What is a 24-hour recall? A Guide to Dietary Assessment

December 12, 2025 •

3 min read

Used widely in national nutritional surveys, a 24-hour recall is a retrospective method for monitoring and assessing an individual's food and drink consumption over the previous 24 hours. This structured interview is a cornerstone tool for health professionals seeking to understand dietary patterns and nutrient intake.

Quick Summary

A 24-hour recall is a structured dietary interview where a person reports all food and beverages consumed in the past 24 hours. The multiple-pass method aids memory for accurate data collection on types, quantities, and preparation methods.

Key Points

Retrospective Method: The 24-hour recall is a dietary assessment tool that asks a person to remember and report all food and drinks consumed over the previous 24-hour period.
Multiple-Pass Technique: To improve accuracy, the method often uses a multi-step interview process to help the respondent remember all consumed items, portion sizes, and preparation details.
High Level of Detail: It provides highly specific information on food types, cooking methods, and quantities, offering a snapshot of recent dietary habits.
Low Participant Burden: A single interview is relatively quick and does not alter eating behavior, making it a low-effort assessment for the respondent.
Not for Individual Usual Intake: A single 24-hour recall is not representative of a person's long-term eating patterns and requires multiple, non-consecutive days for assessing habitual intake.
Reliant on Memory: The method is inherently dependent on the respondent's ability to accurately recall their intake, which can introduce recall and social desirability biases.

Understanding the 24-Hour Recall Method

A 24-hour dietary recall (24HR) is a detailed, retrospective interview used by nutritionists, dietitians, and researchers to capture a person's complete dietary intake over a 24-hour period, typically the previous day. This method is crucial for understanding eating patterns and calculating nutritional intake at both the individual and population level. Unlike long-term food frequency questionnaires, the 24HR focuses on a very specific, recent time frame, which helps reduce the burden on a respondent's long-term memory.

The accuracy of a 24HR relies heavily on the respondent's memory and the interviewer's skills. To maximize completeness and accuracy, standardized protocols have been developed, most notably the multiple-pass method. Automated systems also now facilitate this process, allowing for remote, online data collection.

The Multiple-Pass Method in Practice

The multiple-pass technique is a structured approach designed to jog a respondent’s memory and collect the most detailed information possible, guiding the respondent through their previous 24 hours in several stages. You can find a detailed description of each pass in the referenced documents. Key stages include a quick list of consumed items, prompting for forgotten foods and beverages, assigning times and occasions to meals, a detailed cycle to gather specifics on each item (description, portion size, additions), and a final review to ensure completeness. This systematic process helps minimize gaps in reporting and improves the quality of data for nutritional analysis.

Advantages and Limitations of the 24-Hour Recall

While the 24HR is a powerful tool, it comes with a distinct set of strengths and weaknesses that influence its application in research and clinical settings.

Advantages

Detailed Dietary Data: Captures specific information on food types, preparation, and meal patterns.
High Accuracy for Short-Term Intake: Relies on recent, specific memory.
Low Respondent Burden: The interview is relatively quick (20–60 minutes).
Non-reactive: Does not alter eating habits if unannounced.
Suitable for Illiterate Participants: Interviewer-administered recalls don't require literacy.

Limitations

Reliance on Memory: Memory can be fallible.
Single Day Not Representative: A single 24HR cannot capture day-to-day variations; multiple recalls are needed for usual intake.
Recall and Interviewer Bias: Potential for under/over-reporting and interviewer influence.
Cost and Labor Intensive: Can be expensive, though automation helps.

Comparing 24-Hour Recall and Food Frequency Questionnaires


Characteristic	24-Hour Recall (24HR)	Food Frequency Questionnaire (FFQ)
Time Frame	Previous 24 hours	Usual intake over a longer period (e.g., last year)
Data Detail	High specificity for foods, quantities, and preparation methods	Less specific; relies on predefined food lists and frequency categories
Respondent Burden	Low (single interview is quick)	Low to medium (self-administered and typically shorter)
Memory Type	Specific, recent memory	Generic, long-term memory
Best For	Measuring average intake of a population; validating other methods	Ranking individuals within a population; assessing habitual intake over time
Primary Bias	Recall and interviewer bias	Systematic errors related to memory and predefined food lists

Advancements in 24-Hour Recall Technology

Technology is improving 24HRs, with automated, web-based tools like ASA24 streamlining data collection. These systems use digital aids for portion size estimation and standardize prompts, simplifying data entry and analysis and reducing labor. Automated platforms offer a promising path for more accurate and efficient dietary assessment.

Conclusion: A Versatile Dietary Tool

In summary, what is a 24-hour recall? It is a highly specific, retrospective dietary interview method that, especially when using the multiple-pass technique, provides valuable snapshots of an individual's food and nutrient intake. While a single recall is not representative of a person's habitual diet and requires multiple administrations for individual assessment, its low respondent burden and high level of detail make it an invaluable tool for large-scale population surveys and for validating other dietary assessment methods. As technology continues to advance, automated versions of the 24HR are becoming more accessible and efficient, further solidifying its role in nutritional science and public health.

For more detailed information on dietary assessment methodologies, refer to the resources provided by the National Cancer Institute (NCI).

Frequently Asked Questions

A 24-hour recall is typically administered by a trained interviewer, such as a dietitian or a health professional. In some modern applications, automated, self-administered tools are also used.

No, a single 24-hour recall is generally not sufficient to capture a person's usual, long-term dietary intake due to day-to-day variations. Multiple, non-consecutive recalls are needed for this purpose.

The multiple-pass method is a standardized, multi-stage interviewing technique used for the 24-hour recall to enhance the accuracy and completeness of the reported dietary information by helping the respondent remember forgotten details.

The main limitations include its reliance on memory, the potential for recall bias and social desirability bias, and the fact that a single recall is not representative of a person's habitual diet.

Interviewers may use various aids to help respondents estimate portion sizes, such as food models, photographs of different-sized portions, or household measures.

The 24-hour recall captures a highly detailed snapshot of a recent day's intake, while an FFQ is a list-based method that estimates the usual consumption of foods over a longer period, such as a year.

The 24-hour recall is valuable for large surveys because it provides high-quality data on population mean intakes and offers a relatively low burden on participants, leading to higher response rates.