Do emotions predict eating? The role of previous experiences in emotional eating in the lab and in daily life.

Emotional eating is defined as an increase in eating following negative emotion. Self-reported emotional eating has been associated with physical health concerns. However, experimental and daily diary studies indicate that induced or naturally experienced negative emotions do not reliably lead to increased eating behavior in people without eating disorders, not even among self-professed emotional eaters. Emotional eating may depend on associations people have made between specific emotions and eating. We describe a set of studies with the overarching goal of determining whether accounting for the variation in people's associations between eating and different discrete emotions is the key to observing emotional eating. In both Study 1 (N = 118) and 2 (N = 111), we asked people to report on their tendency to eat following sadness and anxiety and determined how much they ate when induced to feel sad or anxious in the lab (Study 1) or experiencing these emotions in daily life (Study 2). We found no support for our hypotheses in either study; self-professed sad- or anxious-eaters did not eat more when induced to experience these emotions in the lab, or when experiencing these emotions in daily life. Thus, accounting for the variation in people's associations between eating and two discrete emotions, sadness and anxiety, is not the key to observing sad or anxious eating behavior in the lab or in daily life. Preregistration, materials, data, and code: https://osf.io/kcqej/ (Study 1) and https://osf.io/3euvg/ (Study 2).

Relationships between use of dietary supplements, caffeine and sensation seeking among college students.

Objective: Caffeine and dietary supplement (DS) use by college students is not well-documented. Given reported associations between energy drink consumption and sensation seeking, we used the Sensation Seeking Scale Form V (SSS-V) to assess relationships between sensation-seeking, caffeine, and DS use. Participants: Data from 1,248 college students from five US institutions were collected from 2009 to 2011. Methods: Linear regression was used to examine relationships between scores on the SSS-V and caffeine and DS use, demographic, and lifestyle characteristics. Results: Male sex, nonHispanic race-ethnicity, higher family income, tobacco use, consuming caffeinated beverages, more than 400 mg caffeine per day, and energy drinks with alcohol at least 50% of the time, were significantly associated with higher total SSS-V scores (P < 0.001). Those using protein DSs had higher total, disinhibition, and boredom susceptibility SSS-V scores (Ps < 0.001). Conclusions: Results demonstrate a positive correlation between sensation-seeking attitudes and habitual caffeine, energy drink, and DS consumption.

Endurance Exercise Enhances Emotional Valence and Emotion Regulation.

Acute exercise consistently benefits both emotion and cognition, particularly cognitive control. We evaluated acute endurance exercise influences on emotion, domain-general cognitive control and the cognitive control of emotion, specifically cognitive reappraisal. Thirty-six endurance runners, defined as running at least 30 miles per week with one weekly run of at least 9 miles (21 female, age 18-30 years) participated. In a repeated measures design, participants walked at 57% age-adjusted maximum heart rate (HRmax; range 51%-63%) and ran at 70% HRmax (range 64%-76%) for 90 min on two separate days. Participants completed measures of emotional state and the Stroop test of domain-general cognitive control before, every 30 min during and 30 min after exercise. Participants also completed a cognitive reappraisal task (CRT) after exercise. Functional near-infrared spectroscopy (fNIRS) tracked changes in oxygenated and deoxygenated hemoglobin (O2Hb and dHb) levels in the prefrontal cortex (PFC). Results suggest that even at relatively moderate intensities, endurance athletes benefit emotionally from running both during and after exercise and task-related PFC oxygenation reductions do not appear to hinder prefrontal-dependent cognitive control.

Sugar intake and expectation effects on cognition and mood.

Glucose intake has been found to improve some aspects of cognitive performance; however, results are often inconsistent. This inconsistency may be related to expectations surrounding glucose, which can have strong effects on performance outcomes. The present study evaluated the independent and interactive effects of acute sugar intake, in the form of high-fructose corn syrup (HFCS), and sugar expectancies on cognitive performance and mood. One hundred five healthy young adults were randomized according to sugar intake and expectation: consumed-sugar/told-sugar, consumed-sugar/told-no-sugar, consumed-no-sugar/told-sugar, and consumed-no-sugar/told-no-sugar. Thirty minutes after sugar or no-sugar intake, participants completed the Profile of Mood States and a battery of cognitive tests, including immediate and delayed recall, the Stroop test, n-back task, and continuous performance task. Tension increased following the expectation of consuming sugar, regardless of sugar consumption (p < .05). On the continuous performance task, accuracy and sensitivity were higher (ps < .05) and false alarm rate was lower (p < .05) following sugar than no sugar intake. No effects of sugar intake or expectation were found for any other mood or cognitive measure (ps > .05). The findings suggest that sugar intake in the form of HFCS may benefit certain cognitive processes, such as those that require sustained attention, but that the expectation of sugar intake is not sufficient to produce such benefits. (PsycINFO Database Record

Breakfast food health and acute exercise: Effects on state body image.

Food intake and exercise have been shown to alter body satisfaction in a state-dependent manner. One-time consumption of food perceived as unhealthy can be detrimental to body satisfaction, whereas an acute bout of moderate-intensity aerobic exercise can be beneficial. The current study examined the effect of exercise on state body image and appearance-related self-esteem following consumption of isocaloric foods perceived as healthy or unhealthy in 36 female college students (18-30 years old) in the Northeastern United States. Using a randomized-controlled design, participants attended six study sessions with breakfast conditions (healthy, unhealthy, no food) and activity (exercise, quiet rest) as within-participants factors. Body image questionnaires were completed prior to breakfast condition, between breakfast and activity conditions, and following activity condition. Results showed that consumption of an unhealthy breakfast decreased appearance self-esteem and increased body size perception, whereas consumption of a healthy breakfast did not influence appearance self-esteem but increased body size perception. Exercise did not influence state body image attitudes or perceptions following meal consumption. Study findings suggest that morning meal type, but not aerobic exercise, influence body satisfaction in college-aged females.

Caffeine alters emotion and emotional responses in low habitual caffeine consumers.

Caffeine reliably increases emotional arousal, but it is unclear whether and how it influences other dimensions of emotion such as emotional valence. These experiments documented whether caffeine influences emotion and emotion regulation choice and success. Low to abstinent caffeine consumers (maximum 100 mg/day) completed measures of state anxiety, positive and negative emotion, and salivary cortisol before, 45 min after, and 75 min after consuming 400 mg caffeine or placebo. Participants also completed an emotion regulation choice task, in which they chose to employ cognitive reappraisal or distraction in response to high and low intensity negative pictures (Experiment 1), or a cognitive reappraisal task, in which they employed cognitive reappraisal or no emotion regulation strategy in response to negative and neutral pictures (Experiment 2). State anxiety, negative emotion, and salivary cortisol were heightened both 45 and 75 min after caffeine intake relative to placebo. In Experiment 1, caffeine did not influence the frequency with which participants chose reappraisal or distraction, but reduced negativity of the picture ratings. In Experiment 2, caffeine did not influence cognitive reappraisal success. Thus, caffeine mitigated emotional responses to negative situations, but not how participants chose to regulate such responses or the success with which they did so.

Habitual exercise is associated with cognitive control and cognitive reappraisal success.

Habitual exercise is associated with enhanced domain-general cognitive control, such as inhibitory control, selective attention, and working memory, all of which rely on the frontal cortex. However, whether regular exercise is associated with more specific aspects of cognitive control, such as the cognitive control of emotion, remains relatively unexplored. The present study employed a correlational design to determine whether level of habitual exercise was related to performance on the Stroop test measuring selective attention and response inhibition, the cognitive reappraisal task measuring cognitive reappraisal success, and associated changes in prefrontal cortex (PFC) oxygenation using functional near-infrared spectroscopy. 74 individuals (24 men, 50 women, age 18-32 years) participated. Higher habitual physical activity was associated with lower Stroop interference (indicating greater inhibitory control) and enhanced cognitive reappraisal success. Higher habitual exercise was also associated with lower oxygenated hemoglobin (O2Hb) in the PFC in response to emotional information. However, NIRS data indicated that exercise was not associated with cognitive control-associated O2Hb in the PFC. Behaviorally, the findings support and extend the previous findings that habitual exercise relates to more successful cognitive control of neutral information and cognitive reappraisal of emotional information. Future research should explore whether habitual exercise exerts causal benefits to cognitive control and PFC oxygenation, as well as isolate specific cognitive control processes sensitive to change through habitual exercise.

Impaired reversal learning in an animal model of anorexia nervosa.

BACKGROUND: Clinical investigations indicate that anorexia nervosa (AN) is associated with impaired cognitive flexibility. Activity-based anorexia (ABA), a rodent behavioral model of AN, is characterized by compulsive wheel running associated with voluntary food restriction and progressive weight loss. The goal of this study was to test whether ABA is associated with impaired cognitive flexibility. METHODS: Female Sprague-Dawley rats were trained to perform the attentional set-shifting test (ASST) to assess cognitive flexibility, including capacity for set-shifting and reversal learning. Rats were assigned to ABA or weight-loss paired control (WPC) conditions. Following baseline testing, the ABA group had access to food for 1h/d and access to running wheels 23h/d until 20% weight loss was voluntarily achieved. For the WPC group, running wheels were locked and access to food was restricted to reduce body weight at the same rate as the ABA group. ASST performance was assessed after weight loss, and again following weight recovery. RESULTS: Compared to baseline, the ABA group (but not the WPC group) showed a significant decrement in reversal learning at low weight, with return to baseline performance following weight restoration. The other components of ASST were not affected. CONCLUSIONS: Impaired reversal learning, indicative of increased perseverative responding, in the ABA model reveals its potential to recapitulate selective components of cortical dysfunction in AN. This finding supports the utility of the ABA model for investigations of the neural mechanisms underlying such deficits. Reversal learning relies on neural circuits involving the orbitofrontal cortex and thus the results implicate orbitofrontal abnormalities in AN-like state.

Caffeine and theanine exert opposite effects on attention under emotional arousal.

Tea is perceived as more relaxing than coffee, even though both contain caffeine. L-theanine in tea may account for the difference. Consumed together, caffeine and theanine exert similar cognitive effects to that of caffeine alone, but exert opposite effects on arousal, in that caffeine accentuates and theanine mitigates physiological and felt stress responses. We evaluated whether caffeine and theanine influenced cognition under emotional arousal. Using a double-blind, repeated-measures design, 36 participants received 4 treatments (200 mg caffeine + 0 mg theanine, 0 mg caffeine + 200 mg theanine, 200 mg caffeine + 200 mg theanine, 0 mg caffeine + 0 mg theanine) on separate days. Emotional arousal was induced by highly arousing negative film clips and pictures. Mood, salivary cortisol, and visual attention were evaluated. Caffeine accentuated global processing of visual attention on the hierarchical shape task (p < 0.05), theanine accentuated local processing (p < 0.05), and the combination did not differ from placebo. Caffeine reduced flanker conflict difference scores on the Attention Network Test (p < 0.05), theanine increased difference scores (p < 0.05), and the combination did not differ from placebo. Thus, under emotional arousal, caffeine and theanine exert opposite effects on certain attentional processes, but when consumed together, they counteract the effects of each other.

The impact of caffeine use across the lifespan on cognitive performance in elderly women.

Habitual caffeine consumption has often been associated with decreasing age-related cognitive decline. However, whether habitual caffeine use preferentially spares different cognitive processes is unclear. Furthermore, whether basing habitual caffeine consumption patterns on current consumption or on a lifetime measure better represents an individual's use remains unclear. In the present study, we collected information from women, aged 56-83, about their current caffeine consumption patterns and history of use, including age they began consuming caffeine. Regression models assessed the relationship between caffeine consumption and performance on batteries designed to probe speed of processing, inhibition, memory, and executive function. While we found no direct associations between caffeine exposure and cognitive performance, we found that caffeine consumption and participant BMI interacted for inhibitory function and speed of processing performance. We discuss possible protective effects of long term caffeine use as well as the possibility of dose dependent effects.

Omega-3 fatty acids and stress-induced changes to mood and cognition in healthy individuals.

Omega-3 fatty acid (n-3 PUFA) intake is associated with improved mood and cognition, but randomized controlled trials addressing the causal nature of such relationships are less clear, especially in healthy, young adults. Stress is one potential mechanism by which n-3 PUFAs may influence mood. Thus the present aim is to evaluate the influence of n-3 PUFA supplementation on stress-induced changes to mood, cognition, and physiological stress markers in healthy, young adults. Using a double-blind, placebo-controlled design, 72 young adults were randomized to receive 2800mg/day fish oil (n=36, 23 females) or olive oil control (n=36, 22 females) for 35days. Subjects completed measures of mood and cognition before supplementation, and two times after supplementation: following an acute stressor or non-stressful control task. The stress induction was effective in that the stressor impaired mood, including augmenting feelings of tension, anger, confusion and anxiety, reduced accuracy on a cognitive task measuring attentional control and the ability to regulate emotion, and increased salivary cortisol and pro-inflammatory cytokine interleukin-1ß (IL-1ß). Rated anger and confusion increased with stress in the olive oil group, but remained stable in the fish oil group. However, fish oil had no further effects on mood, cognitive function, cortisol, or IL-1ß. Fish oil exerted few effects in stressful and non-stressful situations, consistent with findings showing little influence of n-3 PUFA supplementation on mood and cognition in young, healthy individuals. Potential target populations who would more likely benefit from increased n-3 PUFA intake are discussed.

Chronic high-dose creatine has opposing effects on depression-related gene expression and behavior in intact and sex hormone-treated gonadectomized male and female rats.

Creatine is an antioxidant, neuromodulator and key regulator of energy metabolism shown to improve depressive symptoms in humans and animals, especially in females. To better understand the pharmacological effects of creatine, we examined its influence on depression-related hippocampal gene expression and behaviors in the presence and absence of sex steroids. Sham-operated and gonadectomized male and female rats were fed chow alone or chow blended with either 2% or 4% w/w creatine monohydrate for five weeks before forced swim, open field, and wire suspension tests, or seven weeks total. Before supplementation, males were chronically implanted with an empty or a testosterone-filled (T) capsule (10-mm surface release), and females were administered progesterone (P, 250 µg), estradiol benzoate (EB, 2.5 µg), EB+P, or sesame oil vehicle weekly. Relative to non-supplemented shams, all hippocampal plasticity-related mRNAs measured, including brain-derived neurotrophic factor (BDNF), tyrosine kinase B, doublecortin, calretinin, and calbindin, were downregulated in sham males given 4% creatine, and BDNF, doublecortin, and calbindin mRNAs were downregulated in sham females given 4% creatine. In contrast, combined 4% creatine+T in castrates prevented downregulation of BDNF, doublecortin, and calretinin mRNAs. Similarly, combined 4% creatine+EB+P in ovariectomized females attenuated downregulation of BDNF and calbindin mRNA levels. Moderate antidepressant and anxiolytic-like behaviors were observed in EB+P-treated ovariectomized females fed creatine, with similar trends in T-treated castrates fed creatine. Altogether, these data show that chronic, high-dose creatine has opposing effects on neuroplasticity-related genes and depressive behavior in intact and gonadectomized male and female rats. The dose and schedule of creatine used negatively impacted hippocampal neuronal integrity in otherwise healthy brains, possibly through negative compensatory changes in energy metabolism, whereas combined creatine and sex steroids acted in a neuroprotective manner in gonadectomized rats, potentially by reducing metabolic complications associated with castration or ovariectomy.

Stress effects on mood, HPA axis, and autonomic response: comparison of three psychosocial stress paradigms.

Extensive experimental psychology research has attempted to parse the complex relationship between psychosocial stress, mood, cognitive performance, and physiological changes. To do so, it is necessary to have effective, validated methods to experimentally induce psychosocial stress. The Trier Social Stress Test (TSST) is the most commonly used method of experimentally inducing psychosocial stress, but it is resource intensive. Less resource intense psychosocial stress tasks include the Socially Evaluative Cold Pressor Task (SECPT) and a computerized mental arithmetic task (MAT). These tasks effectively produce a physiological and psychological stress response and have the benefits of requiring fewer experimenters and affording data collection from multiple participants simultaneously. The objective of this study was to compare the magnitude and duration of these three experimental psychosocial stress induction paradigms. On each of four separate days, participants completed either a control non-stressful task or one of the three experimental stressors: the TSST, SECPT, or MAT. We measured mood, working memory performance, salivary cortisol and alpha-amylase (AA), and heart rate. The TSST and SECPT exerted the most robust effects on mood and physiological measures. TSST effects were generally evident immediately post-stress as well as 10- and 20-minutes after stress cessation, whereas SECPT effects were generally limited to the duration of the stressor. The stress duration is a key determinant when planning a study that utilizes an experimental stressor, as researchers may be interested in collecting dependent measures prior to stress cessation. In this way, the TSST would allow the investigator a longer window to administer tasks of interest.

Acute exercise increases oxygenated and deoxygenated hemoglobin in the prefrontal cortex.

Both acute and chronic exercise is consistently associated with a number of benefits to physical and mental health, including cardiovascular function, body weight, mood, and cognition. Near-infrared spectroscopy is an ideal method to measure changes in oxygenated and deoxygenated hemoglobin (O2Hb and dHb) levels in the prefrontal cortex (PFC) during exercise, to better understand the locus of such changes in affective and cognitive processes. The present study tracked time-dependent changes in O2Hb and dHb levels in the PFC as a function of parametrically manipulated target exercise intensity. Near-infrared spectroscopy was conducted as regular exercisers completed a 30-min bout of exercise with one of three target intensities: 52% (low condition), 68% (moderate condition), or 84% (high condition) of age-adjusted maximum heart rate. Heart rate data confirmed that the participants reached their goal intensities immediately, after 10 min, or after 20 min, respectively. Data showed that O2Hb and dHb levels in the PFC increased as a function of both exercise load and duration. An 84%>68%>52% difference was evident after 18 min of cycling for O2Hb and after 23 min of cycling for dHb. The present results add to the growing body of literature showing that at submaximal levels, increasing exercise intensities reliably promote prefrontal cerebral oxygenation.

Central and peripheral relationships between morphine and glucose on antinociception in rats.

Previous research from our laboratory has determined that in the absence of a gustatory response or taste hedonics, intraperitoneal (i.p.) glucose administration enhanced morphine-mediated analgesia in rats and had antinociceptive actions on its own. Two experiments examined the potential of a central mechanism for glucose's actions on morphine-mediated antinociception. Morphine (2.5 µg) was infused into the periaqueductal gray (PAG) while glucose (300 mg/kg) was injected into the peritoneal cavity, or glucose (32 nmol) was infused into the PAG while morphine (3.2 mg/kg) was injected i.p. Doses of morphine and glucose were selected based on our own prior research for being below the threshold for analgesic efficacy. Antinociception was assessed using the hot-water tail-withdrawal procedure. Tail-withdrawal latency was tested at baseline (before), and 12, 24 and 36 minutes after the i.p. injection. The results indicated that 300 mg/kg glucose, administered i.p. effectively increased the antinociceptive potency of a low dose of centrally administered morphine, while central infusion of glucose enhanced peripheral morphine-mediated antinociception. These outcomes support previous evidence of glucose's influence on the antinociception actions of opioid drugs. Furthermore, they suggest that glucose produces its enhancing actions on morphine-mediated antinociception in the brain. These results support the hypothesis that glucose does not need to go through a gustatory mechanism or taste hedonics to alter morphine's antinociceptive actions.

Antinociceptive actions of peripheral glucose administration.

The effects of intraperitoneal (ip) D-glucose administration on antinociception were studied in male Long-Evans rats. Rats were assessed for antinociception using the hot-water tail-withdrawal procedure (54±0.2 °C) to determine if peripheral administration of D-glucose (300, 560, or 720 mg/kg) would enhance morphine-mediated antinociception (MMA) (1.0, 3.0, 4.2, 5.6, and 10.0mg/kg cumulative-dosing regime) and if D-glucose (560, 720, or 1000 mg/kg) alone could produce antinociceptive activity that was naloxone (0.32 mg/kg) reversible. Additionally, the actions of D-glucose on MMA were compared with a stereoisomer, L-glucose, which is not metabolized. The results of these studies demonstrate that peripheral administration of D-glucose significantly enhances MMA and that D-glucose alone produces antinociceptive actions that are potentially mediated by the endogenous opioid system. Furthermore, L-glucose failed to have an effect on MMA suggesting that the alterations in antinociception seen with D-glucose are not due to stressors such as osmolality or injection. The current studies provide evidence that D-glucose alteration of antinociception is not simply a response to taste or gustation.

Caffeine promotes global spatial processing in habitual and non-habitual caffeine consumers.

Information processing is generally biased toward global cues, often at the expense of local information. Equivocal extant data suggests that arousal states may accentuate either a local or global processing bias, at least partially dependent on the nature of the manipulation, task, and stimuli. To further differentiate the conditions responsible for such equivocal results we varied caffeine doses to alter physiological arousal states and measured their effect on tasks requiring the retrieval of local versus global spatial knowledge. In a double-blind, repeated-measures design, non-habitual (Experiment 1; N = 36, M = 42.5 ± 28.7 mg/day caffeine) and habitual (Experiment 2; N = 34, M = 579.5 ± 311.5 mg/day caffeine) caffeine consumers completed four test sessions corresponding to each of four caffeine doses (0, 100, 200, 400 mg). During each test session, participants consumed a capsule containing one of the three doses of caffeine or placebo, waited 60 min, and then completed two spatial tasks, one involving memorizing maps and one spatial descriptions. A spatial statement verification task tested local versus global spatial knowledge by differentially probing memory for proximal versus distal landmark relationships. On the map learning task, results indicated that caffeine enhanced memory for distal (i.e., global) compared to proximal (i.e., local) comparisons at 100 (marginal), 200, and 400 mg caffeine in non-habitual consumers, and marginally beginning at 200 mg caffeine in habitual consumers. On the spatial descriptions task, caffeine enhanced memory for distal compared to proximal comparisons beginning at 100 mg in non-habitual but not habitual consumers. We thus provide evidence that caffeine-induced physiological arousal amplifies global spatial processing biases, and these effects are at least partially driven by habitual caffeine consumption.

Get in my belly: food preferences trigger approach and avoidant postural asymmetries.

Appetitive motivational states are fundamental neural and behavioral mechanisms underlying healthy and abnormal eating behavior, though their dynamic influence on food-related behavior is unknown. The present study examined whether personal food-related preferences would activate approach and avoidance systems, modulating spontaneous postural sway toward and away from food items. Participants stood on a balance board that collected real-time data regarding postural sway along two axes (x, y) while they viewed a series of images depicting food items varying in nutritional value and individual preferences. Overall, participants showed reliable postural sway toward highly preferred and away from highly non-preferred items. This effect became more pronounced over time; sway along the mediolateral axis showed no reliable variation by preference. Results carry implications for two-factor (homeostatic versus hedonic) neurobehavioral theories of hunger and appetitive motivation, and carry applied clinical implications for the measurement and management of abnormal eating behavior.

Omega-3 fatty acids influence mood in healthy and depressed individuals.

Depression is one of the most prevalent disorders in the United States, and rates of depression are higher for women than men. Despite their widespread use, drugs used in the treatment of depression are only moderately more effective than placebo in treating the disorder. Effective treatment of perinatal depression is of particular concern as treatment can influence both the mother and the developing child. Omega-3 polyunsaturated fatty acid (n-3 PUFA) supplementation may reduce symptoms of major depressive disorder and perinatal depression. The aim of the present review was to evaluate epidemiological studies examining PUFA intake and depressive symptoms in the general population, as well as double-blind, placebo-controlled trials assessing the influence of n-3 PUFA in healthy individuals and those with depression; specific consideration was given to perinatal depression and potential gender differences in the relationship. Although there is some evidence to suggest that n-3 PUFA intake is associated with reduced depressive symptoms, particularly in females, these results are generally limited to epidemiological studies, whereas results from randomized controlled trials are mixed.

Differential cognitive effects of energy drink ingredients: caffeine, taurine, and glucose.

Energy drinks containing caffeine, taurine, and glucose may improve mood and cognitive performance. However, there are no studies assessing the individual and interactive effects of these ingredients. We evaluated the effects of caffeine, taurine, and glucose alone and in combination on cognitive performance and mood in 24-hour caffeine-abstained habitual caffeine consumers. Using a randomized, double-blind, mixed design, 48 habitual caffeine consumers (18 male, 30 female) who were 24-hour caffeine deprived received one of four treatments (200 mg caffeine/0 mg taurine, 0 mg caffeine/2000 mg taurine, 200 mg caffeine/2000 mg taurine, 0 mg caffeine/0 mg taurine), on each of four separate days, separated by a 3-day wash-out period. Between-participants treatment was a glucose drink (50 g glucose, placebo). Salivary cortisol, mood and heart rate were measured. An attention task was administered 30-minutes post-treatment, followed by a working memory and reaction time task 60-minutes post-treatment. Caffeine enhanced executive control and working memory, and reduced simple and choice reaction time. Taurine increased choice reaction time but reduced reaction time in the working memory tasks. Glucose alone slowed choice reaction time. Glucose in combination with caffeine, enhanced object working memory and in combination with taurine, enhanced orienting attention. Limited glucose effects may reflect low task difficulty relative to subjects' cognitive ability. Caffeine reduced feelings of fatigue and increased tension and vigor. Taurine reversed the effects of caffeine on vigor and caffeine-withdrawal symptoms. No effects were found for salivary cortisol or heart rate. Caffeine, not taurine or glucose, is likely responsible for reported changes in cognitive performance following consumption of energy drinks, especially in caffeine-withdrawn habitual caffeine consumers.