Information on dietary composition is vitally important for elite athletes to optimise their performance and recovery. This requires valid tools to advise and monitor athletes' intake. The aim of the present PhD program is to get insight in the dietary intake of elite athletes by multiple 24-hour recalls and questionnaires and their reporting of the use of dietary supplements and sports nutrition products.
During the project also the validity of the survey method is investigated. This is done trough assessing protein intake by multiple 24-hour recalls and questionnaires, by comparing these with multiple urinary nitrogen excretions.
Dietary composition and timing of food intake are vitally important for elite athletes to optimise their performance and recovery. Requirements differ between elite athletes and physically less active people. This demands for adequate insight in dietary intake to advise and monitor the intake of athletes.
Food records and 24-hour recalls are commonly used to assess current intake or intake of the recent past. To assess dietary intake by athletes at a group level both, 3-4 day or 7-day food records and multiple 24-hour recalls have been used. These methods, however, show large differences in validity between different populations.
The 21st century athlete, often combining intensive training and competition programmes with college education, demands practical dietary assessment methods like web-based, 24-hour recalls. The advantage of the 24-hour recall is that the outcome is not affected by awareness and consequently an altered –desirable - intake as seen with the use of a food record. Also by using web-based recalls athletes can report their intake, within certain limits, at their own convenience. The preferred five-step, multiple pass, 24-hour recall is highly standardised and results in a reliable estimation of dietary intake.
Information about dietary intake and the validity of self-reported dietary intake in elite athletes is scarce. Their active lifestyle with intensive training programmes generates methodological problems. To our knowledge, no recent data about the Dutch athlete has been published. Besides this, no validation studies have been undertaken to estimate the accuracy of multiple 24-hour recalls to assess protein intake in athletes. Therefore, the aim of this project is to get more insight in nutritional intake of elite athletes and investigate the validity of the used method.
The following studies are part of this project:
- Validation of nutritional intake in elite athletes based on multiple 24-hour nitrogen excretions.
- Daily nutrition and supplement intake of top- and elite athletes: macro-nutrients
- Daily nutrition and supplement intake of top- and elite athletes: micro-nutrients
- Nutrient intake by ultramarathon runners: can they meet recommendations?
- Sports nutrition and supplement intake of the general Dutch population.
- Sports nutrition and supplement intake of top- and elite athletes: self reported knowledge, attitude and behavior.