Diet and Sport Psychology

While dieting may help athletes gain desirable body composition parameters that could improve physical performance, it could also cause disordered eating (DE) habits that may progress to fully-fledged eating disorders. In this cross-sectional study by Graybeal et al. (2022), the authors investigated the behavioral patterns surrounding diet culture in endurance athletes and attempted to identify potential sex differences amongst a sample of 231 endurance athletes (females n = 124). Participants submitted questionnaires regarding their dietary patterns and relevant study variables, revealing that only 29.9% of athletes followed a dietary plan. Females who didn’t follow a dietary plan had higher odds of going on a diet at least once (n = 162). Male athletes on a dietary plan were more inclined to consume a balanced diet, while their female counterparts leaned towards following a plant-based dietary plan. Females had higher odds of attempting a dietary plan compared to males, had higher odds of attempting ≥ three diets, and were more prone to low-carbohydrate, energy-restricted, ketogenic, and gluten-/dairy-free diets exclusively (22% females vs. 0% males), compared to their male counterparts. The most commonly adopted dietary plans were plant-based, carbohydrate/energy-restrictive, and elimination diets. The authors conclude that sex plays a major role in the frequency of going on diets and on following restrictive dietary trends, findings that should be accounted for by coaches and sports dieticians to help support athletes and tailor proper interventions for female athletes. [NPID: Disordered eating behaviors, eating disorders, endurance training, female athlete nutrition, sports nutrition]

In this qualitative research study by Carson et al. (2021), the authors compared body image perception, eating disorders, and the impact of emerging coach-athlete power dynamics in a sample of past and current National Collegiate Athletic Association (NCAA) Division One (DI) female distance runners. Study participants (current and past NCAA D1 female distance runners competing at 800 meters or greater, n = 29) were interviewed and their responses were recorded, revealing two main themes. Firstly, there was a widespread perception of what constitutes an ideal body image, in addition to myths related to physique, and secondly, that a coach-athlete power dynamic did exist. The interplay between these two themes remains unclear, however, the authors speculate that they influence each other and play a role in cementing the currently adopted perceptions by athletes and coaches. The authors conclude that the coach-athlete power dynamic may contribute to eating disorders and negative body image perception in female athletes, raising the need for NCAA and athletic departments to fashion effective interventions to combat these phenomena in the vulnerable female athlete population. [NPID: Eating disorder, female athlete triad, qualitative, running, women in sport]

Dietary interventions have been proven to play a role in enhancing mental health. The International Olympic Committee recognizes the mental health of athletes as a key contributor to collegiate athletes’ safety and physical health. Female collegiate athletes have a higher propensity for nutritional irregularities, depression, and anxiety. The degree of evidence surrounding this vulnerable population remains insufficient, thus, Christensen et al. (2021) conducted their quantitative, cross-sectional studies to investigate female athletic students. A final sample of 77 female athletes submitted a validated, web-based Diet History Questionnaire (DHQ-III) to extrapolate a Healthy Eating Index (HEI), in addition to a total of three mental health questionnaires: the Athlete Psychological Strain Questionnaire (APSQ), COVID Stress Scales (CSS), and the Depression Anxiety and Stress Scale (DASS-21). Data analysis revealed a negative association between HEI scores and mental health, where athletes scoring high on the HEI were found to suffer from higher levels of performance concerns, stress, poor mental health, and elevated CSS components (contamination, danger, and traumatic stress). In opposition to the original authors’ hypotheses, a substantial relationship was observed between mental health and dietary quality, in addition to stress indicators and levels of symptom severity particular to COVID-19 and athletes. Thus, the authors recommend conducting further studies to fully understand these findings. [NPID: COVID-19, Healthy Eating Index, collegiate athletes, diet quality, female, mental health, nutrition, stress]

Athletes are prone to suffer from sleep disruption and poor quality of sleep due to their occupational circumstances, including muscle fatigue, constant and/or long term travel, scheduled exercise and competition times (during the early hours of the morning or evening). Nutrition is paramount for performance, workout and post-workout recovery. Ensuring a diverse diet and adequate nutritional supplementation may give athletes the best chances to improve both quality and quantity of sleep. In this narrative review, Gratwicke et al. (2021) discuss studies relevant to athletes that investigate nutrition, supplements, and beverages that may improve sleep quality and quantity. Six databases were searched for relevant literature from November 2020 up to study initiation. Due to the lack of literature investigating the subpopulation of athletes, inclusion criteria for relevant studies were increased to allow review of studies that investigated healthy adults, regardless of athletic status. The results demonstrated that foods with a high glycemic index somewhat improved sleep, and that tart cherry juice enhanced sleep quantity, while herbal supplements improved sleep quality. Interestingly, kiwifruit and protein supplements improved both sleep quality and quantity. The authors comment that nutritional interventions may present an efficient method to target sleep quality and quantity, however, more research is required to understand dosing, nutritional sources and timing of interventions with respect to training, travel, and competitions. [NPID: sleep, athletes, recovery, team-sport, macronutrients, supplements]

In this study, Natàlia et al. (2022) examined how high (HGI) or low glycemic index (LGI) high-carbohydrate meals affected athletes' sleep quality. For the duration of two days during a basketball championship, nine male basketball players were given high-carbohydrate meals (dinner and evening snack) with HGI or LGI. Data on sleep was collected in both quantitative and qualitative measures, including sleep latency (LAT), sleep efficiency (EFIC), Wake After Sleep Onset (WASO), and sleep time, using actigraphy and sleep diary. Dietary intake, satiety, sleepiness, glycemic response, salivary cortisol and melatonin were among relevant parameters investigated for the study. The results revealed that the athletes scored higher on LAT and WASO and lower on nocturnal sleep time when compared to recommended scores. Although the athletes did not show any changes in sleep or hormonal levels in response to GI alterations, a relationship was seen between sleep and diet. Specifically, the amount of energy consumed per day was found to adversely affect sleep efficiency and nocturnal total sleep time and WASO favorably, regardless of meals consumed at night. However, no changes were seen in salivary cortisol and melatonin in response to GI. The authors comment that food eaten throughout the day affects sleep parameters of basketball athletes more significantly than altering the GI of meals eaten on the pre-game night, however, conducting more studies is paramount to further outline this complex interaction. [NPID: Sleep, glycemic index, athletes, dietetics]

In this 2016 study, cyclists undergoing intermittent fasting for Ramadan were assessed on their cognitive function. The participants fasted during the daylight hours. Various cognitive tests were conducted before and after Ramadan, and in the 1st and 4th weeks of this holy month of fasting. An increase in perceived fatigue and delayed onset muscle soreness was noticed in the 4th week of Ramadan. Moreover, the eleven cyclists showed disturbed sleeping patterns during Ramadan. Duration of light sleep and number of awakenings significantly increased during this period. Following the holy month, the study observed decreased durations of deep and REM sleep stages in the athletes. With regards to the cognitive tests, reaction and movement times did not vary over the study period. There were, however, higher incidences of false alarms in the Rapid Visual Information Processing (RVP) tests, suggesting reduced impulsivity. Compared to baseline, overall accuracy was higher during Ramadan (1st and 4th weeks) and post-Ramadan. In the fourth week of fasting, accuracy was higher at 0-2 am compared to 4-6pm. In conclusion, the intermittent fasting that takes place during Ramadan did not negatively affect the cognitive performance of trained cyclists from the Middle East. [NPID: fasting, intermittent fasting, Ramadan, Middle East, Muslim, cyclists, athletes, cognition, sleep]

The aim of this 2021 research study was to examine the effects of a nutritional supplement on inflammatory and stress biomarkers among professional athletes and inactive people. This test supplement was called Gasteel Plus and contained both probiotics and prebiotics. The trial also evaluated its impact on parameters related to physical and mental health, such as metabolic profile and physical activity. The study participants included professional football players in the Second Division B of the Spanish League, and sedentary students. These subjects were randomly chosen to receive either a placebo (the control group) or the synbiotic (experimental group). The synbiotic supplement (Gasteel Plus) was found to improve physical activity, sleep quality, and perceived general health, stress, and anxiety levels but only among the athletes. Furthermore the synbiotic appeared to affect certain inflammatory/immune and stress biomarkers such as dopamine, interleukin-1β, and corticotropin-releasing hormone (CRH) but the exact effects depended on the baseline readings. To summarize, synbiotic nutritional supplements can enhance anxiety, stress, and sleep quality, especially in sportspeople. [NPID: anxiety, stress, sleep quality, synbiotic, probiotic, prebiotic, supplements, diet, nutrition, inflammation, athletes, sports psychology]

This 2020 study recruited both men and women wrestlers in Turkey to analyze the relationship between emotional eating and mindfulness among active wrestlers. Data was collected from 382 volunteering wrestlers by handing out personal information forms and applying the Emotional Eating Scale as well as the Mindfulness Inventory for Sport. On average, the national wrestlers ate more food types than non-national athletes and were rated higher in guilt and emotional eating. Higher scores in the Mindfulness Inventory were related to less ability to refocus. Greater disinhibition was also connected to reduced awareness. The study found that guilt, non-judgment, refocusing, and the Mindfulness Inventory scores were positively linked, although the relationship was weak. A weak negative correlation was identified between the participants’ emotional eating scales, awareness, ability to refocus, and non-judgment. The author Şahin concludes that the physically and psychologically negative effects of emotional eating may contribute to reduced levels of awareness in athletes. [NPID: sports psychology, wrestlers, Turkey, athletes, emotional eating, mindfulness]

The purpose of this 2020 study was to find out if the social skills of a trainer can influence aspects of the athletes’ psychological health and diet. Trigueros et al. kept an eye on the athletes’ coping capacity, psychological well-being, and eating habits since these factors are important for athletes to achieve success during competition. The study managed to sign up 1547 athletes and 127 trainers. Positive correlations were found between trainers’ prosocial behaviors and athletes’ resilience. Conversely, increased antisocial behaviors were linked with poorer resilience. Those with greater resilience showed lower probability of having anxiety, stress, and depression, but having lower resilience tended to mean higher risk. In addition, these psychological disorders were less prevalent in healthy eaters than in those with unhealthy diets. Overall, these findings highlight the importance of positive social environments in promoting mental health and healthy eating habits in athletes. [NPID: nutrition, sports psychology, resilience, social behaviors, trainers, athletes, anxiety, depression, stress, mental health]

This 2018 study investigates whether following a vegetarian or vegan diet can modulate quality of life in athletes. There is evidence indicating that these diet types can positively affect exercise performance in athletes, but there is limited data on its influence on well-being and psyche. This study examined the quality of life scores of endurance runners, and compared those who adhere to an omnivore diet with those who eat a vegetarian or vegan diet. The 281 runners (male and female) completed questionnaires that assessed physical health, psychological well-being, social relationships, and environmental conditions. More of the participants followed a vegetarian or vegan diet rather than an omnivore diet (158 vs. 123). The final analyses were performed on the 173 runners who met the inclusion criteria. Among this sample, there were 103 half-marathoners and 70 marathoners/ultramarathoners. The study also added a control group of 10km runners. The overall quality of life scores among the sample was high. Men were found to score higher than women overall due to the high scores in the physical health and psychological well-being dimensions. Eating an omnivore diet appeared to influence environmental scores among women, and affected social relationship scores among men. In summary, endurance runners showed high quality of life scores, regardless of the distance they run or diet choice. The vegetarian and vegan diet may be equal alternatives to the omnivore diet. [NPID: runners, athletes, vegetarian diet, vegan diet, healthy diets, quality of life, sports psychology, running, marathon running]

This 2016 study determined the prevalence rate of disordered eating among a sample of female college athletes by conducting several tests and surveys. Although experts have yet to confirm the factors that contribute to disordered eating in female college athletes, emotional regulation has been identified as a potential correlate. An aim of this study was to assess emotional regulation, body dissatisfaction, sport type, a family history of eating disorder, and BMI as potential predictors of disordered eating. One hundred and fifty-one female participants completed the Minnesota Eating Behavior Survey and the Eating Attitudes Test-26 to identify disordered eating. The results demonstrated different incidence rates depending on the assessments, but roughly 6.6 to 10.6% of the young athletes exhibited disordered eating. The prevalence rates of disordered eating did not vary by sport type (no difference between performers in weight-sensitive and less weight-sensitive sports). Another finding was that increased emotional regulation issues and body dissatisfaction were significant predictors of disordered eating. This revelation warrants further investigation of emotional control and dissatisfaction with respect to disordered eating in female college athletes. [NPID: college, athletes, sports psychology, emotional regulation, disordered eating, body dissatisfaction, sports nutrition]

In this 2013 study, a group of junior football players were asked how often they eat certain food items and were examined on their self-efficacy. The plan was to determine if there is a correlation between the young athletes’ self-efficacy and the frequency at which they consume specific food items. Just over 55% of the study participants reported moderate self-efficacy, while just below 45% were found to have high self-efficacy. Higher self-efficacy was related to more regular intake of whole wheat bread, brown rice, high-fat cottage cheese, and butter. Those who ate poultry meat, and olive and plant oils less frequently were more likely to have higher self-efficacy. When directly comparing athletes with high self-efficacy to athletes with moderate self-efficacy, those with higher self-efficacy selected whole wheat bread, brown and white rice, fruits, low-fat milk, high-fat cottage cheese, butter, and sweetened fizzy drinks more frequently. This subgroup of athletes with high self-efficacy also consumed poultry meat, pastries, and sweets less often than those with moderate self-efficacy. Based on these results, this study concludes that high self-efficacy promotes more balanced nutritional choices. [NPID: nutrition, athletes, sports psychology, football players, self-efficacy, nutritional choices, diet]

In this 2021 study, 13 university badminton players were randomly chosen to either receive a probiotic or a placebo drink for six weeks. The subjects’ fitness levels were monitored through various tests and exercises such as the 20-meter shuttle runs, handgrips, vertical jumps, 40-meter dash, and the T-test. In addition, the researchers wanted to determine the effect of taking probiotics on the badminton players’ competitive anxiety, perceived stress, and mood. These psychological outcomes were assessed by administering questionnaires. Anxiety and stress levels decreased considerably (by 16% and 21% respectively) in the probiotic group after 6 weeks. In contrast, there was no difference found in the placebo group. The athletes taking probiotics also demonstrated enhanced aerobic capacity during the intervention. But the probiotic supplementation did not seem to affect speed, strength, leg power, or agility. Benefits of taking probiotics included better aerobic capacity and less anxiety and stress. [NPID: athletic performance, anxiety, stress, mood, badminton players, university, probiotics]

The aim of this 2020 study was to determine the effect of taking probiotic supplements every day on anxiety-induced physiological characteristics among competitive football players. It is said that footballers who undergo intensive training and frequently compete in competitions are vulnerable to psychological disorders, while probiotics are believed to reduce the risk of developing these disorders. In this trial, the football players were either given probiotics or a placebo drink over 8 weeks, before being tested on outcomes such as cognition. In addition, the athletes had their heart rates measured, their brain activity assessed (electroencephalography), and were examined on their electrodermal responses. There was no notable difference between the probiotics and placebo groups after 8 weeks of intervention, according to the electroencephalography, electrodermal assessments, and heart rate monitors. However, the cognitive test reaction times significantly improved in the probiotic group, compared with the placebo group. These results suggest that probiotics supplementation may be capable of modulating brain waves in a way that enhances training, brain function, and psychological factors in competitive football players. [NPID: probiotics, brain function, athletes, athletic performance, sports, sports psychology, heart rate, brain waves, football players]

According to this 2019 article, probiotic supplements are being used by athletes to promote health and athletic performance. Noorifard et al. explains that intensive exercise on the professional level can increase production of free radicals and stress hormones, cause damage to body tissues, and reduce immune activity. This study investigated if probiotic supplementation could affect psychological health and the amount of oxidative stress enzymes in athletes. The 40 participants (swimmers) were split into two groups of 20. One group received one glass of probiotic juice every day for 12 weeks (this was the test group), while the other group received placebo juice for 12 weeks (the control group). After 12 weeks of this intervention, the level of antioxidants was significantly higher in the test group compared with the control group. In addition, the group receiving the probiotics showed better psychological parameters than the group taking the placebo drinks. In conclusion, the consumption of the probiotic juice positively influenced the athletes’ antioxidant system and mental health. [NPID: antioxidants, mental health, swimmers, athletes, probiotics, exercise, supplements, immunity]

This 2014 study was conducted to find out whether behavioral problems caused by high-fat diets such as anxiety and cognitive impairment can be exercised away, as suggested by certain studies. In this animal-model experiment, mice were examined under several conditions (fed a normal diet, normal diet with exercise, fed a high-fat diet, high-fat diet plus exercise). The mice given the high-fat diet had strong anxiety phenotypes, which were not affected by exercise. Although exercise increased the cognitive ability of the mice, the high-fat diet did not influence this. Since the gut microbiome is important in shaping the host state, the study also used rRNA tag sequencing to produce a gut microbiota profile for each mouse. The high-fat diet was found to significantly reshape the gut microbial community, supporting the findings of previous studies. Exercise alone influenced the gut microbiome to almost the same extent as diet but these changes were statistically independent. Therefore, aspects of behavior and the gut microbiome are both affected by diet and exercise but in unrelated ways. Furthermore, there was a correlation between specific bacterial abundances with measures of anxiety or cognition. This finding suggests that certain gut microbes can be used as biomarkers for anxiety or cognition, or even targeted for therapy. [NPID: gut microbiome, exercise, diet, anxiety, behavior, cognition, high-fat diet]

This 2016 study analyzed the amount and types of dietary supplements taken by American football players and measured their self-efficacies (their beliefs in their individual capacity to execute behaviors necessary on the football field). The objective was to assess the relationship between dietary supplement intake and self-efficacy in American football players. The 100 recruited athletes were aged between 20-30 years and Polish. A survey distributed online revealed that the most popular ergogenic supplements among these American football players were isotonic drinks, vitamin and mineral supplements, and protein concentrates. Around 74% of the athletes consumed isotonic drinks, whereas supplements like caffeine and/or guarana were consumed by 44% of the sample population. Other supplements such as BCAA amino acids (39%), creatine (36%), carbohydrate concentrates (30%) and omega-3 fatty acids (30%) had lower user percentage rates. The popularity of some dietary supplements varied depending on the general self-efficacy level of the athletes. The study concluded that sportsmen with lower levels of self-efficacy used multivitamin supplements significantly more often, compared with athletes reporting higher levels of self-efficacy. [NPID: athletes, athletic performance, self-efficacy, dietary supplements, supplementation, vitamins, isotonic drinks, amino acids, creatine, sports]

The aim of this 2018 study was to investigate whether adherence to the Mediterranean diet is connected to motivation in sport. Since habits can vary from nation to nation, this relationship was examined using university students from the 2 countries Romania and Spain. These students had an average age of around 21 and specialized in physical education. Using questionnaires and analysis indices, it was found that students from Spain had a high adherence to the Mediterranean diet and scored highly in task-oriented motivation. This task-oriented motivation trait was associated with low adherence to the Mediterranean diet in the Spanish students. Whereas participants from Romania showed higher scores in ego-oriented motivation, which showed correlations with medium adherence to the Mediterranean diet. This study reveals that Spanish university students may closely follow the Mediterranean diet. Moreover, these findings demonstrate that the motivation of performing better than other athletes may be related to greater adherence to the Mediterranean diet. [NPID: Mediterranean diet, healthy diets, athletes, physical exercise, athletic performance, motivation, motivational climate, university students]