reflected in differences in some nutrient intakes. It can also be concluded that physically active adolescents are not always inclined to eat healthier diets than their less active peers.

Low fat loss response after medium-term supervised exercise in obese is associated with exercise-induced increase in food reward

Objective. To examine exercise-induced changes in the reward value of food during medium-term supervised exercise in obese individuals. Subjects/Methods. The study was a 12-week supervised exercise intervention prescribed to expend 500 kcal/day, 5 d/week. 34 sedentary obese males and females were identified as responders (R) or non-responders (NR) to the intervention according to changes in body composition relative to measured energy expended during exercise. Food reward (ratings of liking and wanting, and relative preference by forced choice pairs) for an array of food images was assessed before and after an acute exercise bout. Results. 20 responders and 14 non-responders were identified. R lost 5.2 kg ± 2.4 of total fat mass and NR lost 1.7 kg ± 1.4. After acute exercise, liking for all foods increased in NR compared to no change in R. Furthermore, NR showed an increase in wanting and relative preference for high-fat sweet foods. These differences were independent of 12-weeks regular exercise and weight loss. Conclusion. Individuals who showed an immediate post-exercise increase in liking and increased wanting and preference for high-fat sweet foods displayed a smaller reduction in fat mass with exercise. For some individuals, exercise increases the reward value of food and diminishes the impact of exercise on fat loss.

Exercise in aging: its important role in mortality, obesity and insulin resistance

The prevalence of overweight and obesity has increased dramatically over the last several decades. Obesity and physical inactivity increase the risk for cardiovascular disease, Type 2 diabetes mellitus, hypertension, dyslipidemia and certain cancers. Obesity and low levels of physical fitness are also associated with increased risk of all-cause and cardiovascular mortality. Central and total obesity, insulin resistance and inactivity increase with age. Exercise training and increased fitness promote positive changes in body composition and improve insulin sensitivity. This article will describe the effects of exercise training, both aerobic and resistive, on body composition and obesity as well as review studies investigating the effects of exercise training on glucose metabolism and insulin sensitivity in older adults. Adopting a physically active lifestyle should be emphasized in overweight and obese individuals with insulin resistance to reduce the risk for cardiovascular events in the aging population.

Influence of brisk walking on appetite, energy intake, and plasma acylated ghrelin

PURPOSE

This study examined the effect of an acute bout of brisk walking on appetite, energy intake, and the appetite-stimulating hormone-acylated ghrelin.

METHODS

Fourteen healthy young males (age 21.9 +/- 0.5 yr, body mass index 23.4 +/- 0.6 kg x m(-2), (.)VO2max 55.9 +/- 1.8 mL x kg(-1) x min(-1); mean +/- SEM) completed two 8-h trials (brisk walking and control) in a randomized counterbalanced fashion. The brisk walking trial commenced with 60 min of subjectively paced brisk walking on a level-motorized treadmill after which participants rested for 7 h. Participants rested for the duration of the control trial. Ad libitum buffet meals were offered twice during main trials (1.5-2 and 5-5.5 h). Appetite (hunger, fullness, satisfaction, and prospective food consumption) was assessed at 30-min intervals throughout. Levels of acylated ghrelin, glucose, insulin, and triacylglycerol were determined from plasma.

RESULTS

Sixty minutes of brisk walking (7.0 +/- 0.1 km x h(-1) yielded a net (exercise minus resting) energy expenditure of 2008 +/- 134 kJ, yet it did not significantly influence appetite, energy/macronutrient intake, or the plasma concentration of acylated ghrelin either during or after exercise(P > 0.05). Participants did not compensate for energy expended during walking, therefore a deficit in energy was induced (1836 kJ, 439 kcal) relative to control.

CONCLUSIONS

This study demonstrates that, despite inducing a moderate energy deficit, an acute bout of subjectively paced brisk walking does not elicit compensatory responses in acylated ghrelin, appetite, or energy intake. This finding lends support for a role of brisk walking in weight management.

Food Intake Changes Across the Menstrual Cycle in Taiwanese Women

Background: Studies in Western countries have suggested that there are relationships among sex hormones, the neuropeptide leptin, women’s food intake, and body weight changes across the menstrual cycle. However, data on this question are needed from other cultural groups. Objectives: To compare total food and macronutrient intake and serum estrogen, progesterone, and leptin levels in Taiwanese women of varying body size during three menstrual cycle phases. Method: A cross-sectional survey was conducted using a sample of 39 healthy Taiwanese women (aged 20—40 years) with regular menstrual cycles. Food journals covering 3 days, body weight, height, waist and hip circumferences, and serum samples for estrogen, progesterone, and leptin were collected at three time points during one menstrual cycle. Data were analyzed using the paired t test, mixed-model analysis, and Pearson’s correlations. Results: Regardless of body weight, women consumed more total calories (+160 kcal/day, p < .05) and more grams of protein (+6—8 g/day, p = .01) during the luteal phase and ovulation compared with the follicular phase. A higher percentage of energy was consumed as carbohydrates (CHOs) during the follicular phase (+5% of total energy intake, p < .01). No correlations were noted among serum sex hormone levels, serum leptin levels, food intake, and body weight. Discussion: The findings support the hypothesis that Taiwanese women, as previously reported in women from mixed or Western cultural groups, experience menstrual-related variations in food intake. These changes, however, were not directly linked with serum sex hormone or leptin levels.