Validity of Dietary Assessment in Athletes: A Systematic Review

Abstract

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.

Diet Macronutrient Composition, Physical Activity, and Body Composition in Soldiers During 6 Months Deployment

“…However, food diaries often underestimate nutrient intake due to underreporting (24), which can lead to lower reported energy intake levels. Inaccuracy and forgetfulness may also distort data of food diaries (24).…”

Low energy availability in male athletes: A systematic review of incidence, associations, and effects

“…Alternative methods of assessing energy intake, such as digital photography, have been used to increase the validity and accuracy of energy intake estimation. However, athletes have been known to change their habitual food intake or omit certain foods that they feel may be considered “unhealthy” or that are difficult to measure …”

“…The increased water turnover during lactation resulted in the slope of the isotope disappearance appearing more similar, which inferred an error in estimates of energy expenditure, therefore indicating the DLW method may not be appropriate for use in certain cohorts . A recent meta‐analysis by Capling et al also suggested that a similar error may occur in athletes when using DLW to measure TDEE due to the high water turnover associated with physical activity. It is important to note, however, that the linear relationship between EE and HR is unreliable at resting and at lower aerobic intensity workloads .…”

SPRINTING. . . Dietary Approaches to Optimize Training Adaptation and Performance

“…Dietary survey literature relating to sprint athletes suggests that they typically report daily carbohydrate intakes of 4-6 g/kg body mass, independent of gender (Table 4). Although this may appear low relative to the intakes of endurance athletes and may be amplified by underreporting common among dietary assessment methodology (Capling et al, 2017), there is no conclusive evidence of benefit from maintaining a high habitual carbohydrate intake among sprint athletes. Given the lower relative energy expenditure of larger athletes, their requirements for other nutrients, plus the effect of adjusting carbohydrate on total energy intake, recommendations for carbohydrate intake at strategic times, including before, during, and after exercise, may be more applicable for the sprint athlete.…”

“…The dietary intakes of sprint athletes are poorly represented in the literature (Table 4) (Tipton et al, 2007) and may not accurately represent current practice, given the validity of methods used (Capling et al, 2017). When contrasted against other track-andfield athletes, relative energy and macronutrient intake are lower among sprinters than in the intake of middle-distance and longdistance runners (Sugiura et al, 1999).…”