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Kuikman MA, McKay AKA, Smith ES, Ackerman KE, Harris R, Elliott-Sale KJ, Stellingwerff T, Burke LM. Female Athlete Representation and Dietary Control Methods Among Studies Assessing Chronic Carbohydrate Approaches to Support Training. Int J Sport Nutr Exerc Metab 2023; 33:198-208. [PMID: 37160293 DOI: 10.1123/ijsnem.2022-0214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 02/15/2023] [Accepted: 03/26/2023] [Indexed: 05/11/2023]
Abstract
The aim of this audit was to assess the representation of female athletes, dietary control methods, and gold standard female methodology that underpins the current guidelines for chronic carbohydrate (CHO) intake strategies for athlete daily training diets. Using a standardized audit, 281 studies were identified that examined high versus moderate CHO, periodized CHO availability, and/or low CHO, high fat diets. There were 3,735 total participants across these studies with only ∼16% of participants being women. Few studies utilized a design that specifically considered females, with only 16 studies (∼6%) including a female-only cohort and six studies (∼2%) with a sex-based comparison in their statistical procedure, in comparison to the 217 studies (∼77%) including a male-only cohort. Most studies (∼72%) did not provide sufficient information to define the menstrual status of participants, and of the 18 studies that did, optimal methodology for control of ovarian hormones was only noted in one study. While ∼40% of male-only studies provided all food and beverages to participants, only ∼20% of studies with a female-specific design used this approach for dietary control. Most studies did not implement strategies to ensure compliance to dietary interventions and/or control energy intake during dietary interventions. The literature that has contributed to the current guidelines for daily CHO intake is lacking in research that is specific to, or adequately addresses, the female athlete. Redressing this imbalance is of high priority to ensure that the female athlete receives evidence-based recommendations that consider her specific needs.
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Affiliation(s)
- Megan A Kuikman
- Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, VIC,Australia
| | - Alannah K A McKay
- Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, VIC,Australia
| | - Ella S Smith
- Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, VIC,Australia
| | - Kathryn E Ackerman
- Female Athlete Program, Boston Children's Hospital and Harvard Medical School, Boston, MA,USA
| | - Rachel Harris
- Female Performance and Health Initiative, Australian Institute of Sport, Canberra, ACT,Australia
- Perth Orthopaedic and Sports Medicine Research Institute, West Perth, WA,Australia
| | - Kirsty J Elliott-Sale
- Department of Sport and Exercise Sciences, Institute of Sport, Manchester Metropolitan University, Manchester,United Kingdom
| | - Trent Stellingwerff
- Canadian Sport Institute-Pacific, Institute for Sport Excellence, Victoria, BC,Canada
- Exercise Science, Physical and Health Education, University of Victoria, Victoria, BC,Canada
| | - Louise M Burke
- Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, VIC,Australia
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Bowler AM, Whitfield J, Marshall L, Coffey VG, Burke LM, Cox GR. The Use of Continuous Glucose Monitors in Sport: Possible Applications and Considerations. Int J Sport Nutr Exerc Metab 2023; 33:121-32. [PMID: 36572039 DOI: 10.1123/ijsnem.2022-0139] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 11/03/2022] [Accepted: 11/14/2022] [Indexed: 12/28/2022]
Abstract
This review discusses the potential value of tracking interstitial glucose with continuous glucose monitors (CGMs) in athletes, highlighting possible applications and important considerations in the collection and interpretation of interstitial glucose data. CGMs are sensors that provide real time, longitudinal tracking of interstitial glucose with a range of commercial monitors currently available. Recent advancements in CGM technology have led to the development of athlete-specific devices targeting glucose monitoring in sport. Although largely untested, the capacity of CGMs to capture the duration, magnitude, and frequency of interstitial glucose fluctuations every 1-15 min may present a unique opportunity to monitor fueling adequacy around competitive events and training sessions, with applications for applied research and sports nutrition practice. Indeed, manufacturers of athlete-specific devices market these products as a "fueling gauge," enabling athletes to "push their limits longer and get bigger gains." However, as glucose homeostasis is a complex phenomenon, extensive research is required to ascertain whether systemic glucose availability (estimated by CGM-derived interstitial glucose) has any meaning in relation to the intended purposes in sport. Whether CGMs will provide reliable and accurate information and enhance sports nutrition knowledge and practice is currently untested. Caveats around the use of CGMs include technical issues (dislodging of sensors during periods of surveillance, loss of data due to synchronization issues), practical issues (potential bans on their use in some sporting scenarios, expense), and challenges to the underpinning principles of data interpretation, which highlight the role of sports nutrition professionals to provide context and interpretation.
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Johnson-Bonson DA, Narang BJ, Davies RG, Hengist A, Smith HA, Watkins JD, Taylor H, Walhin JP, Gonzalez JT, Betts JA. Interactive effects of acute exercise and carbohydrate-energy replacement on insulin sensitivity in healthy adults. Appl Physiol Nutr Metab 2021; 46:1207-1215. [PMID: 33831317 DOI: 10.1139/apnm-2020-1043] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This study investigated whether carbohydrate-energy replacement immediately after prolonged endurance exercise attenuates insulin sensitivity the following morning, and whether exercise improves insulin sensitivity the following morning independent of an exercise-induced carbohydrate deficit. Oral glucose tolerance and whole-body insulin sensitivity were compared the morning after 3 evening conditions, involving (1) treadmill exercise followed by a carbohydrate replacement drink (200 or 150 g maltodextrin for males and females, respectively; CHO-replace); (2) treadmill exercise followed by a non-caloric, taste-matched placebo (CHO-deficit); or (3) seated rest with no drink provided (Rest). Treadmill exercise involved 90 minutes at ∼80% age-predicted maximum heart rate. Seven males and 2 females (aged 23 ± 1 years; body mass index 24.0 ± 2.7 kg·m-2) completed all conditions in a randomised order. Matsuda index improved by 22% (2.2 [0.3, 4.0] au, p = 0.03) and HOMA2-IR improved by 10% (-0.04 [-0.08, 0.00] au, p = 0.04) in CHO-deficit versus CHO-replace, without corresponding changes in postprandial glycaemia. Outcomes were similar between Rest and other conditions. These data suggest that improvements to insulin sensitivity in healthy populations following acute moderate/vigorous intensity endurance exercise may be dependent on the presence of a carbohydrate-energy deficit. Novelty: Restoration of carbohydrate balance following acute endurance exercise attenuated whole-body insulin sensitivity. Exercise per se failed to enhance whole-body insulin sensitivity. Maximising or prolonging the post-exercise carbohydrate deficit may enhance acute benefits to insulin sensitivity.
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Affiliation(s)
- Drusus A Johnson-Bonson
- Centre for Nutrition, Exercise & Metabolism, Department for Health, University of Bath, Bath, Somerset, United Kingdom.,School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, Leicestershire, United Kingdom
| | - Benjamin J Narang
- Centre for Nutrition, Exercise & Metabolism, Department for Health, University of Bath, Bath, Somerset, United Kingdom.,Department of Automation, Biocybernetics, and Robotics, Institut Jožef Stefan, Ljubljana, Slovenia.,Faculty of Sport, University of Ljubljana, Ljubljana, Slovenia
| | - Russell G Davies
- Centre for Nutrition, Exercise & Metabolism, Department for Health, University of Bath, Bath, Somerset, United Kingdom
| | - Aaron Hengist
- Centre for Nutrition, Exercise & Metabolism, Department for Health, University of Bath, Bath, Somerset, United Kingdom
| | - Harry A Smith
- Centre for Nutrition, Exercise & Metabolism, Department for Health, University of Bath, Bath, Somerset, United Kingdom
| | - Jonathan D Watkins
- Centre for Nutrition, Exercise & Metabolism, Department for Health, University of Bath, Bath, Somerset, United Kingdom
| | - Harry Taylor
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, Merseyside, United Kingdom
| | - Jean-Philippe Walhin
- Centre for Nutrition, Exercise & Metabolism, Department for Health, University of Bath, Bath, Somerset, United Kingdom
| | - Javier T Gonzalez
- Centre for Nutrition, Exercise & Metabolism, Department for Health, University of Bath, Bath, Somerset, United Kingdom
| | - James A Betts
- Centre for Nutrition, Exercise & Metabolism, Department for Health, University of Bath, Bath, Somerset, United Kingdom
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Heikura IA, Stellingwerff T, Burke LM. Self-Reported Periodization of Nutrition in Elite Female and Male Runners and Race Walkers. Front Physiol 2018; 9:1732. [PMID: 30559680 PMCID: PMC6286987 DOI: 10.3389/fphys.2018.01732] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Accepted: 11/16/2018] [Indexed: 12/29/2022] Open
Abstract
Athletes should achieve event-specific physiological requirements through careful periodization of training, underpinned by individualized and targeted nutrition strategies. However, evidence of whether, and how, elite endurance athletes periodize nutrition is scarce. Accordingly, elite international female (n = 67) and male (n = 37) middle/long-distance athletes (IAAF score: 1129 ± 54, corresponds to 13:22.49 [males] and 15:17.93 [females] in the 5000 m) completed an online survey (February-May 2018) examining self-reported practices of dietary periodization for micro (within/between-days), meso (weeks/months) and macro (across the year) contexts. Data are shown as the percentage of all athletes practicing a given strategy followed by the % of athletes reporting various beliefs or practices within this strategy. Differences according to sex, event (middle-distance [800 m/1500 m] vs. track-distance [3000 m-10000 m] vs. road-distance [marathon/race walks]), caliber (high [major championship qualifier] vs. lower), and training volume (low/moderate/high male and female tertiles) were analyzed using Chi-square test or Kruskal-Wallis Test and indicated statistically different when p ≤ 0.05. Most athletes reported eating more on hard training days (92%) and focusing on nutrition before (84%; carbohydrate intake [63%] and timing [58%]) and after (95%; protein goals [59%], timing [55%], carbohydrate goals [50%]) key sessions. Road-distance were the most (62 and 57%), and middle-distance the least (30 and 30%) likely to train fasted (p = 0.037) or restrict carbohydrates periodically (p = 0.050), respectively. Carbohydrate intake during training (58% of total) was more common in males (79%; p = 0.004) and road-distance (90%; p < 0.001) than females (53%) or middle/track-distance (48 and 37%). Most athletes (83%) reported following a specific diet before and during race day, with half of the athletes focusing on carbohydrates. Nearly all (97%) road-distance athletes reported following a during-race nutrition plan (carbohydrates/fluids:89%). Only 32% reported taking advice from a dietitian/nutritionist. Based on our analysis: (1) Road-distance athletes periodize carbohydrate availability while track/middle-distance avoid low carbohydrate availability; (2) Middle-distance runners emphasize physique goals to guide their nutrition strategies; (3) Females seem to be more cautious of increasing energy/carbohydrate intake; (4) Among all athletes, nutrition strategies are chosen primarily to improve performance, followed by reasons related to physique, adaptation and health outcomes. Overall, these athletes appear to possess good knowledge of nutrition for supporting training and competition performance.
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Affiliation(s)
- Ida Aliisa Heikura
- Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, VIC, Australia
- Sports Nutrition, Australian Institute of Sport, Canberra, ACT, Australia
| | | | - Louise Mary Burke
- Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, VIC, Australia
- Sports Nutrition, Australian Institute of Sport, Canberra, ACT, Australia
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McKay AKA, Pyne DB, Peeling P, Sharma AP, Ross MLR, Burke LM. The impact of chronic carbohydrate manipulation on mucosal immunity in elite endurance athletes. J Sports Sci 2018; 37:553-559. [PMID: 30207506 DOI: 10.1080/02640414.2018.1521712] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Carbohydrate (CHO) availability could alter mucosal immune responses to exercise. This study compared the effect of three dietary approaches to CHO availability on resting and post-exercise s-IgA levels. Elite race walkers (n = 26) adhered to a high CHO diet (HCHO), periodised CHO availability (PCHO) or a low CHO/high fat diet (LCHF) for 3 weeks while completing an intensified training program. HCHO and PCHO groups consumed 8.0-8.5 g.kg-1 CHO daily, with timing of ingestion manipulated to alter CHO availability around key training sessions. The LCHF diet comprised 80% fat and restricted CHO to < 50 g.day-1. A race walk test protocol (19 km females, 25 km males) was completed at baseline, after adaptation, and following CHO restoration. On each occasion, saliva samples were obtained pre- and post-exercise to quantify s-IgA levels. Resting s-IgA secretion rate substantially increased ~ two-fold post-intervention in all groups (HCHO: 2.2 ± 2.2, PCHO: 2.8 ± 3.2, LCHF: 1.6 ± 1.6; fold-change± 95% confidence limits), however, no substantial differences between dietary treatments were evident. Post-exercise, substantial 20-130% increases in s-IgA concentration and 43-64% reductions in flow rate occurred in all dietary treatments, with trivial differences evident between groups. It appears that high volume training overrides any effect of manipulating CHO availability on mucosal immunity in elite athletes.
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Affiliation(s)
- Alannah K A McKay
- a School of Human Sciences (Exercise and Sport Science) , The University of Western Australia , Crawley , Australia.,b Australian Institute of Sport , ACT , Bruce , Australia.,c Western Australian Institute of Sport , Mt Claremont , Australia
| | - David B Pyne
- b Australian Institute of Sport , ACT , Bruce , Australia.,d Research Institute for Sport and Exercise , University of Canberra , Canberra , Australia
| | - Peter Peeling
- a School of Human Sciences (Exercise and Sport Science) , The University of Western Australia , Crawley , Australia.,c Western Australian Institute of Sport , Mt Claremont , Australia
| | - Avish P Sharma
- b Australian Institute of Sport , ACT , Bruce , Australia.,d Research Institute for Sport and Exercise , University of Canberra , Canberra , Australia
| | - Megan L R Ross
- b Australian Institute of Sport , ACT , Bruce , Australia.,e Mary MacKillop Institute for Health Research , Australian Catholic University , Melbourne , Australia
| | - Louise M Burke
- b Australian Institute of Sport , ACT , Bruce , Australia.,e Mary MacKillop Institute for Health Research , Australian Catholic University , Melbourne , Australia
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Abstract
The application of molecular techniques to exercise biology has provided novel insight into the complexity and breadth of intracellular signaling networks involved in response to endurance-based exercise. Here we discuss several strategies that have high uptake by athletes and, on mechanistic grounds, have the potential to promote cellular adaptation to endurance training in skeletal muscle. Such approaches are based on the underlying premise that imposing a greater metabolic load and provoking extreme perturbations in cellular homeostasis will augment acute exercise responses that, when repeated over months and years, will amplify training adaptation.
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Affiliation(s)
- John A Hawley
- Exercise and Nutrition Research Program, Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, VIC 3000, Australia.
| | - Carsten Lundby
- Centre for Physical Activity Research, Copenhagen University Hospital, Copenhagen, Denmark
| | - James D Cotter
- School of Physical Education, Sport and Exercise Sciences, University of Otago, Dunedin, New Zealand
| | - Louise M Burke
- Exercise and Nutrition Research Program, Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, VIC 3000, Australia; Department of Sport Nutrition, Australian Institute of Sport, Belconnen, ACT, Australia
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Heikura IA, Stellingwerff T, Mero AA, Uusitalo ALT, Burke LM. A Mismatch Between Athlete Practice and Current Sports Nutrition Guidelines Among Elite Female and Male Middle- and Long-Distance Athletes. Int J Sport Nutr Exerc Metab 2017; 27:351-60. [PMID: 28338358 DOI: 10.1123/ijsnem.2016-0316] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Contemporary nutrition guidelines promote a variety of periodized and time-sensitive recommendations, but current information regarding the knowledge and practice of these strategies among world-class athletes is limited. The aim of this study was to investigate this theme by implementing a questionnaire on dietary periodization practices in national/international level female (n = 27) and male (n = 21) middle- and long-distance runners/race-walkers. The questionnaire aimed to gain information on between and within-day dietary choices, as well as timing of pre- and posttraining meals and practices of training with low or high carbohydrate (CHO) availability. Data are shown as percentage (%) of all athletes, with differences in responses between subgroups (sex or event) shown as Chi-square x2 when p < .05. Nearly two-thirds of all athletes reported that they aim to eat more food on, or after, hard training days. Most athletes said they focus on adequate fueling (96%) and adequate CHO and protein (PRO) recovery (87%) around key sessions. Twenty-six percent of athletes (11% of middle vs 42% of long-distance athletes [x2 (1, n = 46) = 4.308, p = .038, phi = 0.3])) reported to undertake training in the fasted state, while 11% said they periodically restrict CHO intake, with 30% ingesting CHO during training sessions. Our findings show that elite endurance athletes appear to execute pre- and post-key session nutrition recovery recommendations. However, very few athletes deliberately undertake some contemporary dietary periodization approaches, such as training in the fasted state or periodically restricting CHO intake. This study suggests mismatches between athlete practice and current and developing sports nutrition guidelines.
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