Consumption Log Method

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Consumption log methods are used for direct consumption documentation , in which the food and quantities consumed are continuously logged in consumption logs over a specified period of time. In the case of the food record methods, a distinction is made between weighing and estimation protocol methods. They serve the nutritional anamnesis .

Survey forms

With the direct method, a distinction is made between the prospective and the retrospective method. With the prospective method one records the current consumption of food in consumption log booklets. Retrospective methods are used to describe eating habits from the past, e.g. B. from the previous day, the last week or the last month. They are recorded with the help of consumption frequency questionnaires or 24-hour reminder protocols.

Collection problems

The consumption documentation requires the cooperative participation of the test persons. For most of the test subjects, the decisive factors for the willingness to cooperate are the amount of time required and the workload of the documentation. If the test persons record the food they have eaten over a longer period of time, this can lead to the test persons changing their habitual food consumption unconsciously or consciously. The longer the survey, the greater the change. In this case, depending on the situation, test persons eat less or forget or do not write down all the foods they eat. In order to describe the consumption habits, a consumption log is often carried out over seven days. The log should include working days and weekend days, as eating habits during the week are often different from those on weekends. If you want to record the eating habits of a group ( sample ), the test subjects' protocols should begin on different days of the week. This can be used to prevent changes in consumption information or the description of the eating habits of a group from being falsified, because experience has shown that consumption has not been precisely recorded on the last few days.

Quality problems

Information from nutrition logs can lead to various false conclusions due to problems during the survey phase, which falsify the picture of the surveyed eating habits.

Lack of cooperation

Insufficient willingness to cooperate can distort the picture of eating habits. If the willingness to cooperate falls above average within a sample, the result of the sample can no longer be transferred to the population of the group to be examined. The result is no longer representative .

Changed eating habits

Changes in the recording of consumption habits also have an effect. Unconsciously or consciously changing the consumption quantities or the food consumed leads to a bias in the sample. These unconscious or conscious changes in the logs are mainly due to an underestimation of the amount of food actually consumed.

Long and short protocol phases

The length of the protocol phase can change eating habits. Long protocol phases show a lower variation in the average food consumption than shorter ones, because days with a coincidentally higher food consumption offset days with a low food consumption. Short protocol phases, on the other hand, lead to higher variations. This means that larger or smaller amounts of certain foods consumed by chance influence the picture of eating habits and lead to overestimations in the assessment .

Prospective direct method

In the prospective direct method, weighing logs and estimation logs or a mixture of both are often used for nutritional surveys. A third method, the double-serving technique, in which meals are analyzed for nutrients in the laboratory, is only used for scientific and experimental investigations. It is not explained in more detail below.

Weighing report

In the weighing protocol, all foods are weighed (in grams ) before consumption . Leftovers are also weighed. Weighing leads i. d. Usually not the test person, but trained examination staff. This ensures that the actual amount consumed is recorded.

With the weighing protocol you want to collect very precise data. The examining staff must be trained and the subjects must be instructed precisely. The burden of the examination is therefore generally very high, as is the personnel expenditure, which means that the financial expenditure is also high. Due to the high stress on the subjects, high failure rates must be expected. Therefore, subjects who tend to be more nutrition and health-conscious remain in the study group. As a result, the representativeness of the investigation suffers. Another problem is the food offered. Due to the constant weighing, food that is easy to prepare is often consumed. At the same time, the constant presence of the examining staff often influences the eating habits of the test subjects. It is also difficult to record out-of-home consumption. Conclusion: Weighing reports alone are unsuitable for representative surveys. They are often used for a short period of time and are best suited for small groups in clinical or experimental studies with highly motivated study participants.

Estimation protocol

Similar to weighing logs, estimation logs record the consumption of food over a defined period of time. The consumption quantities are not weighed, but estimated by the test persons. They use common household dimensions such as cup, tablespoon, plate, etc. for logging. a .; The study participants are instructed in this by trained examination personnel before the start of the examination. But the test subjects should also be supervised and monitored during the survey phase. It supports complete and reliable record keeping. Estimation protocols such as weighing protocols demand a high degree of willingness to cooperate from the test persons. You need to make sure to take notes immediately after meals, recording all foods consumed and maintaining eating habits during the survey phase. After the survey, the examining staff recorded the recorded food with the help of computer programs. A nutrient database such as the Federal Food Code (BLS) is often used to calculate the nutrient uptake ( nutritional value analysis). Conclusion: Estimation protocols are i. d. Usually guided by test persons themselves. The test persons must be trained to keep the minutes before the survey and they must also be instructed and monitored during the survey phase. The estimation protocols can be used to record the food consumption of large population groups and to collect representative data based on the samples. Estimation protocols are also used for nutritional history of individuals, e.g. B. in nutritional advice. Powerful analysis programs are also available for this.

Retrospective direct method

With the retrospective method, nutritional information on consumption is collected several hours, days or months after the meal. The primary aim of choosing these survey methods is to collect information about the choice and consumption of food. Portion sizes can also be requested.

24-hour reminder protocol

In the 24-hour nutrition protocol, a trained interviewer asks questions about the type and amount of food consumed the day before. The interviewer uses a structured interview for this . The quantities given are estimated according to normal household measurements. The burden on the test person is low. The eating habits are not influenced and the willingness to participate is higher than with prospective methods. Conclusion: A 24-hour nutrition protocol has a low level of stress for the test subject. The information content depends to a large extent on the subject's ability to remember. The amounts consumed are often underestimated by those who eat well and are more likely to be overestimated by those who eat little. Due to the high number of participants, the method can be used to collect representative data, e.g. B. the National Health and Nutrition Examination Survey (NHANES-II study).

Consumption Frequency Log

In the consumption frequency questionnaire, the frequency of consumption of certain foods is asked by trained interviewers. The questionnaire can also be sent to the test subjects, who then fill it in themselves. Conversely, this method serves as a food-based model for nutritional recommendations in the form of nutrition pyramids. It is used to record food consumption over a period of several days, weeks or months. This requires good memory from the participants. It is also possible that the ability to remember past eating habits is disproportionately influenced by current eating habits. Food intake is often overestimated. Nevertheless, the number of participants is low even with this survey method. Conclusion: A consumption frequency questionnaire is always used if you want to examine eating habits over a longer period of time. Often one wants to investigate the connection between the frequency of consumption and the occurrence of certain diseases.

Individual evidence

  1. ^ German Nutrition Society: Nutrition Report 2008 . DGE, Bonn, 2008, p. 38ff, ISBN 978-3-88749-214-4
  2. ↑ Linda Friedrich: The pocket PC with barcode scanner in the nutrition survey: conception and use of a pocket PC-supported consumption survey for 9 to 11 year olds. Kovač Verlag, Hamburg, 2009, ISBN 978-3-8300-4311-9
  3. ↑ Thomas Ellrott : New methods for recording consumption . Nutritional review 07/02, B25-B28.
  4. ↑ Heike Schick-Biedermann: DGE-PC professional , DGEInfo 11/2004
  5. ↑ Roma Beitz: Diet and health related aspects of vitamin and mineral supplement use in Germany. Cuvillier, Göttingen, 2003, ISBN 3-89873-945-7
  6. ↑ Heiner Boeing: Food-based prevention concepts. Nutritional review 08/09, PDF

Reading list

  • Jürgen Bortz, Nicola Döring: Research methods and evaluation for human and social scientists . 3rd, completely revised and updated edition, Springer, Berlin; Heidelberg; Singapore; Tokyo; New York; Barcelona; Budapest; Hong Kong; London; Milan; Paris; Santa Clara, 2003, ISBN 3-540-59375-6
  • Roland Schneider: On dealing with numbers and data: a practical introduction to statistics and nutritional epidemiology . Umschau-Zeitschr.-Verl., Frankfurt am Main, 1997, ISBN 3-930007-06-1

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