Multiple day food records or diaries require individuals to record all foods and beverages consumed over a specified period of time, often 3-7 days. Participants are typically asked to carry the paper record or diary with them and to record foods in real time as eaten. However, in reality, many participants will record everything at the end of the day due to the burden of recording in real time. Some protocols require participants to weigh and/or measure foods before eating, while less stringent protocols use food models, photographs of food, measuring cups, and other aids to instruct respondents on estimating serving sizes. Often the food diary is carefully reviewed or documented by a trained dietitian to confirm food portion sizes, ingredients added in cooking and at the table (such as salt, oils, salad dressings, butter, and other condiments), and additional food details. However, this type of detailed review and documentation can add greatly to the participant burden since the minutiae required can seem overwhelming and time consuming to participants. In addition, this type of very detailed documentation adds to the overall cost of food record collection, but may not add significant or necessary food details. One study showed that when detailed, step-by-step instructions on food recording are provided to participants (including specific examples) prior to starting the diary, the detailed documentation by a dietitian may not be necessary (Kolar et al, 2005). Review by a dietitian can still occur during the data entry phase and follow-up queries can be made to the participants, as necessary, but the face-to-face questions and queries could be skipped when sufficient instruction is provided.
Regardless of the data collection protocol, ultimately the food consumption information from records/diaries must be coded and entered into a software program for calculation of nutrient intakes (Schakel et al, 1997). This data entry step is a time consuming task and requires trained data technicians or nutritionists. One reason these complex tasks are so time consuming is that the large food databases typically contain 15,000-20,000 individual food items, which represent only a fraction of the universe of food possibilities. Thus, the trained nutrition coder must make decisions about which foods to enter as substitutes. For example, an individual records "one 4-inch by 4-inch by 4-inch portion of 'Mama's' brand frozen lasagna." If "Mama's" is not listed among the various frozen lasagna choices in the database, the coder must make an informed decision about which brand is the closest match to "Mama's" in terms of total energy, protein, fat, and other nutrients. Some misclas-sification is unavoidable, but a well-trained and knowledgeable nutritionist should be able to select comparable substitutes.
Food records are somewhat burdensome for clients or study participants to complete. In fact, some studies have shown that individuals might change their food intake on recording days to consume more easy-to-prepare items that require less recording, but the ultimate influence of this practice is unknown (Craig et al, 2000; Rebro et al, 1998). Clients or study participants should always be reminded to eat as they normally do during the food-recording period. Advances in digital mobile devices (phones, cameras, PDAs) now make it possible to record and transmit food record data, which alleviates some of this participant burden and may provide more accurate data (Beasley et al, 2005; Kretsch and Fong, 1990; Wang et al, 2002). Digital devices are becoming such a routine part of people's lives that realtime digital recording of one's food and beverage intake may not feel as burdensome as a paper and pencil diary. Other disciplines in medicine, physical activity, and pain monitoring have been successfully using technological advances for quite sometime (Berg et al, 1998; Jamison et al, 2001). In addition, digital recording of food intake may alleviate problems with portion size estimation, which is a frequent source of error in dietary data collection (Williamson et al, 2003, 2004). In the future, pencil and paper food diaries are likely to disappear in favor of digital collection methods.
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