Variation In Energy Intake Research Articles

Factors explaining seasonal variation in energy intake: a review.

Maintaining a balance between energy intake and expenditure is crucial for overall health. There are seasonal variations in energy intake, with an increase during spring and winter as well as a decrease during summer. These variations are related to a combination of environmental factors, including changes in temperature and daylight hours; social factors, including events and holidays; and physiological factors, including changes in physical activity and emotions. Accordingly, this review aimed to summarize the environmental, social, and physiological factors that contribute to seasonal variations in energy intake. A review of the current literature revealed that changes in temperature and daylight hours may affect eating behavior by altering homeostatic responses and appetite-related hormones. Additionally, increased participation in events and frequency of eating out, especially during winter vacations, may contribute to increased energy intake. Notably, these findings may not be generalisable to all populations since environmental and social factors can vary significantly depending on the local climatic zones and cultural backgrounds. The findings of the present review indicate that seasonal climate, events, and associated hormonal changes should be taken into account in order to maintain adequate energy intake throughout the year.

P14-094-23 Energy Intake Variation on Weekdays vs Weekends in Healthy, Non-Smoking Adults

P14-094-23 Energy Intake Variation on Weekdays vs Weekends in Healthy, Non-Smoking Adults

Evidence for protein leverage in a general population sample of children and adolescents

Background/ObjectivesThe strong regulation of protein intake can lead to overconsumption of total energy on diets with a low proportion of energy from protein, a process referred to as protein leverage. The protein leverage hypothesis posits that protein leverage explains variation in energy intake and potentially obesity in ecological settings. Here, we tested for protein leverage and the protein leverage hypothesis in children and adolescents.Subjects/MethodsA population sample of children, mean (SD) age 7.6 (0.4) years (n = 422), followed up at age 9.8 (0.4) years (n = 387) and at age 15.8 (0.4) years (n = 229), participating for the Physical Activity and Nutrition in Children (PANIC) study. Exposures: 4-day food records-related proportional energy intake of proteins, fats, and carbohydrates. Outcomes: energy intake, body mass index (BMI) z-score and dual-energy X-ray absorptiometry-related energy expenditure.ResultsProportional energy intake of proteins was inversely associated with energy intake following power functions at all 3 ages (mean [95%CI] strength of leverage of L = −0.36 [−0.47 to −0.25]; L = −0.26 [−0.37 to −0.15]; L = −0.25 [−0.38 to −0.13]; all P < 0.001). Mixture analysis indicated that variance in energy intake was associated primarily with the proportional intake of energy from proteins, not with either fats or carbohydrates. At all 3 ages, energy intake was not associated with BMI z-score but positively associated with energy expenditure (all P < 0.001).ConclusionsThis study provides evidence consistent with protein leverage in a population sample of children and adolescents. Increased energy intake on diets with lower protein content was counterbalanced by increased energy expenditure and therefore did not translate into increased adiposity.

Significance of autumn and winter food consumption for reproduction by Southern Beaufort Sea polar bears, Ursus maritimus

Polar bears (Ursus maritimus) in the southern Beaufort Sea experience long annual periods when preferred seal prey are scarce or are unavailable. Consumption of bowhead whale (Balaena mysticetus) carcasses from native Alaskan subsistence hunting is increasingly common for onshore polar bears, yet the energetic consequences of this consumption remain unclear. We use data on bears captured repeatedly over periods that encompassed autumn and winter, combined with calculations, to show that adult female bears likely consume an average of at least 4 seal equivalents during both autumn and winter periods and that considerable variation in energy intake exists across individual bears. We further show that subsistence-caught whale carcasses provide an upper threshold of > 4000 seal equivalents, which could potentially meet mean consumption needs of ~ 80% of the southern Beaufort Sea bear subpopulation during autumn and winter periods. Finally, we modify an existing model to show that observed mass changes over autumn and winter could substantially alter spring foraging habitat choice by females with cubs and the chance that a female with reduced energy reserves would abort a pregnancy or abandon cubs in favor of increasing her own survival; these behaviors could potentially influence population vital rates. Our study highlights the importance of mass dynamics over the autumn and winter months, points to the need for additional data on foraging and energetics over this period, and indicates that the recent declines in polar bear body condition in some subpopulations could have complex effects on reproduction.

Gestational weight gain mediates the effects of energy intake on birth weight among singleton pregnancies in the Japan Environment and Children’s Study

BackgroundExtra energy intake is commonly recommended for pregnant women to support fetal growth. However, relevant data regarding variations in energy intake and expenditure, body mass index and gestational weight gain (GWG) are frequently not considered. This study aimed to investigate how energy intake during pregnancy and gestational weight gain (GWG) are associated with birth weight.MethodsEarly pregnant women were recruited into a Japanese nationwide prospective birth cohort study between 2011 and 2014. We analysed data of 89,817 mother-child pairs of live-born non-anomalous singletons after excluding births before 28 weeks or after 42 weeks. Energy intake during pregnancy was estimated from self-administered food frequency questionnaires (FFQ) and was stratified into low, medium, and high. Participants completed the FFQ in mid-pregnancy (mean 27.9 weeks) by recalling food consumption at the beginning of pregnancy. Effects of energy intake on birth weight and mediation by GWG were estimated using the Karlson–Holm–Breen method; the method separates the impact of confounding in the comparison of conditional and unconditional parameter estimates in nonlinear probability models. Relative risks and risk differences for abnormal birth size were calculated.ResultsMean daily energy intake, GWG, and birth weight were 1682.1 (533.6) kcal, 10.3 (4.0) kg, and 3032.3 (401.4) g, respectively. 6767 and 9010 women had small-for-gestational-age and large-for-gestational-age infants, respectively. Relative to low energy intake, moderate and high intakes increased adjusted birth weights by 13 g and 24 g, respectively: 58 and 69% of these effects, respectively, were mediated by GWG. Compared with the moderate energy intake group, the low energy intake group had seven more women per 1000 women with a small-for-gestational-age birth, whereas the high energy intake group had eight more women per 1000 women with a large-for-gestational-age birth.ConclusionGWG mediates the effect of energy intake on birth weight. All pregnant women should be given adequate nutritional guidance for optimal GWG and fetal growth.

Assessing temporal eating pattern in free living humans through the myCircadianClock app.

The quality and quantity of nutrition impact health. However, chrononutrition, the timing, and variation of food intake in relation to the daily sleep-wake cycle are also important contributors to health. This has necessitated an urgent need to measure, analyze, and optimize eating patterns to improve health and manage disease. While written food journals, questionnaires, and 24-hour dietary recalls are acceptable methods to assess the quantity and quality of energy consumption, they are insufficient to capture the timing and day-to-day variation of energy intake. Smartphone applications are novel methods for information-dense real-time food and beverage tracking. Despite the availability of thousands of commercial nutrient apps, they almost always ignore eating patterns, and the raw real-time data is not available to researchers for monitoring and intervening in eating patterns. Our lab developed a smartphone app called myCircadianClock (mCC) and associated software to enable long-term real-time logging that captures temporal components of eating patterns. The mCC app runs on iOS and android operating systems and can be used to track multiple cohorts in parallel studies. The logging burden is decreased by using a timestamped photo and annotation of the food/beverage being logged. Capturing temporal data of consumption in free-living individuals over weeks/months has provided new insights into diverse eating patterns in the real world. This review discusses (1) chrononutrition and the importance of understanding eating patterns, (2) the myCircadianClock app, (3) validation of the mCC app, (4) clinical trials to assess the timing of energy intake, and (5) strengths and limitations of the mCC app.

Latest Advances in Sow Nutrition during Early Gestation.

Simple SummaryThe first month of gestation in the pig is characterised by many changes, such as entry of the embryos into the uterus, increased secretion of the pregnancy hormone, progesterone, and the implantation of the embryos into the uterus. Before implantation, embryos have not yet attached to the uterus, and are reliant on nutrients and signals in the uterine fluids, which are controlled by progesterone, among others. High feed intake has a positive effect on progesterone secretion and supports the establishment and development of pregnancy. Very low feed intakes, such as in sows competing for feed in group housing, can be detrimental to embryo survival and even the maintenance of pregnancy. After implantation, specific nutrients that improve the vascularisation of the placenta, such as arginine, can support the capacity of the uterus to support a litter of developing embryos since in this stage competition between embryos starts to play a role.In the pig, the establishment and maintenance of luteal function in early gestation is crucial to endometrial function, embryo development, and survival. The level of feed intake has a positive effect on formation of luteal tissue and progesterone secretion by the ovaries in the pre-implantation period, which is important for endometrial remodeling and secretion. These effects are independent of luteinising hormone (LH) and probably driven by metabolic cues, such as insulin and insulin-like growth factor (IGF-1), and seem to support progesterone secretion and delivery to the endometrium, the latter which occurs directly, bypassing the systemic circulation. Even after implantation, a high feed intake seems to improve embryo survival and the maintenance of pregnancy. In this stage, luteal function is LH-dependent, although normal variations in energy intake may not result in pregnancy failure, but may contribute to nutrient supply to the embryos, since in this phase uterine capacity becomes limiting. Feed incidents, however, such as unintended fasting of animals or severe competition for feed, may result in embryo or even pregnancy loss, especially in periods of seasonal infertility. Specific nutrients such as arginine have a role in the vascularisation of the placenta and can improve the uterine capacity in the period after implantation.

Triiodothyronine and cortisol levels in the face of energetic challenges from reproduction, thermoregulation and food intake in female macaques

Energy availability drives an individual's fitness and can be affected by diverse energetic challenges. The assessment of hormones involved in metabolic activity and energy mobilization provides a gateway to the study of physiological adaptations in response to changes in energy availability. Here, we investigated immunoreactive urinary total triiodothyronine (uTT3, thyroid hormone secreted through the hypothalamus-pituitary-thyroid axis and regulating the basal metabolic rate) alongside glucocorticoids (i.e. urinary cortisol, uCort, secreted through the hypothalamus-pituitary-adrenal axis and mediating energy mobilization) in wild female Assamese macaques (Macaca assamensis). Combining more than 2900; of behavioral data from 42 adult females with physiological data from 382 urine samples, we evaluated both uTT3 and uCort in relation to potential energetic challenges encountered by a female, namely fluctuations in energy intake, travel distance, reproductive state and minimum ambient temperature. As predicted, levels of both hormones changed in response to variation in energy intake with a tendency toward a positive effect on uTT3 and a significant negative effect on uCort levels. Unexpectedly, neither hormone was influenced by variation in travel distance. Reproductive state affected both hormones with higher levels of uTT3 and uCort in the second half of gestation. Finally, a decrease of minimum temperature triggered an increase in uCort but unexpectedly not in uTT3. Collectively, our results highlight the respective contribution of two endocrine axes when facing energetic challenges and the underlying metabolic strategies to cope with them. Overall, assessing thyroid hormones together with glucocorticoids provides an integrative picture in the evaluation of an individual's energy status.

Practical Application of a Bioenergetic Model to Inform Management of a Declining Fur Seal Population and Their Commercially Important Prey

Food availability is a key concern for the conservation of marine top predators, particularly during a time when they face a rapidly changing environment and continued pressure from commercial fishing activities. Northern fur seals (Callorhinus ursinus) breeding on the Pribilof Islands in the eastern Bering Sea have experienced an unexplained population decline since the late-1990s. Dietary overlap with a large U.S. fishery for walleye pollock (Gadus chalcogrammus) in combination with changes in maternal foraging behavior and pup growth has led to the hypothesis that food limitation may be contributing to the population decline. We developed age- and sex-specific bioenergetic models to estimate fur seal energy intake from May–December in six target years, which were combined with diet data to quantify prey consumption. There was considerable sex- and age-specific variation in energy intake because of differences in body size, energetic costs, and behavior; net energy intake was lowest for juveniles (18.9 MJ sea-day–1, 1,409.4 MJ season–1) and highest for adult males (66.0 MJ sea-day–1, 7,651.7 MJ season–1). Population-level prey consumption ranged from 255,232 t (222,159 – 350,755 t, 95% CI) in 2006 to 500,039 t (453,720 – 555,205 t) in 1996, with pollock comprising between 41.4 and 76.5% of this biomass. Interannual variation in size-specific pollock consumption appeared largely driven by the availability of juvenile fish, with up to 81.6% of pollock biomass coming from mature pollock in years of poor age-1 recruitment. Relationships among metabolic rates, trip durations, pup growth rates, and energy intake of lactating females suggest the most feasible mechanism to increase pup growth rates is by increasing foraging efficiency through reductions in maternal foraging effort, which is unlikely to occur without increases in localized prey density. By quantifying year-specific fur seal consumption of pollock, our study provides a pathway to incorporate fur seals into multispecies pollock stock assessment models, which is critical for fur seal and fishery management given they were a significant source of mortality for both juvenile and mature pollock.

Irregular daily energy intake and diet quality in Iranian adults.

The present cross-sectional study aimed to assess the association of daily irregularity in energy intake and diet quality among apparently healthy adults in Iran. The research was conducted on 850 adult men and women (age range: 20-59 years) who attended health care centres in Tehran. Dietary intake was assessed by three, 24-h dietary recalls. Diet quality was assessed using the Dietary Approaches to Stop Hypertension (DASH) diet score and Healthy Eating Index-2015 (HEI-2015). An irregularity score of daily energy intake was calculated based on the deviation from the 3-d mean energy intake, with a higher score indicating more fluctuations in daily energy intake. Multiple linear regression analysis was used to assess the association of irregularity score of daily energy intake with food group intakes and DASH diet score and HEI-2015, controlling for age, sex, BMI, physical activity, education level and occupation status. The range of irregularity score was 0·55-133·3 (22·4 (sd 19·0)). Higher irregularity score of daily energy intake was significantly associated with a lower consumption of fruit, vegetables, legumes, low-fat dairy products and poultry, higher consumption of soft drinks, processed meat and nuts, and lower overall DASH diet score and HEI-2015. Overall, our findings showed that more day-to-day variations in energy intake may be correlated with a lower diet quality. More research is needed to confirm the associations observed in the present study and to clarify potential mechanisms explaining these associations.

Eating Duration throughout a Rotating Shift Schedule: A Case Study

Objective The impact of the rotation between different shifts and free days within a short period of time on the food consumption is poorly addressed in the literature. Our objective was to characterize the eating duration (ED) over 10 d of clockwise rotating and to associate it with the intake of energy and macronutrients. Methods Thirty male shift-workers from a mining company were evaluated over a complete rotation shift schedule of 10 consecutive days (2 d of morning shifts, 2 d of afternoon shifts, 24 h free-day, 2 d of night shifts, and three free days). ED was defined as the interval between the first meal after awaking and last meal before sleep onset. Sleep/wake periods and food intake were evaluated by actigraphy and 24 h recalls, respectively. Generalized models were used to analyze the variation in ED and its association with nutrient intake over the shift schedule. Results ED periods showed significant variations throughout shift rotation and were associated with energy intake. The highest energy intake (3410 ± 235 kcal) and longest ED (20.7 ± 1.2 h) were found on Day 5, the day between afternoon and night shifts, and a part of Day 6 (night shift), i.e., in the longest period of wakefulness and the shortest sleep duration (4.7 ± 0.3 h) (p < 0.05 for all). The lowest energy intake (1284 ± 125 kcal) and shortest ED (4.96 ± 0.7 h) (p < 0.05) occurred after the last night shift (Day 7). The balance between the percentage of macronutrients did not differ statistically between the ED periods. Conclusions In general, longer periods of wakefulness showed greater energy intake, demonstrating the tendency of workers to eat around the clock during their shift. Even with the energy intake variation, the balance of macronutrients remained the same over the ED periods. Despite the need of confirmation in future studies, these results suggest that the management of ED period could be considered in the nutritional approach of shift workers.

Association of diurnal calorie trajectory with all-cause mortality: Findings from the National Health and Nutrition Examination Survey

The effect of diurnal variation in energy intake on mortality has not been reported. We investigated the effect of diurnal calorie trajectory on all-cause mortality using data from the National Health and Nutrition Examination Survey (NHANES). Participants in the NHANES from 1999 to 2010 were analyzed. We calculated daily energy intake and the two-hourly calorie intake according to dietary interview questionnaires, in which timing of meals, as well as energy and nutritional components of each food were recorded. The daily energy intake and the two-hourly calorie intake were divided by body weight to determine tertiles of daily energy intake and diurnal calorie trajectories, respectively. Three diurnal calorie trajectories (reference group, excess dinner, and high-calorie) were identified. The mortality data were linked to the National Death Index through the end of 2011. Cox proportional hazards models were used to compare the overall mortality among different groups. Among the 14,356 participants included in our analyses, 886 (6.2%) of them died after a median follow-up of 4.4 years. Daily energy intake tertiles were not associated with all-cause mortality in the fully adjusted model. In contrast, high-calorie trajectory was associated with a higher risk of mortality (hazard ratio 3.128, 95% CI 1.175 to 8.330, p=0.024) compared with the reference group after adjustment for relevant factors. A diurnal high-calorie trajectory was associated with a higher risk of mortality, compared with the reference group. The effect of a large evening meal on mortality merits further investigation.

Effects of predation risk on the body mass regulation of growing wood mice

AbstractBody mass in wild animals has been suggested to be regulated by the opposing fitness consequences of variation in body size (and fat storage) for starvation and predation risk. Many studies of adult mammals and birds have broadly confirmed the predictions of this model. However, relatively few studies have addressed the potential role of such trade‐offs during early phases of development when animals are growing. Similarly, studies of the impact of high‐fat diets on wild small mammals generally show a resistance to weight gain. But whether growing animals are similarly resistant is unclear. In this study, weaned wood mice (Apodemus sylvaticus) were exposed to a high risk of predation, simulated by the broadcasting of owl calls, for 66 days during which body mass and energy intake were monitored. We hypothesized that if the risk of predation plays a role in regulating body mass during this phase then animals growing under predation risk would grow less. We found female (but not male) mice exposed to the predation risk treatment had lower growth rates and ended the experiment lighter; however, variations in energy intake and resting metabolic rate did not explain the observed differences. Feeding on high‐fat diet resulted in individuals with higher body mass. Females reached their adult size earlier than males and were more responsive to the predation risk treatment when feeding on high‐fat diet. Our data suggest males body mass to have fitness consequences on social dominance and reproductive success not accounted for in the simple starvation‐predation trade‐off model.

Effects of Time Restricted Feeding on Resting Energy Expenditure and Respiratory Quotient

Time restricted feeding (TRF) is a form of dietary intake which limits the feeding time in a day. Researchers have observed weight loss and improved body composition as the original motivators for investigation of TRF. With a variation in energy intake during TRF, resting energy expenditure (REE) has been shown to increase with high caloric consumption. An increase in REE is also associated with an increase in fat free mass and physical activity. Respiratory quotient (RQ) demonstrates the ratio between CO2 production and O2 uptake, determining substrate utilization at rest. RQ has been shown to change through altered macronutrient intake. Studies indicate, a diet high in carbohydrate intake increases RQ whereas diets high in fat intake have been shown to lower RQ. RQ has also been found to decrease when subjects partake in endurance training. PURPOSE: The intent of this study was to determine the impact TRF may have on REE and RQ. METHODS: Thirty-four apparently healthy adults ages 19-51 participated in 4 weeks non-TRF and 4 weeks of TRF. The feeding window for the TRF was a nine-hour period. Participants were provided journals over the course of the study to self-record caloric intake, exercise type, and duration. REE and RQ were measured using a metabolic cart initially, after 4 weeks of non-TRF, and 4 weeks after TRF. Data was analyzed using IBM SPSS statistics. RESULTS: RQ increased significantly between pretest (0.721±0.015) and TRF testing (0.808±0.02) (p=0.01). No significance was found between non-TRF and TRF. REE had no significant difference between any of the three testing periods (p=0.233). There was no significant change in caloric intake throughout the testing (p=0.94). A significant decrease was found in total exercise days between non-TRF and TRF periods (p=0.023). CONCLUSION: This study did not find a significant change in REE during TRF. The increase in RQ may be attributed to increases in carbohydrate intake. Caloric intake was hypothesized to increase the first couple of days due to the time-restricted nature, but overall was not hypothesized to have a significant impact on energy intake or REE. Future studies should investigate the impact of TRF on macronutrient intake and carbohydrate utilization at rest.

Energy availability and nutrition during a Special Force Qualification Course (Q-Course)

IntroductionThe Special Forces (SF) are an elite military group usually engaged in physically demanding field operations, resulting among others in high daily energy requirements. Optimising energy supply and nutritional requirements...

Relationship between marine growth and sea survival of two anadromous salmonid fish species

This study found empirical evidence supporting the “growth–survival” paradigm in the marine phase of Arctic char (Salvelinus alpinus) and brown trout (Salmo trutta). The paradigm postulates that larger or faster-growing individuals are more likely to survive than smaller or slower-growing conspecifics. The study employed long-term (25 year) capture data from a trap in the River Halselva in Norway during annual migration between marine and freshwater environments. Similar results were found for both species. Growth during the sea sojourn and return rates were positively correlated, linking increased survival with growth. Specific growth rate, survival, and duration of the sea sojourn of first-time migrants were correlated, suggesting that common environmental conditions at sea influence annual fish productivity. Freshwater and sea temperatures affected migration timing, whereas annual variation in marine growth and survival did not correlate with temperatures. This suggests that other factors such as variation in energy intake were the main source of annual growth variations. Moreover, the marine growth rate of the two species may signal annual overall fjord ecosystem production, especially related to their main prey.

Effect of Agricultural Seasons on Energy Intake: Evidence from Two Agro-Ecologically Different Rural Districts of India

Seasonality is recognised as a constraint to agricultural production and food and nutrition security of rural households. It alters the energy intake from different groups of foods based on the availability. These variations in energy intake affect the nutritional status of the population. Eight villages in Wardha district of Maharashtra state and eleven villages in Koraput district of Odisha state were purposefully selected for the study. Foods consumed by households were collected using a semi-quantitative questionnaire in three rounds in 2013-14 and 2014-15 to cover the lean (January-April), planting (May-August) and harvest (September-December) periods in agriculture. Cereals (wheat and rice), pulses, roots and tubers, fats and sugars were consumed daily in Wardha. In Koraput, the daily diet included cereals (rice and finger millet), other vegetables, fats and sugars. Cereals supplied majority of the total energy intake in both the study area (63% in Wardha and 85% in Koraput); the contribution is higher during lean period in Wardha and during planting in Koraput. Significant variation was found in the mean intake of food groups and the energy obtained from them between seasons except for few food groups. It was found to be positive during the planting season in Koraput and negative during lean period and harvest season when compared with the average energy intake across three seasons; in Wardha, energy intake was positive during harvest season followed by lean and was negative during planting season. It was also found that most small land holders (<2 ha) were affected by seasonality. The sourcing of foods and the energy contributed by them to the total energy intake also varied depending on seasons and majority of energy intake was sourced from public distribution system. Seasonality plays a crucial role in energy intake of individuals through fluctuation in availability and accessibility of food; this in turn will impact the nutritional status of the rural population. Energy requirement varies according to seasons as the type of agriculture activity differs. It is important to take seasonality into consideration while designing food-based approaches to combat the problem of undernutrition.

A simple method for identification of misreporting of energy intake from infancy to school age: Results from a longitudinal study

Misreporting is a major source of reporting bias in nutritional surveys. It can affect the analysis of associations between diet and disease. Although various methods have been proposed toidentify misreporting, their application to infants and young children is difficult. We identify misreporting of energy intake in infants and young children and propose a simplified approach. 1199 children were enrolled in the Childhood Obesity Programme (CHOP) based in 5 European countries (Belgium, Germany, Italy, Poland and Spain) with repeated measurements of 3-day weighed food protocol and anthropometric indices at 10 time points between ages 1-96 months. Individual cut-offs for the ratio of reported energy intake and estimated energy requirement were calculated to identify misreporters. Misreporting was studied according to age, gender, BMI z-scores and country. We identified a higher proportion of over-reporters (18.9%) as compared to under-reporters (10.6%). The proportion of over-reporting was higher among infants while under-reporting was more prevalent in school-aged children. Under-reporting was higher in boys (12.0%) and in obese/over-weight children (36.3%). Mean values for upper and lower cut-offs for the ratio of reported energy intake and estimated energy requirement in children≤12months were 0.80 and 1.20, and 0.75 and 1.25 for children>12months, respectively. Using these fixed (mean) values, 90.4% (kappa statistic: 0.78) of all misreporters could be identified. Despite intensive measures to obtain habitual intake of children, an essential proportion of nutritional reports were found to be implausible. Both over- and under-reporting should be carefully analysed, even in studies on infants. Fixed cut-offs can be applied to identify misreporting if no individual variation in energy intake can be calculated. This trial was registered at https://clinicaltrials.gov/show/NCT00338689.

0198 THE EFFECTS OF SLEEP RESTRICTION ON FOOD INTAKE: THE IMPORTANCE OF INDIVIDUAL CHARACTERISTICS

Acute sleep restriction (SR) often leads to an increase in energy intake (EI). However, large variability in food intake is often observed, which suggests that individual factors may affect EI after SR. The objective of this study was to explore the influence of personality traits (excitement seeking, impulsiveness and sense of competence), implicit attitudes toward food, and sensitivity to reward and punishment on EI after sleep loss. Seventeen subjects (11men; 18-33y) completed a personality inventory (NEO-PI-3), an Implicit Association Test (IAT; this test measures implicit attitudes toward healthy and unhealthy foods), and the Sensitivity to Punishment and Sensitivity to Reward Questionnaire (SPSRQ). Ad libitum EI over 24h was assessed following an habitual sleep night and a 50% SR held during the second half of the night. The difference in EI between sleep conditions (∆EI) was calculated for each subject. Correlations between ∆EI and subscales of the NEO-PI-3, IAT score and SPSRQ scores were computed. A multiple linear regression model was performed to examine the unique contribution of each variable that was significantly associated with ∆EI. We controlled for gender, resting energy expenditure and fat% in these analysis. ∆EI was associated with excitement seeking (r=-0.70, p<0.01) and IAT score (r=0.70, p<0.01), suggesting that less excitement seeking and more positive attitudes towards unhealthy food lead to greater EI after SR. Impulsiveness, sense of competence and SPSRQ scores were not associated with ∆EI. Multiple linear regression modeling demonstrated that excitement seeking and implicit attitudes collectively explain 62% of the variance in EI after SR (p<0.001). Excitement seeking was the largest predictor (β=-0.63, p<0.01), followed by implicit attitudes (β=0.40, p<0.05). These results suggest that excitement seeking and implicit attitudes toward food are key factors in explaining variations in EI after sleep loss. Since implicit attitudes are strongly related to educational and personal beliefs/values and personality traits are shaped by early life experiences which tend to remain stable over time, addressing weight gain issues in sleep restriction settings (e.g. rotating shifts) may be more challenging than simply addressing eating behaviors.

Spatial and Temporal Consumption Dynamics of Trout in Catch‐and‐Release Areas in Arkansas Tailwaters

AbstractRestrictive angling regulations in tailwater trout fisheries may be unsuccessful if food availability limits energy for fish to grow. We examined spatial and temporal variation in energy intake and growth in populations of Brown Trout Salmo trutta and Rainbow Trout Oncorhynchus mykiss within three catch‐and‐release (C‐R) areas in Arkansas tailwaters to evaluate food availability compared with consumption. Based on bioenergetic simulations, Rainbow Trout fed at submaintenance levels in both size‐classes (≤400 mm TL, &gt;400 mm TL) throughout most seasons. A particular bottleneck in food availability occurred in the winter for Rainbow Trout when the daily ration was substantially below the minimum required for maintenance, despite reduced metabolic costs associated with lower water temperatures. Rainbow Trout growth rates followed a similar pattern to consumption with negative growth rates during the winter periods. All three size‐classes (&lt;250 mm TL, 250–400 mm TL, &gt;400 mm TL) of Brown Trout experienced high growth rates and limited temporal bottlenecks in food availability. We observed higher mean densities for Rainbow Trout (47–342 fish/ha) than for Brown Trout (3–84 fish/ha) in all C‐R areas. Lower densities of Brown Trout coupled with an ontogenetic shift towards piscivory may have allowed for higher growth rates and sufficient consumption rates to meet energetic demands. Brown Trout at current densities were more effective in maintaining adequate growth rates and larger sizes in C‐R areas than were Rainbow Trout. Bioenergetic simulations suggest that reducing stocking levels of Rainbow Trout in the tailwaters may be necessary in order to achieve increased catch rates of larger trout in the C‐R areas.Received August 31, 2016; accepted January 9, 2017 Published online March 21, 2017