Context: Nutrition education aims to enhance knowledge and improve dietary intake in athletes. Understanding athletes’ nutrition knowledge and its influence on dietary intake will inform nutrition-education programs in this population.Purpose: To systematically review the level of nutrition knowledge in athletes, benchmark this against nonathlete comparison groups, and determine the impact of nutrition knowledge on dietary intake.Methods: An extensive literature search from the earliest record to March 2010 using the terms nutrition knowledge or diet knowledge and athlete or sport was conducted. Included studies recruited able or physically disabled, male or female, competitive (recreational or elite) athletes over the age of 13 yr. Quantitative assessment of knowledge and, if available, diet intake was required. Because of variability in the assessment of nutrition knowledge and dietary intake, meta-analysis was not conducted.Results: Twenty-nine studies (17 published before 2000) measuring nutrition knowledge (7 including a nonathlete comparison group) met inclusion criteria. Athletes’ knowledge was equal to or better than that of nonathletes but lower than comparison groups including nutrition students. When found statistically significant, knowledge was greater in females than males. A weak (r < .44), positive association between knowledge and dietary intake was reported in 5 of 9 studies assessing this. Common flaws in articles included inadequate statistical reporting, instrument validation, and benchmarking.Conclusion: The nutrition knowledge of athletes and its impact on their dietary intake is equivocal. There is a need for high-quality, contemporary research using validated tools to measure nutrition knowledge and its impact on dietary intake.

Dietary assessment methods that are recognized as appropriate for the general population are usually applied in a similar manner to athletes, despite the knowledge that sport-specific factors can complicate assessment and impact accuracy in unique ways. As dietary assessment methods are used extensively within the field of sports nutrition, there is concern the validity of methodologies have not undergone more rigorous evaluation in this unique population sub-group. The purpose of this systematic review was to compare two or more methods of dietary assessment, including dietary intake measured against biomarkers or reference measures of energy expenditure, in athletes. Six electronic databases were searched for English-language, full-text articles published from January 1980 until June 2016. The search strategy combined the following keywords: diet, nutrition assessment, athlete, and validity; where the following outcomes are reported but not limited to: energy intake, macro and/or micronutrient intake, food intake, nutritional adequacy, diet quality, or nutritional status. Meta-analysis was performed on studies with sufficient methodological similarity, with between-group standardized mean differences (or effect size) and 95% confidence intervals (CI) being calculated. Of the 1624 studies identified, 18 were eligible for inclusion. Studies comparing self-reported energy intake (EI) to energy expenditure assessed via doubly labelled water were grouped for comparison (n = 11) and demonstrated mean EI was under-estimated by 19% (−2793 ± 1134 kJ/day). Meta-analysis revealed a large pooled effect size of −1.006 (95% CI: −1.3 to −0.7; p < 0.001). The remaining studies (n = 7) compared a new dietary tool or instrument to a reference method(s) (e.g., food record, 24-h dietary recall, biomarker) as part of a validation study. This systematic review revealed there are limited robust studies evaluating dietary assessment methods in athletes. Existing literature demonstrates the substantial variability between methods, with under- and misreporting of intake being frequently observed. There is a clear need for careful validation of dietary assessment methods, including emerging technical innovations, among athlete populations.

Purpose: This study aimed to compare strategies for assessing nutritional adequacy in the dietary intake of elite female athletes.Methods: Dietary intake was assessed using an adapted food-frequency questionnaire in 72 elite female athletes from a variety of sports. Nutritional adequacy was evaluated and compared using mean intake; the proportion of participants with intakes below Australian nutrient reference values (NRV), U.S. military dietary reference intakes (MDRI), and current sports nutrition recommendations; and probability estimates of nutrient inadequacy.Results: Mean energy intake was 10,551 ± 3,836 kJ/day with macronutrient distribution 18% protein, 31% fat, and 46% carbohydrate, consistent with Australian acceptable macronutrient distribution ranges. Mean protein intake (1.6 g · kg⁻¹ · d⁻¹) was consistent with (>1.2 g · kg⁻¹ · d⁻¹), and carbohydrate intake (4.5 g · kg⁻¹ · d⁻¹), below, current sports nutrition recommendations (>5 g · kg⁻¹ · d⁻¹), with 30% and 65% of individuals not meeting these levels, respectively. Mean micronutrient intake met the relevant NRV and MDRI except for vitamin D and folate. A proportion of participants failed to meet the estimated average requirement for folate (48%), calcium (24%), magnesium (19%), and iron (4%). Probability estimates of inadequacy identified intake of folate (44%), calcium (22%), iron (19%), and magnesium (15%) as inadequate.Conclusion: Interpretation of dietary adequacy is complex and varies depending on whether the mean, proportion of participants below the relevant NRV, or statistical probability estimate of inadequacy is used. Further research on methods to determine dietary adequacy in athlete populations is required.

Competitive bodybuilders undergo strict dietary and training practices to achieve an extremely lean and muscular physique. The purpose of this study was to identify and describe different dietary strategies used by bodybuilders, their rationale, and the sources of information from which these strategies are gathered. In-depth interviews were conducted with seven experienced (10.4 ± 3.4 years bodybuilding experience), male, natural bodybuilders. Participants were asked about training, dietary and supplement practices, and information resources for bodybuilding strategies. Interviews were transcribed verbatim and analyzed using qualitative content analysis. During the off-season, energy intake was higher and less restricted than during the in-season to aid in muscle hypertrophy. There was a focus on high protein intake with adequate carbohydrate to permit high training loads. To create an energy deficit and loss of fat mass, energy intake was gradually and progressively reduced during the in-season via a reduction in carbohydrate and fat intake. The rationale for weekly higher carbohydrate refeed days was to offset declines in metabolic rate and fatigue, while in the final “peak week” before competition, the reasoning for fluid and sodium manipulation and carbohydrate loading was to enhance the appearance of leanness and vascularity. Other bodybuilders, coaches and the internet were significant sources of information. Despite the common perception of extreme, non-evidence-based regimens, these bodybuilders reported predominantly using strategies which are recognized as evidence-based, developed over many years of experience. Additionally, novel strategies such as weekly refeed days to enhance fat loss, and sodium and fluid manipulation, warrant further investigation to evaluate their efficacy and safety.