Food Frequency Questionnaire (FFQ-120)

Overview

The Food Frequency Questionnaire (FFQ-120) is a comprehensive self-administered dietary assessment instrument designed to evaluate an individual’s habitual food and beverage consumption over the previous 12 months. Comprising 120 food and beverage items, the questionnaire captures long-term dietary intake by recording the frequency with which commonly consumed foods are eaten. The FFQ-120 includes foods representative of the Mediterranean and Greek dietary pattern, making it particularly suitable for nutritional epidemiology and public health research conducted within Mediterranean populations.

Unlike short-term dietary assessment methods, the FFQ-120 estimates usual dietary intake, allowing researchers to investigate long-term nutritional habits and their associations with chronic disease risk, nutritional status, and health outcomes. Owing to its practicality, relatively low participant burden, and ability to capture habitual dietary behaviors, the FFQ-120 has become one of the most widely used dietary assessment tools in nutritional epidemiology, preventive medicine, public health, clinical nutrition, and chronic disease research.

Objective

The primary objective of the Food Frequency Questionnaire (FFQ-120) is to provide a comprehensive quantitative assessment of habitual dietary intake, enabling researchers and healthcare professionals to evaluate food consumption patterns and adherence to healthy dietary recommendations.

More specifically, the FFQ-120 is designed to:

  • Assess the habitual consumption frequency of major food groups over the previous year.
  • Evaluate adherence to dietary patterns, including the Mediterranean diet.
  • Estimate energy intake and macro- and micronutrient consumption.
  • Investigate associations between dietary habits and chronic disease risk.
  • Support nutritional surveillance, dietary intervention studies, and public health policy development.
  • Facilitate epidemiological research examining relationships between nutrition and health outcomes.

Scale Structure

The FFQ-120 consists of 120 food and beverage items covering the principal components of the Mediterranean dietary pattern. Participants report how frequently they consume each food using an 8-category frequency response scale:

  • Never or almost never
  • 1–3 times per month
  • Once per week
  • 2–4 times per week
  • 5–6 times per week
  • Once per day
  • 2–3 times per day
  • 4 or more times per day

The questionnaire includes foods from all major dietary groups, including:

  • Fruits
  • Vegetables
  • Cereals and whole grains
  • Legumes
  • Dairy products
  • Meat and processed meat
  • Poultry
  • Fish and seafood
  • Eggs
  • Olive oil and other fats
  • Nuts and seeds
  • Sweets and desserts
  • Non-alcoholic beverages
  • Alcoholic beverages

Consumption frequencies are subsequently converted into standardized estimates of average daily or weekly intake using predefined portion sizes.

Applications

The Food Frequency Questionnaire (FFQ-120) is extensively used in nutritional epidemiology, clinical nutrition, preventive medicine, public health, endocrinology, cardiology, oncology, gastroenterology, and population health research. It is appropriate for adolescents, adults, older adults, and large community-based cohorts, where the assessment of long-term dietary habits is required.

The FFQ-120 has been widely employed to investigate relationships between dietary patterns and numerous health outcomes, including cardiovascular disease, obesity, type 2 diabetes mellitus, metabolic syndrome, hypertension, cancer, osteoporosis, cognitive decline, gastrointestinal disorders, and overall mortality. In clinical practice, it assists dietitians and healthcare professionals in identifying dietary deficiencies, monitoring nutritional interventions, and evaluating compliance with dietary recommendations. Furthermore, the questionnaire serves as a fundamental tool in longitudinal cohort studies, intervention trials, and national nutrition surveillance programs aimed at evaluating population dietary behaviors and informing evidence-based public health policies.

Scoring and Psychometric Evaluation

Responses are converted into estimated daily or weekly food consumption frequencies, which are subsequently combined with standardized portion sizes to estimate average food intake. Nutritional analysis software or validated dietary algorithms are then used to calculate total daily energy intake, macronutrient consumption (carbohydrates, proteins, and fats), and micronutrient intake, including vitamins, minerals, and dietary fiber.

Foods are categorized into major dietary groups, enabling calculation of composite dietary quality indices such as the Mediterranean Diet Score (MDS), Healthy Eating Index (HEI), and other dietary pattern scores commonly used in nutritional epidemiology. These dietary indicators may subsequently be incorporated into regression analyses, survival analyses, and other statistical models to examine associations with anthropometric measurements, biochemical markers, chronic disease incidence, and health-related outcomes.

Psychometric evaluation of the FFQ-120 typically involves assessment of reproducibility, relative validity, and measurement agreement by comparing questionnaire responses with reference dietary assessment methods, including repeated 24-hour dietary recalls, 3- or 7-day food diaries, and objective biomarkers of dietary intake, such as circulating vitamin concentrations or plasma fatty acid profiles. Statistical validation commonly includes Pearson or Spearman correlation coefficients, intraclass correlation coefficients (ICC), repeatability analyses, and Bland–Altman plots to evaluate agreement between methods. These procedures ensure that the questionnaire provides reliable estimates of habitual dietary intake suitable for epidemiological and clinical research.

Interpretation

Higher reported consumption frequencies reflect greater habitual intake of the corresponding food items or food groups. Interpretation focuses primarily on overall dietary patterns rather than isolated food items, allowing researchers to identify healthy or unhealthy eating behaviors. Greater consumption of fruits, vegetables, legumes, whole grains, fish, and olive oil is generally indicative of stronger adherence to the Mediterranean dietary pattern, which has consistently been associated with lower risks of cardiovascular disease, metabolic disorders, several cancers, cognitive decline, and all-cause mortality. Conversely, frequent consumption of processed meats, refined grains, sugar-sweetened beverages, and energy-dense processed foods may indicate dietary patterns associated with increased cardiometabolic risk.

The FFQ-120 provides a comprehensive representation of long-term dietary behavior and is particularly valuable when examining nutrition as a determinant of chronic disease and population health.

References

Katsouyanni, K., et al. (1997). European Prospective Investigation into Cancer and Nutrition (EPIC): Validity and reproducibility of a food frequency questionnaire in a Greek population. Public Health Nutrition, 1(1), 47–58.

Willett, W., Sampson, L., Stampfer, M. J., et al. (1985). Reproducibility and validity of a semiquantitative food frequency questionnaire. American Journal of Epidemiology, 122(1), 51–65.

Trichopoulou, A., Costacou, T., Bamia, C., & Trichopoulos, D. (2003). Adherence to a Mediterranean diet and survival in a Greek population. New England Journal of Medicine, 348(26), 2599–2608.

Cade, J. E., Thompson, R. L., Burley, V. J., & Warm, D. L. (2002). Development, validation and utilisation of food-frequency questionnaires: A review. Public Health Nutrition, 5(4), 567–587.