Nutrition Assessment

Methods for Obtaining Information about Dietary Intake: There are a variety of options for obtaining information about food intake. The basic options include a 24-hour recall, food record or diary, dietary history, food frequency questionnaires, and quick screeners. There are advantages and disadvantages to using each method. Using multiple methods is time consuming but can overcome the inherent limitations of each method. As the ethnic and age diversity of the target population increase, the need for open-ended questions and obtaining data by interviewing also increase.

24-Hour Recall: The 24-hour recall is widely used in clinical practice and for national food surveys. The United States Department of Agriculture (USDA) has developed a five-step multiple pass interview to reduce the risk of under reporting food intake. These steps include: 1) Quick food list -The respondent reports an uninterrupted listing of all food and beverages consumed during the day (to cover a 24-hour period) before the interview. 2) Forgotten food list – The interviewer asks about foods that the respondent may have forgotten in nine food categories (nonalcoholic beverages, alcoholic beverages, sweets, savory snacks, fruits and vegetables, cheese, breads and rolls, and any other foods. 3) Time and occasion – The interviewer asks about the time the respondent began eating or drinking each item reported and what the respondent can recall about each eating occasion. 4) Detail cycle – The interviewer standardized questions developed by the USDA about how to probe for information about the foods eaten, preparation methods, ingredients, etc. The detail cycle also included a review of eating occasions and time between occasions. 5) Final review and Probe – The interviewer asks about any else consumed trying to help the respondent remember any forgotten items. Studies have documented that calorie determinations based on patient interviews are not particularly accurate and that obese patients tend to underestimate portion sizes. A more recent study found that both normal weight and obese women provided estimates of macronutrient and calorie intake that were within 10% of actual intake when interviewed by telephone using the USDA 5-step multiple pass method. The obese women were more accurate in their estimations of calorie intake than the normal weight women. However, the USDA 5-step process requires 20-30 minutes and visual aids to facilitate portion size estimation. While dietitians may use some of the probing techniques developed by the USDA to elicit more details about target nutrient intake in their interviews with patient, but primary care clinicians will no doubt find routine use of multiple passes practical. Most clinicians will seldom have more that a few minutes to for obtaining a food recall. A brief interview can identify key behavioral and food patterns associated with target nutrient excess or inadequacy.

Food Record or Food Diary: Food records and diaries involve writing down food items soon after there are eaten for a specified period of time. Self-monitoring diaries that combine several methods can be used over extended periods of time. Computerized devices may also be used to reduce the burden of self-monitoring, but the database of foods needs to include items consumed by the users . A food record for several days, which includes weighing foods before they are eaten, can provide a detailed and valid assessment of food actually eaten. However, the act of recording can alter intake and thus limit the potential for accurately reflecting typical intake. The accuracy of food records is increased by training patients to measure or estimate portion sizes and to provide a more detailed description of food eaten. The burden of recording food intake is substantial and can be intimidating to clients with a limited education level. When food records are used in research, an interview is used to clarify portion size and preparation methods as well as to elicit food items that may have been forgotten. As the number of days of food recording increase, the ability to characterize the nutrient intake of an individual improves. A few days are needed to estimate macronutrient and energy intake which tend to be relative consistent from day to day. For micro nutrients, such as beta-carotene, which are concentrated in relative few foods, the number of days required to characterize intake increases. Food Frequency Questionnaire (FFQ): FFQ are usually self-administered instruments that list commonly eaten foods by food groups. The response frame is designed to elicit how frequently listed items are consumed. The response options usually include columns for daily, times per week, month and/or year. FFQs may include an open format to add items that may be frequently consumed by a relatively small subset of those completing the questionnaire. This approach facilitates being able tailor the use of FFQs for ethnically diverse populations. However, staff assistance may be needed to elicit these items. FFQs may also include listings of nutrient/herbal supplements. Typically, FFQs underestimate energy intake but may over estimate micronutrients intake. Software for analyzing the National Cancer Institute (NCI) FFQ is available free of charge but other FFQs are propriety. Subar et al have compared the validity of the NCI Block and Willet FFQs.

Dietary Histories: Dietary histories range from questionnaires that utilize questions from major national government surveys to FFQs. Historically, a dietary history used a triangulation of methods combining a 3-day food record, a FFQ, a 24-hour recall, and questions about typical food intake. More recently, economic concerns have focused on food insecurity and worries about having enough money to purchase food. Ironically, food insecurity needs to be assessed as an integral component of a dietary history focused on chronic disease because of its link to obesity.

Brief Dietary Scanners: Many of the dietary assessment methods used in clinical practice require too much time to be used in a community setting or large managed care organization. They may assess adherence to a set of recommendations such as the ATP III guidelines or screen for key behaviors such as Weight, Activity, Variety and Excess. Some are self-administered and others are can be obtained in a brief interview.