In elite sport, where opponents are evenly matched, small factors can determine the outcome of sporting contests. Not all athletes know the value of making wise nutrition choices, but anything that might give a competitive edge, including dietary supplements, can seem attractive. Between 40% and 100% of athletes typically use supplements, depending on the type of sport, level of competition, and the definition of supplements. However, unless the athlete has a nutrient deficiency, supplementation may not improve performance and may have a detrimental effect on both performance and health. Dietary supplements are classified as a subcategory of food, so manufacturers are not required to provide evidence of product safety and efficacy, nor obtain approval from regulatory bodies before marketing supplements. This creates the potential for health risks, and serious adverse effects have been reported from the use of some dietary supplements. Athletes who compete in sports under an anti-doping code must also realize that supplement use exposes them to a risk of ingesting banned substances or precursors of prohibited substances. Government systems of regulations do not include specific laboratory testing for banned substances according to the WADA list, so a separate regulatory framework to evaluate supplements for their risk of provoking a failed doping test is needed. In the high-performance culture typical of elite sport, athletes may use supplements regardless of possible risks. A discussion around medical, physiological, cultural, and ethical questions may be warranted to ensure that the athlete has the information needed to make an informed choice.
Ina Garthe and Ronald J. Maughan
Ina Garthe, Truls Raastad and Jorunn Sundgot-Borgen
When weight loss (WL) is needed, it is recommended that athletes do it gradually by 0.5–1 kg/wk through moderate energy restriction. However, the effect of WL rate on long-term changes in body composition (BC) and performance has not been investigated in elite athletes.
To compare changes in body mass (BM), fat mass (FM), lean body mass (LBM), and performance 6 and 12 mo after 2 different WL interventions promoting loss of 0.7% vs. 1.4% of body weight per wk in elite athletes.
Twenty-three athletes completed 6- and 12-mo postintervention testing (slow rate [SR] n = 14, 23.5 ± 3.3 yr, 72.2 ± 12.2 kg; fast rate [FR] n = 9, 21.4 ± 4.0 yr, 71.6 ± 12.0 kg). The athletes had individualized diet plans promoting the predetermined weekly WL during intervention, and 4 strength-training sessions per wk were included. BM, BC, and strength (1-repetition maximum) were tested at baseline, postintervention, and 6 and 12 mo after the intervention.
BM decreased by ~6% in both groups during the intervention but was not different from baseline values after 12 mo. FM decreased in SR and FR during the intervention by 31% ± 3% vs. 23% ± 4%, respectively, but was not different from baseline after 12 mo. LBM and upper body strength increased more in SR than in FR (2.0% ± 1.3% vs. 0.8% ± 1.1% and 12% ± 2% vs. 6% ± 2%) during the intervention, but after 12 mo there were no significant differences between groups in BC or performance.
There were no significant differences between groups after 12 mo, suggesting that WL rate is not the most important factor in maintaining BC and performance after WL in elite athletes.
Oliver C. Witard, Ina Garthe and Stuart M. Phillips
Track and field athletes engage in vigorous training that places stress on physiological systems requiring nutritional support for optimal recovery. Of paramount importance when optimizing recovery nutrition are rehydration and refueling which are covered in other papers in this volume. Here, we highlight the benefits for dietary protein intake over and above requirements set out in various countries at ∼0.8–1.0 g·kg body mass (BM)−1·day−1 for training adaptation, manipulating body composition, and optimizing performance in track and field athletes. To facilitate the remodeling of protein-containing structures, which are turning over rapidly due to their training volumes, track and field athletes with the goal of weight maintenance or weight gain should aim for protein intakes of ∼1.6 g·kg BM−1·day−1. Protein intakes at this level would not necessarily require an overemphasis on protein-containing foods and, beyond convenience, does not suggest a need to use protein or amino acid-based supplements. This review also highlights that optimal protein intakes may exceed 1.6 g·kg BM−1·day−1 for athletes who are restricting energy intake and attempting to minimize loss of lean BM. We discuss the underpinning rationale for weight loss in track and field athletes, explaining changes in metabolic pathways that occur in response to energy restriction when manipulating protein intake and training. Finally, this review offers practical advice on protein intakes that warrant consideration in allowing an optimal adaptive response for track and field athletes seeking to train effectively and to lose fat mass while energy restricted with minimal (or no) loss of lean BM.
Ina Garthe, Truls Raastad, Per Egil Refsnes, Anu Koivisto and Jorunn Sundgot-Borgen
When weight loss (WL) is necessary, athletes are advised to accomplish it gradually, at a rate of 0.5–1 kg/wk. However, it is possible that losing 0.5 kg/wk is better than 1 kg/wk in terms of preserving lean body mass (LBM) and performance. The aim of this study was to compare changes in body composition, strength, and power during a weekly body-weight (BW) loss of 0.7% slow reduction (SR) vs. 1.4% fast reduction (FR). We hypothesized that the faster WL regimen would result in more detrimental effects on both LBM and strength-related performance. Twenty-four athletes were randomized to SR (n = 13, 24 ± 3 yr, 71.9 ± 12.7 kg) or FR (n = 11, 22 ± 5 yr, 74.8 ± 11.7 kg). They followed energy-restricted diets promoting the predetermined weekly WL. All athletes included 4 resistance-training sessions/wk in their usual training regimen. The mean times spent in intervention for SR and FR were 8.5 ± 2.2 and 5.3 ± 0.9 wk, respectively (p < .001). BW, body composition (DEXA), 1-repetition-maximum (1RM) tests, 40-m sprint, and countermovement jump were measured before and after intervention. Energy intake was reduced by 19% ± 2% and 30% ± 4% in SR and FR, respectively (p = .003). BW and fat mass decreased in both SR and FR by 5.6% ± 0.8% and 5.5% ± 0.7% (0.7% ± 0.8% vs. 1.0% ± 0.4%/wk) and 31% ± 3% and 21 ± 4%, respectively. LBM increased in SR by 2.1% ± 0.4% (p < .001), whereas it was unchanged in FR (–0.2% ± 0.7%), with significant differences between groups (p < .01). In conclusion, data from this study suggest that athletes who want to gain LBM and increase 1RM strength during a WL period combined with strength training should aim for a weekly BW loss of 0.7%.
James A. Betts, Javier T. Gonzalez, Louise M. Burke, Graeme L. Close, Ina Garthe, Lewis J. James, Asker E. Jeukendrup, James P. Morton, David C. Nieman, Peter Peeling, Stuart M. Phillips, Trent Stellingwerff, Luc J.C. van Loon, Clyde Williams, Kathleen Woolf, Ron Maughan and Greg Atkinson
Ronald J. Maughan, Louise M. Burke, Jiri Dvorak, D. Enette Larson-Meyer, Peter Peeling, Stuart M. Phillips, Eric S. Rawson, Neil P. Walsh, Ina Garthe, Hans Geyer, Romain Meeusen, Luc van Loon, Susan M. Shirreffs, Lawrence L. Spriet, Mark Stuart, Alan Vernec, Kevin Currell, Vidya M. Ali, Richard G.M. Budgett, Arne Ljungqvist, Margo Mountjoy, Yannis Pitsiladis, Torbjørn Soligard, Uğur Erdener and Lars Engebretsen
Nutrition usually makes a small but potentially valuable contribution to successful performance in elite athletes, and dietary supplements can make a minor contribution to this nutrition program. Nonetheless, supplement use is widespread at all levels of sport. Products described as supplements target different issues, including the management of micronutrient deficiencies, supply of convenient forms of energy and macronutrients, and provision of direct benefits to performance or indirect benefits such as supporting intense training regimens. The appropriate use of some supplements can offer benefits to the athlete, but others may be harmful to the athlete’s health, performance, and/or livelihood and reputation if an anti-doping rule violation results. A complete nutritional assessment should be undertaken before decisions regarding supplement use are made. Supplements claiming to directly or indirectly enhance performance are typically the largest group of products marketed to athletes, but only a few (including caffeine, creatine, specific buffering agents and nitrate) have good evidence of benefits. However, responses are affected by the scenario of use and may vary widely between individuals because of factors that include genetics, the microbiome, and habitual diet. Supplements intended to enhance performance should be thoroughly trialed in training or simulated competition before implementation in competition. Inadvertent ingestion of substances prohibited under the anti-doping codes that govern elite sport is a known risk of taking some supplements. Protection of the athlete’s health and awareness of the potential for harm must be paramount, and expert professional opinion and assistance is strongly advised before embarking on supplement use.