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Background: Time-restricted feeding (TRF), a form of intermittent fasting, limits daily caloric intake to a 6-12 hour window and has been shown to effectively promote weight loss and improve overall health. This systematic review and meta-analysis aimed to compare the effects of TRF versus normal diet (ND) on physical performance and body composition in healthy adults with regular exercise habits. Methods: MEDLINE, PubMed, Embase, SPORTDiscus, Web of Science, CINAHL and the Cochrane Central Register of Controlled Trials (CENTRAL) electronic databases were searched for relevant records. Subgroup analyses were conducted based on the duration of intervention and type of exercise. Physical performance was analysed using standardised mean differences (SMDs) and 95% CIs, whereas body composition parameters were analysed using mean differences (MDs) and 95% CIs. The quality of the included studies was examined using the Cochrane risk-of-bias tool version 2. Results: 15 randomised controlled trials with 361 participants were included in the systematic review. In comparison with the ND group, TRF significantly decreased body weight (MD=-1.76 kg, 95% CI -3.40 to -0.13, p=0.03, I2=11.0%) and fat mass (MD=-1.24 kg, 95% CI -1.87 to -0.61, p<0.001, I2=0.0%). No between-group differences in physical performance-related variables and fat-free mass were found. According to the result of the risk-of-bias assessment, one study showed a low risk of bias, 13 showed some concerns, and one showed a high risk of bias. Conclusion: TRF may be a valuable nutritional strategy to optimise body composition and maintain physical performance in healthy adults engaged in regular exercise. PROSPERO registration number: CRD42022310140.

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Objectives: This cross-sectional study aimed to describe dietary habits in Swedish adolescent handball players and differences with respect to sex and school grade. Methods: Participants in the Swedish Handball Cohort answered a web-survey assessing adherence to sports nutrition recommendations for meal frequency and meal timing, and the Nordic Nutrition Recommendations (NNR) for fruits/vegetables and fish/seafood, food exclusions and use of dietary supplements. Differences with respect to sex and school grade were estimated with generalised linear models, generating prevalence ratios (PR) with 95% CIs. Results: A total of 1040 participants (16.6±0.9 years, 51% males) were included. Overall, 70% and 90%, respectively, met recommendations for meal frequency and meal timing, whereas adherence to recommended carbohydrate intake during training/game was met by 17%. Adherence to the NNR for fruits/vegetables and fish/seafood was met by 16% and 37%, respectively. Twenty-eight per cent reported using dietary supplements. Females reported lower frequency of meals, especially morning snacks (-0.6 days/week (95% CI -0.3 to -0.9)) and evening snacks (-0.8 days/week (95% CI -0.5 to -1.1)), higher prevalence of exclusions due to intolerances (PR 1.66 (95% CI 1.31 to 2.01)) and other reasons (PR 1.36 (95% CI 1.08 to 1.64)), higher adherence to the NNR for fruits/vegetables (PR 2.30 (95% CI 1.98 to 2.62)) and use of micronutrient supplements (PR 1.72 (95% CI 1.43 to 2.00)) compared with males. Only small differences were observed between school grades. Conclusions: Swedish adolescent handball players' dietary habits are fairly in accordance with sports nutrition recommendations but not the NNR. Females appear to display more restrictive habits than males.

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Objectives: This retrospective, cross-sectional study aimed to investigate symptoms of eating disorders (EDs) and low energy availability (LEA) among recreational female runners. Methods: Females (18-39 years) (n=89) participating in running group sessions organised by running clubs and companies were recruited via social media and completed an anonymous online survey compromising the Eating Disorder Examination Questionnaire (EDE-Q) and Low Energy Availability in Females Questionnaire (LEAF-Q). An EDE-Q global score ≥2.3 and a LEAF-Q total score ≥8 (in combination with an injury score≥2 and/or menstruation dysfunction score≥4) were used to categorise subjects as having symptoms of EDs and LEA, respectively. Results: Among the subjects fulfilling the age criteria (n=85), 18% (n=15) had symptoms of EDs and 19% (n=16) had symptoms of LEA. Of those with symptoms of EDs, 13% (n=2) had concomitant symptoms of LEA. The higher the EDE-Q dietary restraint score, the higher the gastrointestinal problem score (r=0.23, p=0.04), otherwise no other associations were found between EDE-Q global or subscale scores and LEAF-Q scores. Conclusion: Our results indicate that symptoms of EDs and LEA are frequent among adult females at all athletic levels, including the recreational level. Hence, to prevent the negative health consequences of EDs and LEA, preventative initiatives are also needed in recreational running communities.

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Enduring low energy availability (LEA) is associated with several potentially serious physiological and mental conditions. LEA has been found highly prevalent among female elite athletes within endurance sports, thus hampering athletes' health and performance. The prevalence and the underpinning risk factors of LEA among female elite football players are less studied. One reason is that the existing self-report measures and technological devices to monitor energy intake and expenditure are inadequately adapted to capture the nature of the physical activity and energy expenditure among football players and are thus inaccurate. The present paper outlines a study protocol addressing the prevalence of LEA, the measurement of LEA and the correlations of LEA in terms of health and performance in female football players. Four studies will be conducted with the following aims (1) to evaluate the accuracy of global positioning systems (GPS)-based devices to monitor energy expenditure with indirect calorimetry as the gold standard, (2) to assess energy intake, quantify energy expenditure and investigate energy availability through self-report instruments, double labelled water (DLW) and GPS monitoring devices, (3) to determine the point prevalence of LEA using self-report instruments, DLW, dual-X-ray-absorptiometry (DXA) to quantify muscle and bone mass distribution and density, and a battery of hormonal analyses, and (4) to explore whether the prevalence of LEA varies across a full football season. Measures covering mental symptoms and psychological resources will be included, and a selection of biological measures derived from study 3. Measurements of DXA and DLW are resource-demanding and will be collected from one professional club (N~20 women). In contrast, the remaining data will be collected from four professional clubs (N~60 women) located in Bergen, the largest city within the Western region of Norway. Overall procedures and biobank storage procedures have been approved for data collection that will end in December 2024.

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OBJECTIVE: To determinate the prevalence of EDs in national adult male team sports players. METHODOLOGY: An observational study was conducted with 124 football, rugby, volleyball, handball, water polo, baseball and hockey players ranging between 18 and 55 years old. All subjects signed the informed consent before participating in the study. Data were collected via an online form including four validated questionnaires: The Eating Habits Questionnaire for Athletes, the Eating Attitudes Test (EAT-40), the Eating Disorders Inventory-2 and the Body Shape Questionnaire. Data analysis was conducted with the software IBM SPSS V.23.0.0. RESULTS: 18.5% of the population presented a clinical profile compatible with an ED diagnosis. We cannot confidently say that the prevalence of EDs within our sample is conditioned by the analysed variables. CONCLUSION: Male team sports players may also be a high-risk group in the development of EDs. Risk factors such as young age, semiprofessional sporting status and body fat composition could influence its development.

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Nutrition is an undeniable part of promoting health and performance among football (soccer) players. Nevertheless, nutritional strategies adopted in elite football can vary significantly depending on culture, habit and practical constraints and might not always be supported by scientific evidence. Therefore, a group of 28 Portuguese experts on sports nutrition, sports science and sports medicine sought to discuss current practices in the elite football landscape and review the existing evidence on nutritional strategies to be applied when supporting football players. Starting from understanding football's physical and physiological demands, five different moments were identified: preparing to play, match-day, recovery after matches, between matches and during injury or rehabilitation periods. When applicable, specificities of nutritional support to young athletes and female players were also addressed. The result is a set of practical recommendations that gathered consensus among involved experts, highlighting carbohydrates periodisation, hydration and conscious use of dietary supplements.

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OBJECTIVES: To investigate indicators and correlates of low energy availability (LEA) in male and female dancers. METHODS: A Dance-Specific Energy Availability Questionnaire (DEAQ) was developed and administered online internationally to dancers training at preprofessional, professional or advanced amateur level. The DEAQ drew on current validated, published questionnaires for LEA, linked to the clinical outcomes of relative energy deficiency in sport (RED-S). Questions addressed recognised physiological indicators and consequences of LEA in the context of dance, together with potential correlates. LEA was quantified using a scoring system to include these characteristics. RESULTS: 247 responses to the DEAQ were analysed (225 female and 22 male), mean age 20.7 years (SD 7.9) with 85% practising ballet. Psychological, physiological and physical characteristics consistent with LEA were reported by 57% of the female dancers and 29% of male dancers, indicating a risk of RED-S. The unique nature of dance training, in terms of demands and environment, was found to be potentially influential in development of this situation. Less than one-third (29%) of dancers were aware of RED-S. CONCLUSION: This study found dancers to be a specific group of high-level artistic performers displaying indicators of LEA and consequently at risk of developing the adverse clinical health and performance consequences of RED-S. Awareness of RED-S was low. The DEAQ has the potential to raise awareness and be a practical, objective screening tool to identify dancers in LEA, at risk of developing RED-S.

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OBJECTIVE: The impact of phosphorus supplementation on athletic performance is unclear. Ingestion of phosphorus for several days has been reported to increase cardiac capacity, improve oxygen muscle kinetics and enhance lactate buffering capacity. Recent studies have shown that phosphorus ingestion with a meal increases postprandial glucose uptake and thermogenesis. The present study aimed to assess the effect of acute phosphorus ingestion with a meal on specific workload parameters. METHODS: A double-blind, crossover trial of 12 male water polo players between 18 and 22 years old was conducted. Overnight fasted subjects were asked to cycle for 20 min before ingesting 100 g of glucose with phosphorus or placebo (400 mg). Three hours later, they were asked to perform a graded cycling exercise for 25 min. RESULTS: Expenditure, respiratory quotient, perception of fatigue and exercise efficiency were similar between treatments. However, heart rate was significantly higher in the phosphorus group (142±10 beats/min) compared with placebo (135±10 beats/min). CONCLUSION: Exercise performance 3 hours after the coingestion of glucose with phosphorus did not affect substrate use, while heart rate was increased. The heart rate increase could be attributed to a rise in core body temperature. TRIAL REGISTRATION NUMBER: NCT03101215.

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The majority of lightweight rowers undertake acute weight loss prior to competition. Given the competitive advantage afforded to larger, more muscular rowers over their smaller counterparts, the use of moderate, acute weight loss may be justified, at least among larger, leaner athletes who struggle to achieve the specified body mass requirement and have limited potential for further body mass loss via reductions in body fat. The performance implications of moderate acute weight loss appear to be small on the ergometer and may be even less on water, at least when aggressive recovery strategies are adopted between weigh-in and racing. Furthermore, any performance implications of acute weight loss are not exacerbated when such weight loss is undertaken repeatedly throughout the course of a regatta, and may even be eliminated when aggressive recovery strategies are introduced before and after racing. The combination of adequate sodium, fluid and carbohydrate in line with current guidelines results in the best performances. While the performance implications of modest acute weight loss may still need to be considered in regard to competition outcome, chronic body mass strategies may not be without performance implications. This is especially the case for athletes who have very low levels of body fat and/or athletes who decrease their body mass too quickly. Further studies are needed to address the degree of weight loss that can be tolerated with minimal health and/or performance implications, and the optimal time frame over which this should occur. Possible adaptation to the physiological state that accompanies acute weight loss also warrants investigation.

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BACKGROUND: Successful performers in weight-sensitive sports are characterised by low body mass (BM) and fat content. This often requires chronic energy restriction and acute weight loss practices. AIM: To evaluate current use of body composition (BC) assessment methods and identify problems and solutions with current BC approaches. METHODS: A 40-item survey was developed, including demographic and content questions related to BC assessment. The survey was electronically distributed among international sporting organisations. Frequencies and χ(2) analyses were computed. RESULTS: 216 responses were received, from 33 countries, representing various institutions, sports and competitive levels. Of the sample, 86% of respondents currently assess BC, most frequently using skinfolds (International Society for the Advancement of Kinanthropometry (ISAK): 50%; non-ISAK, conventional: 40%; both: 28%), dual energy X-ray absorptiometry (38%), bioelectrical impedance (29%), air displacement plethysmography (17%) and hydrostatic weighing (10%). Of those using skinfolds, more at the international level used ISAK, whereas conventional approaches were more reported at regional/national level (p=0.006). The sport dietitian/nutritionist (57%) and physiologist/sports scientist (54%) were most frequently the professionals assessing BC, followed by MDs and athletic trainers, with some reporting coaches (5%). 36% of 116 respondents assessed hydration status and more (64%) did so at international than regional/national level (36%, p=0.028). Of 125 participants answering the question of whether they thought that BC assessment raised problems, 69% said 'yes', with most providing ideas for solutions. CONCLUSIONS: Results show high use of BC assessment but also a lack of standardisation and widespread perception of problems related to BM and BC in sport. Future work should emphasise standardisation with appropriate training opportunities and more research on BC and performance.

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BACKGROUND: Studies failing to show a negative effect of rapid weight loss (RWL) on performance have been conducted in athletes who have been cycling weight for years. It has been suggested that chronic weight cycling could lead combat athletes to become resistant to the stresses associated with weight loss. To investigate the effects of RWL up to 5% of body mass on high-intensity intermittent performance in weight cyclers (WC) and non-weight cyclers (non-WC). METHODS: Eighteen male combat athletes (WC: n=10; non-WC: n=8) reduced up to 5% of their body mass in 5 days. Body composition, high-intensity performance and plasma lactate were assessed preweight loss and postweight loss. Athletes had 4 h to re-feed and rehydrate following the weigh-in. Food intake was recorded during the weight loss and the recovery periods. RESULTS: Athletes significantly decreased body mass, lean body mass (most likely due to fluid loss) and fat mass following weight loss. No significant changes in performance were found from preweight loss to postweight loss in both groups. Plasma lactate was significantly elevated after exercise in both groups, but no differences were found between groups and in response to RWL. For all these variables no differences were observed between groups. Athletes from both groups ingested high amounts of energy and carbohydrates during the recovery period after the weigh-in. CONCLUSIONS: Chronic weight cycling does not protect athletes from the negative impact of RWL on performance. The time to recover after weigh-in and the patterns of food and fluid ingestion during this period is likely to play the major role in restoring performance to baseline levels.

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BACKGROUND: Vitamin D deficiency is common in the general public and athletic populations and may impair skeletal muscle function. We therefore assessed the effects of vitamin D3 supplementation on serum 25[OH]D concentrations and physical performance. METHODS: 30 club-level athletes were block randomised (using baseline 25[OH]D concentrations) into one of three groups receiving either a placebo (PLB), 20 000 or 40 000 IU/week oral vitamin D3 for 12 weeks. Serum 25[OH]D and muscle function (1-RM bench press and leg press and vertical jump height) were measured presupplementation, 6 and 12 weeks postsupplementation. Vitamin D deficiency was defined in accordance with the US Institute of Medicine guideline (<50 nmol/l). RESULTS: 57% of the subject population were vitamin D deficient at baseline (mean±SD value 51±24 nmol/l). Following 6 and 12 weeks supplementation with 20 000 IU (79±14 and 85±10 nmol/l, respectively) or 40 000 IU vitamin D3 (98±14 and 91±24 nmol/l, respectively), serum vitamin D concentrations increased in all participants, with every individual achieving concentrations greater than 50 nmol/l. In contrast, vitamin D concentration in the PLB group decreased at 6 and 12 weeks (37±18 and 41±22 nmol/l, respectively). Increasing serum 25[OH]D had no significant effect on any physical performance parameter (p>0.05). CONCLUSIONS: Both 20 000 and 40 000 IU vitamin D3 supplementation over a 6-week period elevates serum 25[OH]D concentrations above 50 nmol/l, but neither dose given for 12 weeks improved our chosen measures of physical performance.

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