The preceding chapters have provided us with an overview of the nutrients needed for good health and performance. In order to understand where these nutrients come from when we eat foods as part of our daily lives, we need to collect information about what people eat. Dietitians and nutritionists use many different types of tools, referred to as dietary assessment methods, to collect this information. To translate the food information into nutrient outcomes, we also need to use tools called food composition databases. In this chapter, we will explore some of the most common dietary assessment tools and address some considerations we need to be aware of when using food composition databases.
LEARNING OUTCOMES
Upon completion of this chapter you will be able to:
• describe common methods of dietary assessment, with particular focus on their strengths and limitations
• understand how food information can be translated to nutrient outcomes
• appreciate how dietary guidelines and nutrition policies can be used with dietary assessment information
• describe aspects of dietary assessment important in sports, including the timing of snacks or meals relative to training and competition.
Dietary assessment is the process by which we find out what a person or group of people are eating and drinking. This is fundamental to the skills of a dietitian but may also be important for other health and fitness professionals to gain an understanding of people’s food habits. Dietary assessments can be obtained at the time foods and drinks are consumed, or they can be performed retrospectively, after foods and drinks have been eaten, often relying heavily on a person’s memory. To help capture the required information, a range of assessment methods have been developed and refined over time, each with their own advantages and disadvantages. These factors are unique to the situation in which the assessment method is being used and the individual or group with whom it is being used. Capturing dietary information for a five-year-old child, for example, will have many different considerations than capturing dietary information from an adult who lives alone and does all their own cooking and shopping. Not only will the types of tools used need to be considered but the impact of other factors will also need to be thought through. These other factors include things such as bias and literacy, which will be addressed below in relation to each of the specific assessment methods. The assessment methods vary in terms of how they are undertaken but also in relation to the form in which the food information is collected. This form can be pen and paper, or it can be in various digital formats. After the food information has been collected, careful consideration needs to be given to how the information will be used. Is nutrient information needed from the foods that were reportedly eaten or will these foods be related to dietary guideline recommendations? These two options will be discussed later in this chapter.
DIETARY ASSESSMENT METHODS
The types of dietary assessment methods that are commonly used include those based on recall and memory, such as the 24-hour recall (National Cancer Institute; Salvador Castell et al. 2015), the diet history interview (Tapsell et al. 2000) and the food frequency questionnaire (National Cancer Institute; Perez Rodrigo et al. 2015). Other assessments capturing intake at the time of consumption—namely, the food record or food diary—may also be used in isolation or in parallel with the other methods. These tools are then further categorised into whether they are capturing actual intake or usual intake information. The food record or food diary is the most suitable tool to capture actual food intake information. This assessment method requires a person to write down the names and brand names of all foods and beverages consumed by meal occasion and to quantify the amount consumed. The way in which this quantity is determined creates the differentiating factor between an estimated food record and a weighed food record. As the name suggests, an estimated food record only requires an estimate of portion size in terms the person recording the foods can relate to. A weighed food record, on the other hand, requires the person recording the foods to accurately measure and weigh all items to be consumed. This includes a breakdown of ingredients required for a food that is cooked as part of a recipe and requires the person to take the measuring equipment with them to all eating occasions. As a result, although the accuracy of the recorded food items should be higher than an estimated record, often subconscious or conscious changes to the types of food eaten occur and the actual intake is distorted. To reduce the impact of this bias, digital food records have been developed whereby the user takes photographs of the food being consumed before and after eating. Using images to capture the food items also reduces the burden related to the number of days of recording. Having more days required often results in less detailed information being provided, which also substantially affects the accuracy. As a result, the most common duration is the three-day estimated food record, which includes at least one weekend day.
Estimated food record
A form of dietary assessment in which a person records all the food and drink they have consumed by estimating the weight or serving size of the food.
A form of dietary assessment in which a person records with weights and volumes all the food and drink they have consumed.
A 24-hour dietary assessment follows a structured approach to dietary assessment by capturing information about foods and beverages consumed during the previous day or 24-hour period. Often administered by an interviewer, this form of assessment alone cannot capture usual intake information about the diet unless it is repeated over a number of occasions. During a 24-hour recall the interviewer follows a multiple pass approach to guide the interviewee’s recall of their food and beverage intakes. This approach begins with a free-flowing recall of all items in the order they were consumed. The process is uninterrupted to allow the interviewee to recall an unprompted food list. This list is then addressed from the beginning to obtain further detail about the food item types, accompanying foods and commonly forgotten items, as well as the portion size of each of the foods and beverages recalled. The recalls often follow a meal-based format, although the eating occasion, timing and location may also be collected depending upon the requirements.
Like the 24-hour recall, the diet history interview is based on the memory of the person recalling their food and beverage consumption, but the process is largely interviewer-led and addresses usual intake. This usual intake period generally covers a one-month period but can vary substantially, from one week up to one year. The diet history interview follows a similar format to the 24-hour recall; however, its open-ended nature lends itself to recall of foods that are eaten less frequently, during particular seasons or at eating occasions such as birthdays. Guided by the interviewer, a diet history interview is a skill-based dietary assessment method traditionally undertaken by trained dietitians. Often followed up with a checklist of commonly forgotten foods, the diet history interview provides information about the foods eaten by a person, the frequency at which those foods are eaten and the portion size that is usually eaten. This portion size may be guided by household measures such as measuring cups and spoons, by pictorial portion guides or using food models. Both the diet history interview and the 24-hour recall have been automated; the structure of the 24-hour recall lends itself particularly well to this format, with the prompts provided by an avatar on screen rather than in person by the interviewer. This format allows large numbers of people to recall their intakes without the need for additional resources.
Table 7.1. Summary of common dietary assessment methods
| Assessment method | Recording type | Strengths | Limitations |
| Food record | • Prospective (recorded as they are consumed) • Self-administered |
• Actual intake information • Using images reduces burden |
• Increased days are affected by burden • Social desirability bias creates changed intakes • Requires literate persons |
| 24-hour recall | • Retrospective (reflects back on dietary intake) • Multiple pass method • Interviewer assisted |
• Quick to administer • Repeated recalls can give usual intake information • Structured approach |
• Affected by memory • Affected by social desirability bias |
| Diet history interview | • Retrospective • Interviewer prompted |
• Usual intake information • Captures in-depth information |
• Affected by memory • Affected by social desirability bias • Requires interviewer • Requires 30–60 minutes to complete |
| Food frequency questionnaire | • Retrospective • Self-administered • Can be interviewer-assisted |
• Usual intake information • Can be completed over multiple attempts • Can be tailored to requirements, e.g. nutrient type |
• Length of food list affects accuracy • May not be quantified |
Usual intake information may also be collected using a food frequency questionnaire. The questionnaire includes a list of food items suited to the purpose of the information being collected. For example, if the purpose is to determine calcium intake then only calcium-containing foods need be included. The food list may comprise single food items or it may group foods with similar characteristics. The person completing the questionnaire identifies how often the food is consumed based on the frequency categories provided. Food frequency questionnaires may span wide time intervals, with some even referring to the previous year. Food frequency questionnaires can be quantified or semi-quantified, meaning that they may also require information about the portion size most often consumed for each item in the food list. The portion sizes can refer to a standard size that may relate to dietary guidelines, or they may be displayed as images or different size options for each food choice. Inclusion of portion size information may also result in improved response rates. Food frequency questionnaires are commonly self-administered, meaning they do not require an interviewer to ask the questions. This does, however, leave the tool open to interpretation by the person reporting their intake and may lead to missed sections or skipped food items.
TRANSLATING DIETARY INTAKES TO NUTRIENT OUTCOMES
The above section has outlined a number of methods used to find out what food and beverages are being consumed by a person. These methods all result in information related to specific foods and beverages, which may not be of practical use if someone needs to determine how much protein or energy they are consuming. To translate the food and beverage information to nutrient information, tools referred to as food composition databases are used. These databases contain a list of foods available in the food supply and their nutrient information, including both macronutrients and micronutrients. Each country has its own unique food composition database, as many foods are affected by local processing, harvesting, soil conditions, UV exposure, food regulatory environments and many other factors. There is specialised software available to make the use of food composition tables fast and efficient. Although the software is useful, it does require the user to have a basic understanding of which food composition database to choose. If many assessments need to be translated, as is common in research, the person or people using the software need to ensure they use it consistently and follow the same assumptions. It also needs to be appreciated that not every food item found on the supermarket shelf will appear in a food composition database, but generic versions of most foods do exist and therefore careful choices for the correct food match need to be made.
Food composition databases
Databases that contain lists of foods available in the food supply and their nutrient information including energy, macronutrients and micronutrients.
In Australia, and many other countries across the globe, we have two types of food composition databases: a survey database and a reference database. The survey database contains a complete nutrient set for all the foods listed and is based on the food items reported in the national nutrition survey for which it was developed. Some of this nutrient information is calculated or borrowed from overseas databases but the majority is based on the reference database. The reference database contains fewer food items, although a higher proportion of the items have been analysed in the laboratory to identify the amounts of nutrients in the foods. As a result, some foods may not include the same number of nutrient values and the database is therefore considered incomplete. The survey databases in Australia are referred to as AUSNUT (Australian Nutrient) databases and the reference databases as NUTTAB (Nutrient Tables) databases. The most recent AUSNUT database contains over 5700 food and beverage items, while the most recent NUTTAB database contains slightly more than 2500 food and beverage items (Probst & Cunningham 2015).
Databases that are specifically developed for the analysis of all foods reported in national nutrition surveys. For example, in Australia, AUSNUT was developed for the Australian Health Survey 2011–12.
Reference database
Databases developed from a wide range of foods that are primarily analysed in the laboratory. For example, in Australia, NUTTAB is the reference database.
Box 7.1: National Nutrition and Physical Activity Survey 2011–13
The National Nutrition and Physical Activity Survey 2011–13 was the largest and most comprehensive food- and physical activity-related survey conducted in Australia. It involved the collection of detailed physical activity information using self-reported and pedometer collection methods, along with detailed information on dietary intake and foods consumed from over 12,000 participants across Australia. The nutrition component is the first national nutrition survey of adults and children (aged two years and over) conducted in over 15 years. More information and data can be found at the Australian Bureau of Statistics Australian Health Survey webpage (ABS 2014) <http://www.abs.gov.au/ausstats/abs@.nsf/lookup/4364.0.55.007main+features12011-12>.
To translate food and beverage information to nutrient information the survey, or AUSNUT, database should be used. As this contains a complete set of nutrient values, it will result in better quality nutrient outcomes with less incomplete data (Sobolewksi et al. 2010). The NUTTAB database can also be used, but is more useful when working out how much of a particular nutrient is in one or a few food items or when developing a specialised menu plan. Using NUTTAB ensures the nutrient values are primarily analysed in the laboratory and therefore more accurate. Where no matching food information is available, food label information may be used, but this is considered lower quality data as it is often based on calculations and limited to the nutrients required to be listed under the various regulatory codes and policies.
USING DIETARY GUIDELINES AND POLICIES IN PRACTICE
By now you will have read about the Australian Dietary Guidelines and how they were developed (Chapter 6). Armed with food information from a dietary assessment, and nutrient information obtained by using food composition databases, we now need to think about how we can use this information with our clients. The most common approach relates the food consumed to the Australian Dietary Guidelines (NHMRC 2013). These guidelines are designed to maximise intake from core food groups and limit consumption of foods known as discretionary sources. This comparison can be made using data collected through any of the assessment methods described in this chapter, although care needs to be taken that any recommendations based on this comparison are relevant for the individual client. For this reason, readily available and consumer-friendly resources, such as the Australian Guide to Healthy Eating, can be used to guide discussions with clients around portion sizes and the balance and types of foods being consumed, using the suggested serves per day for each of the food groups. Conversations based on the Australian Dietary Guidelines are considered to be within the scope of practice for trained nutrition, exercise and fitness professionals. However, more specific and personalised dietary planning is the speciality of dietitians; hence, when working with athletes it is best to refer to a dietitian if you are not specifically trained as one (https://daa.asn.au/find-an-apd/).
Other useful tools that can be aligned with dietary assessment outcomes are the Nutrient Reference Values (NRV) (NHMRC 2006) discussed in Chapter 4. After translating food and beverage information to nutrient intakes, the appropriate NRV can be used as a comparator to determine adequacy of intake. A person consuming insufficient amounts of important nutrients may need to increase or balance the foods that they are eating. Given that insufficient intake of some nutrients can result in deficiency symptoms, while overconsumption can result in toxicity symptoms, adjustments based on nutrient concerns are best supported by a trained dietitian. The dietitian will be able to consider the medical, lifestyle and exercise-related factors relevant to the individual and identify any possible medication interactions or underlying concerns as to why the nutrient levels are outside of the normal ranges. It is important to note that nutrient information taken directly from a dietary assessment method and translated using a food composition database can be affected by bias (see limitations in Table 7.1). For this reason, if the dietitian expresses concern he or she will likely suggest further medical intervention via a general practitioner.
Applying dietary assessment to sports
Although the Australian Dietary Guidelines are developed for the general population, the messages are applicable to many sporting practices as well. It should be noted, however, that the level and types of training undertaken by sporting professionals or athletes may require additional or modified guidance to optimise health and wellbeing. The long or intensive training sessions and competitive events require athletes to be at optimum performance for a given time period. The timing of such events may last for a season or for shorter intermittent periods of time throughout a year. Not only does the food eaten need to be taken into consideration but beverages and their amounts are also crucial to allow the athlete to perform at their best.
Following a dietary assessment, each of the above factors needs to be addressed with the athlete. Are they in an off-season period? Are they training or are they competing? The type of sport being undertaken, whether it is primarily strength- or endurance-focused, and the athlete’s age, health status and sex should also be addressed. Many sports require careful timing of athletes’ fluid intake, snacks and meals relative to their training schedule and intensity and their competitive games or events. The composition of these meals needs to be managed. Too much or too little of key nutrients, such as protein, carbohydrate and fat, which all provide energy to the body, can disrupt optimal performance and result in an athlete feeling lethargic or bloated or experiencing stomach cramps. Dietary planning needs to ensure that the athlete follows a general healthy, balanced diet with personalised adjustments made to the above nutrients via key foods as needed.
For a dietary assessment of an athlete, a diet history interview will likely capture the most in-depth food and beverage information and also allow a history of subjective factors—such as mood and perceived effects on performance—to be obtained. The interviewer has the ability to focus on key training and periods in the lead-up to an event while also considering other lifestyle-related factors that may impact the individual. Variation in dietary assessments due to the variable lifestyles of many athletes should also be taken into account. On some occasions more detail may be required, and a food record or diary may be used as well. This provides accountability for the athlete if they have been asked to follow a very specific eating plan and also raises awareness of serving sizes in relation to recommended portion sizes. The food record can also capture the time of the meals and record time of training to allow for meal plans to be tailored based on feedback from the athlete. The food diary should also endeavour to capture fluid intakes, even though beverages are often more intermittently consumed.
In the lead-up to an event, a 24-hour recall may also provide useful insights. Common recommendations for some sports, such as the timing and composition of pre-game meals and snacks, can be monitored with a quick recall. The recall can also capture information about food intake following an event and allow adjustments to be made to the food choices if needed to promote recovery.
Some sports have specific guidelines developed for them, based on the Australian Dietary Guidelines but tailored to the specific needs of the athletes. Accredited Sports Dietitians should be consulted to ensure any meal plans being followed are tailored to the individual.
SUMMARY AND KEY MESSAGES
After reading this chapter, you should be familiar with a range of dietary assessment methods. You should be able to identify which tools are most appropriate to use in different circumstances, and be able to outline the limitations associated with those methods. You should also have a basic understanding of food composition databases and be able to select the appropriate database for use in a specific context.
Key messages
• Dietary assessment methods need to be carefully selected based on the person or group of people whose diet needs to be assessed.
• All dietary assessment methods have inherent advantages and disadvantages.
• When translating food information from a dietary assessment, the correct food composition database needs to be selected.
• Dietary guidelines and Nutrient Reference Values may also be used as comparative tools when analysing a person’s dietary intake.
Assessing dietary intakes of an athlete requires consideration of the type of sport being undertaken, as well as lifestyle factors, which can all be addressed by an Accredited Practising Sports Dietitian.
REFERENCES
Australian Bureau of Statistics, 2014, Australian Health Survey: Nutrition First Results–Foods and Nutrients, 2011–12 [Online], Australian Bureau of Statistics, <http://www.abs.gov.au/ausstats/abs@.nsf/Lookup/by%20Subject/4364.0.55.007~2011-12~Main%20Features~Key%20Findings~1>, accessed 29 January 2018.
National Cancer Institute, n.d., Dietary Assessment Primer: 24-Hour Dietary Recall (24HR) at a Glance, retrieved from <https://dietassessmentprimer.cancer.gov/profiles/recall/index.html>, accessed 5 December 2017.
—— n.d., Dietary Assessment Primer: Food Frequency Questionnaire at a glance, retrieved from <https://dietassessmentprimer.cancer.gov/profiles/questionnaire/index.html>.
—— n.d., Dietary Assessment Primer: Food Record at a Glance, retrieved from <https://dietassessmentprimer.cancer.gov/profiles/record/>.
National Health and Medical Research Council (NHMRC) 2006, Nutrient Reference Values, <www.nrv.gov.au/>, accessed 22 September 2017.
—— 2013, Eat for Health: Australian Dietary Guidelines Summary, retrieved from <www.nhmrc.gov.au/_files_nhmrc/publications/attachments/n55a_australian_dietary_guidelines_summary_131014.pdf>.
Perez Rodrigo, C., Aranceta, J., Salvador, G. et al., 2015, ‘Food frequency questionnaires’, Nutricion Hospitalaria, vol. 31, no. 3, pp. 49–56.
Probst, Y.C. & Cunningham, J., 2015, ‘An overview of the influential developments and stakeholders within the food composition program of Australia’, Trends in Food Science and Technology, vol. 42, no 2, pp. 173–82.
Salvador Castell, G., Serra-Majem, L. & Ribas-Barba, L., 2015, ‘What and how much do we eat? 24-hour dietary recall method’, Nutricion Hospitalaria, vol. 31, no. 3, pp. 46–8.
Sobolewksi, R., Cunningham, J. & Mackerras, D., 2010, ‘Which Australian food composition database should I use?’, Nutrition & Dietetics, vol. 67, no. 1, pp. 37–40.
Tapsell, L.C., Brenninger, V. & Barnard, J., 2000, ‘Applying conversation analysis to foster accurate reporting in the diet history interview’, Journal of the American Dietetic Association, vol. 100, no. 7, pp. 818–24.