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Validation Information: German EPIC FFQ2

Nothlings 2007

Fitting Portion Sizes in a Self-Administered Food Frequency Questionnaire

For epidemiological studies, a simple semiquantitative FFQ was developed to assess the frequency of intake of food items demonstrated with graphically displayed portion sizes. As a validation study, a random sample of 393 participants in the European Prospective Investigation into Cancer and Nutrition (EPIC)-Potsdam Study completed 2 unannounced 24-h dietary recalls (24HDR) and the FFQ during 1 y. To calculate food and nutrient intakes, we compared the use of fitted portion sizes with the use of predefined portion sizes. Fitted portion sizes were calculated by summing food intakes over the 2 24HDR and dividing the sum by the frequency of intake reported in the FFQ for each FFQ food item, leading to similar mean intakes for FFQ and 24HDR. As predefined portion sizes, amounts that had been used in previous dietary assessments in EPIC Potsdam were used. Mean intake of 12 food groups was 102% for men or women with fitted portion sizes and 79% for men and 95% for women with predefined portion sizes of intake measured with 2 24HDR. However, deattenuated, energyadjusted correlation coefficients between FFQ and 24HDR were not better for 19 nutrients by the use of fitted portion sizes, with a mean correlation coefficient of 0.53 for men and 0.56 for women. Mean correlation coefficients for food groups also were similar for fitted and predefined portion sizes. Fitting portion sizes using recent reference data from a random sample of study participants improved the quantitative assessment of food and nutrient intake, but not ranking of study participants, compared with predefining portion sizes based on prior knowledge.

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Validation Information

Year of Publication

Tool Information

Dietary Exposure Measured
Full Nutrient, Food Groups
Tool Type
Food Frequency Questionnaire
Timeframe Tool Measures info
1 Year
Portion Size Measures info
The study compared 2 approaches in assigning portion sizes. The first was predefined portion sizes based on prior knowledge and the second was fitted portion sizes based on the 24-hour dietary recall which covered the same time period of the FFQ.
Reporting Method info
Usual; Retrospective
Format info
Supplements Measured
Not reported
Administration Method info

Study Information

Study Location
Potsdam, Germany
Associated Nutrient Database
Not reported
Comparator Validated Against
24hr Recall


Sample Size
Age of Population

Mean(SD): 59(8) years (Male); 55(10) years (Female)

Other Notable Characteristics
Participants were a part of the EPIC-Potsdam study

Total number of nutrients validated: 18 info

Not all of the nutrients validated in the validation studies are included in the table below, as statistical data was only selected to be displayed for a number of nutrients, this included:

  • Energy
  • Fat
  • Saturated Fat
  • Mono-unsaturated Fat
  • Poly-unsaturated Fat
  • Carbohydrates
  • Protein
  • Sugar
  • Non‐starch polysaccharides(NSP)
  • Sodium
  • Calcium
  • Iron
  • Zinc
  • Retinol
  • Folate
  • Folic Acid
  • Vitamin B12
  • Vitamin C
  • Fruit & Vegetables
  • Urinary Nitrogen

To find information on the other validated nutrients please read the validation study.

  • Energy
  • Macronutrients: 8
  • Micronutrients: 9
Comparator Lifestage Sex Nutrient Measured info Mean Difference Standard Deviation info Correlation Coefficient info Cohen's Kappa Coefficient Percentage Agreement Percentage Agreement Categories info Lower Limits of Agreement Upper Limits of Agreement
24hr Recall Adults Both Energy (kcal) 0.33 (P)
Energy (kcal) 0.25 (P)
Protein (g) 0.19 (P)
Protein (g) 0.19 (P)
Fat (g) 0.29 (P)
Fat (g) 0.25 (P)
Saturated Fat (g) 0.42 (P)
Saturated Fat (g) 0.29 (P)
MUFA (g) 0.24 (P)
MUFA (g) 0.26 (P)
PUFA (g) 0.15 (P)
PUFA (g) 0.18 (P)
Carbohydrates (g) 0.44 (P)
Carbohydrates (g) 0.31 (P)
Calcium (mg) 0.38 (P)
Calcium (mg) 0.47 (P)
Iron (mg) 0.27 (P)
Iron (mg) 0.20 (P)
Folic Acid (µg) 0.25 (P)
Folic Acid (µg) 0.26 (P)
Vitamin C (mg) 0.37 (P)
Vitamin C (mg) 0.24 (P)
Fruit (g) 2.7 201 0.48 (P) -392 397
Fruit (g) -2.3 187 0.41 (P) -368 364
Vegetables (g) 4.2 119 0.30 (P) -229 237
Vegetables (g) -0.3 114 0.24 (P) -225 224

Some results have been calculated using statistical techniques based on the published data.

For further information on statistical terms click on Statistical tests used in validation studies

All correlations coefficients in the table are unadjusted unless stated otherwise. For adjusted correlation coefficients and other statistical methods used in the study e.g. paired t-tests, please read the validation articles.

  • # Adjusted
  • † Energy adjusted.
  • ‡ For loge-transformed, energy-adjusted nutrient intakes.
  • ^ Adjacent included.
  • ᵟ Participants provided identical responses.
  • (w) = Weighted.

Nothlings U, Hoffmann K, Bergmann MM, Boeing H. Fitting portion sizes in a self-administered food frequency questionnaire. The Journal of nutrition. 2007;137(12):2781-6. Food Frequency Questionnaire.The Journal of Nutrition, 137:2781-2786.