What is the 24-Hour Dietary Recall?

By Malik Tiedt, BSPH Student in Nutrition

“What did you eat yesterday?”

It seems like an easy question. You may have had a meal at a restaurant, leftovers, or maybe just a snack in passing. 

“When did you eat yesterday?”

Identifying a vague time period may seem remedial, but how precise can you pinpoint when you ate? Do you remember what you were doing – were you watching TV or scrolling through your phone?

“How much did you eat yesterday?”

Somehow, asking about more specific details makes your answer entirely more complex. What did the portion size look like? How much did you drink? Did you have more than one serving?

The list of questions goes on, prompting thoughts about who you ate meals with, how the food was prepared, and the different types of food (fruits, vegetables, grains) each meal contained. These questions are the backbone of the 24-hour dietary recall: an assessment of nutritional intake widely used in clinical nutrition, epidemiology, and public health. 

What is the 24-Hour Dietary Recall?

The 24-hour dietary recall is a structured interview that collects information about short-term dietary tendencies. These recalls may be conducted by a practitioner (primary care provider or registered dietitian) when a patient is either seeking advice about their dietary behaviors or participating in research. The interview contains open-ended and non-leading questions that capture information about the foods, beverages, supplements, portion sizes, and consumption patterns over the past twenty-four hours. It is generally administered by a trained interviewer, but automated self-reporting programs are becoming common.

This dietary recall assessment typically lasts from 20 to 60 minutes. It starts with general questions about what participants have eaten over the last twenty-four hours. They are then encouraged to recall more specific details about their meals, like portion sizes and preparation. Interviewers may use images and portion models to assist participants in recalling additional, accurate information about their consumption patterns. The researchers then quantify participants’ food intake by analyzing their reports for nutrients and evaluating relations between nutrients and health outcomes, such as the prevalence or incidence of disease. 

Why is the  24-Hour Dietary Recall useful?

The National Cancer Institute’s Dietary Assessment Primer offers a comparison of multiple instruments used to measure dietary quality, including 24-hour dietary recalls, food records or diaries, food frequency questionnaires, and food screener profiles. 

Unlike other methods, the 24-hour dietary recall is focused on collecting information about participants’ short-term diet rather than long-term consumption. This can be advantageous as data can be used to provide detailed information about what people ate and drank on a particular day, or what they do while eating. 

Limitations of the 24-Hour Dietary Recall

It is debated whether this method can reliably describe how nutrient intake is tied to health outcomes. One potential problem is that our dietary choices change on a day to day basis. Another is that an interviewee may simply not remember what they ate. The multi-pass format attempts to address this memory issue by giving respondents several opportunities to remember the types and portions of food they consumed the previous day. Conducting several interviews may also help collect more reliable data. 

Another thing that can go wrong is that respondents may feel pressured to alter what and how often they eat if they are aware of an upcoming 24-hour dietary recall assessment. For instance, they may feel pressured to under-report “bad” foods and overreport “good” foods. If you knew that someone was going to be asking about your dietary intake tomorrow, would you elect to eat ice cream tonight, or would you choose vegetables to avoid judgment?

The 24-hour dietary recall is widely utilized in the world of both research and clinical settings, and helps practitioners gain a complete picture of the types of foods their patients may be consuming. However, clinical findings and studies relying on this method to collect data should be perceived through a critical lens due to the limitations of day-to-day dietary variations and issues participants may have with memory. 

Peer-edited by Anastasia Yandulskaya, PhD Candidate in Cell and Molecular Biology

Picture credit: iStock