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A Mismatch Between Athlete Practice and Current Sports Nutrition Guidelines Among Elite Female and Male Middle-and Long-Distance Athletes

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A Mismatch Between Athlete Practice and Current Sports Nutrition Guidelines Among Elite Female and Male Middle-and Long-Distance Athletes
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  351 ORIGINAL RESEARCH International Journal of Sport Nutrition and Exercise Metabolism,  2017, 27, 351 -360 https://doi.org/10.1123/ijsnem.2016-0316 © 2017 Human Kinetics, Inc. Heikura is with the Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, Austra-lia. Stellingwerff is with the Canadian Sport Institute Pacific, Victoria, Canada. Mero is with Biology of Physical Activity, University of Jyvaskyla, Finland. Uusitalo is with the Dept. of Clinical Physiology and Nuclear Medicine, HUS Medical Imaging Center, Helsinki, Helsinki University Central Hospital and University of Helsinki, Finland. Burke is with the Mary MacKillop Institute and Dept. of Sports Nutrition, Australian Institute of Sport, Canberra, Australia. Address author cor-respondence to Ida A. Heikura   at ida.heikura@myacu.edu.au. A Mismatch Between Athlete Practice and Current Sports Nutrition Guidelines Among Elite Female and Male Middle- and Long-Distance Athletes Ida A. Heikura, Trent Stellingwerff, Antti A. Mero, Arja Leena Tuulia Uusitalo, and Louise M. Burke 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 peri-odization 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 x 2  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 [  x  2  (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.  Keywords :   nutrient timing, recovery, elite athletes, carbohydrate availability, nutrition recommendationsAthletes organize their training into a periodized program, which integrates different types of workouts into various training cycles (e.g., micro, meso- and mac-rocycles, varying from days to weeks to months), with the goal of achieving optimal performance at targeted events. The athlete’s diet should be similarly periodized to recognize changing energy and macronutrient require-ments, particularly carbohydrate (CHO) and protein, to support the performance, recovery and adaptation goals of training (Thomas et al., 2016). Accordingly, guidelines for the optimal training diet have evolved from a universal prescription of a fairly static energy and macronutrient intake to the recognition that athletes need a personal-ized, periodized and practical plan (Thomas et al., 2016). Specific manipulation of the timing and amount of intake of energy and macronutrients from day to day, and week to week, has become known as “dietary periodization” or “nutrient timing” (Stellingwerff et al., 2007).Several evolving themes should be integrated into the periodized training and nutrition plan for endurance ath-letes. Energy availability, defined as the energy remaining to support the body’s health and function once the energy cost of exercise has been subtracted from energy intake, should be maintained at appropriate levels, even when manipulating body composition (Mountjoy et al., 2014). Second, CHO intake should be organized according to an assessment of CHO availability, defined as the capacity of body CHO stores to meet the fuel needs of, primarily, the muscle and brain around the training session (Burke et al., 2004). Current guidelines recognize the value of high CHO availability for key sessions which feature high-intensity performance, and/or practice of race conditions, where the quality of training is important (Burke et al., 2011). Conversely, high CHO availability may not be necessary for ”easy” or ”recovery” workouts;  352 Heikura et al. IJSNEM Vol. 27, No. 4, 2017  furthermore, there may be benefits to deliberately under-taking some of these sessions with low endogenous and/or exogenous CHO availability to increase metabolic stress and stimulate cellular adaptations (Hawley & Burke, 2010). Indeed, this so-called train low, or sleep low, has been shown to enhance mitochondrial biogenesis and the function and activity of associated enzymes and protein kinases, which makes this nutrition strategy a potential ergogenic aid in sports nutrition (Hawley & Burke, 2010). Regarding protein intake, there is now robust evidence that moderate amounts of high-quality protein sources should be spread over the day, including a postexercise snack following key training sessions, to optimize adapta-tion to the training stimulus (Phillips & Van Loon, 2011). While this new knowledge has been incorporated into current guidelines (Thomas et al. 2016), it is less certain that it has been adopted into practice by elite athletes.Therefore, our aim was to investigate dietary peri-odization strategies in elite endurance athletes, and to determine whether their eating practices result from careful planning and implementation of a specific nutri-tion strategy, or by coincidence. We accomplished this by developing a questionnaire covering the manipulation of energy, protein and CHO within, or between, training days to meet a number of different nutritional, practical or lifestyle goals. A second aim was to pilot test and further develop this questionnaire for use in a larger investigation into athlete practice versus current sports nutrition guidelines. Methods Study Design A questionnaire was emailed to 48 participants of a larger investigation on nutritional practices of elite endurance athletes, which included an investigation on actual dietary intakes and nutrient periodization around training ses-sions (Heikura et al. 2), comparison of energy availability, hormone concentrations and bone density (Heikura et al. 3) and an investigation on energy availability and hemo-globin mass changes during altitude training (Heikura et al. 4). The protocol was approved by the Ethics Commit-tee of the University of Jyväskylä and conformed to the Declaration of Helsinki. Participants Female and male Canadian, Australian and American world class middle- (females n  = 16, males n  = 13) and long-distance (females n  = 11, males n  = 4) runners and race walkers (males n  = 4) training in Flagstaff (AZ, USA) in Spring 2016 were recruited for the study. Inclu-sion criteria were 18–40 years of age, healthy, racing in middle-distance (800m–1500m and long-distance (3000m steeplechase–marathon, 20K–50K race-walk) events, and having scored ≥ 1050 IAAF points in a given event in the preceding two years (e.g., 1050 IAAF points for 5000m are 13:45.20 and 16:00.04 min for males and females, respectively.) Questionnaire The dietary periodization questionnaire was developed collaboratively by IAH, LMB and TS from a combined total of >50 years of experience and knowledge from working with elite athletes. It investigated between- and within-day dietary periodization and included multiple-choice and open answer formats, with six main themes (see Figure 1–6). Two themes considered whether athletes purposefully eat more (Theme 1; Figure 1) or fewer (Theme 2; Figure 2.) foods, or specific macronutrients, on hard or easy training days, respectively. Within-day questions considered timing of meals around pre- and post-key training sessions (Theme 3; Figure 3), training in the fasted state (Theme 4; Figure 4), practices of peri-odic CHO restriction (Theme 5; Figure 5), and training with high CHO availability (Theme 6; Figure 6). Further interrogation of these themes included a series of what, how, why type questions (see Figures). Athletes received the questionnaire after they had finished the diet/training record component of the project to ensure that its imple-mentation did not alter their usual behavior. Data Management and Statistical Analysis Two authors reviewed returned questionnaires by sys-tematically classifying answers into clusters for further analysis. The answers to each question were analyzed as total and group percentages (females vs males and middle- vs long-distance). Outcomes were displayed via the construction of decision-tree figures identifying the overall prevalence of responses. To investigate possible differences between subgroups, differences in responses >15% units were identified; these were tested for signifi-cance using Chi-square test (  X  2 ) for independence with Yates Continuity Correction (IBM SPSS Statistics version 22) along with the  phi  effect size statistic. Results Two males failed to return the questionnaire and were removed from the final analysis. Therefore, final data include 27 females (25.9 ± 3.2 yr, 1.68 ± 0.07 m, 53.9 ± 7.3 kg, IAAF score 1113 ± 37 points) and 19 males (27.7 ± 4.5 yr, 1.81 ± 0.06 m, 66.8 ± 658 kg, IAAF score 1114 ± 47 points). All questionnaires were of good quality and did not need further clarification from the athletes.Roughly one-third of females and males (37 vs 37%) as well as middle and long-distance (41 vs 32%) athletes reported eating more food on hard training days or the following day (Figure 1). Zero-% and 26% of long- vs middle-distance athletes reported eating more at main meals (  X  2  (1, n  = 46) = 5.49,  p  = .002,  phi  = 0.42), and 37% of females and 5% of males reported eating more    D  o  w  n   l  o  a   d  e   d   b  y   J  y  v  a  s   k  y   l  a  n   Y   l   i  o  p   i  s   t  o  o  n   0   7   /   2   3   /   1   7 ,   V  o   l  u  m  e   2   7 ,   A  r   t   i  c   l  e   N  u  m   b  e  r   4  A Dietary Periodization Questionnaire for Athletes 353 IJSNEM Vol. 27, No. 4, 2017 or the addition of questions, would elicit further or better information. These included the opportunity to comment on differences in practices across phases of the training/ competition year, interrogation of practices around body composition management, and further insights into the lack of utilization of various eating practices. Discussion This is a pilot study around the belief and practice of the within- and between-day periodization of energy and macronutrient intake by elite endurance athletes. Highly competitive middle- and long-distance athletes described, and gave their rationale for, alterations in nutrition strategies according to changes in their training load and the specific needs around key or easy training sessions, via a pilot questionnaire. Some common themes were increased energy intake on harder training days, and attention to the timing and content of meals pre- and post- key training sessions. Consuming CHO-rich meals to provide fuel for these sessions was practiced by most athletes, particularly long-distance athletes and females. Post-session intake of protein was the key focus of recovery. However, few athletes appeared to practice strategic use of training with low CHO or high CHO availability according to the goals of the session. Indeed, 24% undertook training in a fasted state and of those who reported this strategy a substantial number claimed practical reasons for its lack of implementation, rather than an intentional attempt to potentially enhance train-ing stimulus (Bartlett et al., 2015). Correspondingly, a minority (9%) of athletes specifically tried to manipulate diet to train with low glycogen concentrations (Bartlett et al., 2015). Reasons for failing to use these newer training-diet interventions included lack of belief, or experience, or that it interfered with training and general health, or a general lack of knowledge. Fewer than half of the ath-letes consumed CHO during workouts, with this strategy being mostly targeted to race practice by long-distance athletes as well as training support. This study suggests that most of these elite athletes seemed to follow the Figure 1 — Question 1, subquestions and answer choices regarding increases in food intake around increased training load. Symbols for females and males, and long- and middle-distance athletes are shown in the upper-left corner. Percentages (%) below each answer choice depict the % of all athletes that chose that specific answer choice. Where female/male, or long/middle-distance athlete symbols are present, these represent the % of athletes in these subgroups who chose the specific answer choice. The latter %-values are only shown when between-group difference was more than 15% units. * denotes a significant difference between females vs males, or middle vs long-distance athletes (  p  < .05). within 4h before training (  X  2  (1, n  = 46) = 4.57,  p  = .033,  phi  = 0.37). In contrast, 80% of athletes indicated that they do not intentionally eat less on easy training days (Figure 2; 22% females vs. 16% males; 15% middle-distance vs. 26% long-distance reported intentional food restriction).A significant majority of athletes (96 vs 100% of females vs males; 100% vs 95% middle vs long-distance) reported targeted nutrition practices before key training sessions (Figure 3). Recovery nutrition was the focus of 85% of females and 89% of males, as well as 93% of middle- and 79% of long-distance athletes (Figure 3).Training in a fasted state was reported by only 24% of the surveyed athletes (Figure 4), with 26% of females and 21% of males, and 11% of middle- vs 42% of long-distance athletes (  X  2  (1, n  = 46) = 4.308,  p  = .038,  phi  = 0.36) reporting this practice. Of those who did not report doing fasted training, 0% of females and 26% of males said they do not know why (  X  2  (1, n  = 46) = 5.49,  p  = .019,  phi  = 0.42). Eleven vs 5% of female and male athletes, respectively, and 15 vs 0% of middle- and long-distance athletes, respectively, reported intentional periodic restriction of CHO intake (Figure 5).Thirty percent of the athletes reported consuming CHO during workouts (Figure 6). Specifically, this prac-tice was present in 26% of females and 37% of males, and in 26% of middle- and 37% of long-distance athletes. Thirty-seven % vs 0% of long- vs middle-distance ath-letes reported doing this to practice race fueling (  X  2  (1, n  = 46) = 9.05,  p  = .003,  phi  = 0.51). While some differences in responses between subgroups were noted and merit further investigation, only a few were deemed significant.Reflection on the questionnaire identified a small number of issues in which rewording of the survey tool,    D  o  w  n   l  o  a   d  e   d   b  y   J  y  v  a  s   k  y   l  a  n   Y   l   i  o  p   i  s   t  o  o  n   0   7   /   2   3   /   1   7 ,   V  o   l  u  m  e   2   7 ,   A  r   t   i  c   l  e   N  u  m   b  e  r   4  354 Heikura et al. IJSNEM Vol. 27, No. 4, 2017 basic principles of sports nutrition, but there were some mismatches between athlete practice and current/evolving sports nutrition guidelines.Early sports nutrition guidelines provided a universal recommendation of a high CHO intake for all athletes and the achievement of high CHO availability around all training sessions (Coyle, 1991). Furthermore, initial messages around energy intake focused on general requirements to achieve energy balance, or alterations in energy balance to achieve changes in body composi-tion. However, contemporary guidelines have evolved to a more sophisticated appreciation of the dynamic nature of energy and macronutrient requirements across the periodized elements of training and competition, as well as the differentiation between diet-exercise strategies that support optimal performance and those that promote adaptation to an exercise stimulus (Thomas et al., 2016). We were interested to investigate how well these various contemporary concepts underpinning dietary periodiza-tion are being integrated into the training nutrition prac-tices of elite endurance athletes from Western countries. Daily Energy Availability Interest in the energy intakes of athletes now recognizes the issue of energy availability (EA) rather than energy balance alone. This concept considers the amount of energy which is available to support processes under-pinning health and function, by subtracting an athlete’s energy expenditure from exercise from total energy intake (Loucks et al., 2011). Low energy availability (LEA) can impair a range of activities that are important for Figure 2 — Question 2, subquestions and answer choices regarding decreased food intake around reduced training load. Symbols for females and males, and long- and middle-distance athletes are shown in the upper-left corner. Percentages (%) below each answer choice depict the % of all athletes that chose that specific answer choice. Where female/male, or long/middle-distance athlete symbols are present, these rep-resent the % of athletes in these subgroups who chose the specific answer choice. The latter %-values are only shown when between-group difference was more than 15% units.    D  o  w  n   l  o  a   d  e   d   b  y   J  y  v  a  s   k  y   l  a  n   Y   l   i  o  p   i  s   t  o  o  n   0   7   /   2   3   /   1   7 ,   V  o   l  u  m  e   2   7 ,   A  r   t   i  c   l  e   N  u  m   b  e  r   4  A Dietary Periodization Questionnaire for Athletes 355 IJSNEM Vol. 27, No. 4, 2017 an athlete’s health, ability to adapt optimally to train-ing, and performance itself in both females and males (Mountjoy et al., 2014). Athletes might reduce this risk by creating behaviors that allow daily energy intake to track with energy expenditure; for example, deliberately eating more in general on days of heavier training or by specifically adding nutrition support to pre, during, or post- hard training sessions. In the current study, 41% and 32% of middle- and long-distance athletes seemed aware of this concept, acknowledging an adjustment to energy intake around an increased training load. This was equally driven by hunger and an awareness of additional energy requirements (Figure 1). Different approaches to increase energy intake in terms of food choices and how they were added to the daily intake were reported. Adjust-ments to decrease energy intake around days of lighter training load were less frequently reported (Figure 2). Pre, During and Post-Key Session Nutrition Contemporary sports nutrition guidelines emphasize matching of CHO intake to the requirements of each training session and day, suggesting higher intakes on days or periods involving key training sessions (Burke et al., 2011; Thomas et al., 2016). Indeed, high CHO avail-ability, achieved by consuming CHO before/sessions to increase glycogen stores and/or intake of CHO during exercise, is recommended for maximized performance outcomes in sessions involving prolonged high intensity or high quality outputs (Burke et al., 2011; Stellingwerff et al., 2007; Stellingwerff & Cox, 2014). Consuming CHO during training sessions may also enhance gut tolerance and intestinal absorption capacity (Cox et al., 2010; Stellingwerff & Jeukendrup, 2011) as well as Figure 3 — Questions 3A and 3B, subquestions and answer choices regarding food intake before and after key training sessions. Symbols for females and males, and long- and middle-distance athletes are shown in the upper-left corner. Percentages (%) below each answer choice depict the % of all athletes that chose that specific answer choice. Where female/male, or long/middle-distance athlete symbols are present, these represent the % of athletes in these subgroups who chose the specific answer choice. The latter %-values are only shown when between-group difference was more than 15% units.    D  o  w  n   l  o  a   d  e   d   b  y   J  y  v  a  s   k  y   l  a  n   Y   l   i  o  p   i  s   t  o  o  n   0   7   /   2   3   /   1   7 ,   V  o   l  u  m  e   2   7 ,   A  r   t   i  c   l  e   N  u  m   b  e  r   4
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