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. 2021 May 12;13(5):1629. doi: 10.3390/nu13051629

Table 2.

Test–retest reliability of the food frequency questionnaire (n = 150).

Food Groups 1 (g) ICC 2 95% CI
Cereals 0.26 0.11–0.41
Legumes 0.55 0.42–0.65
Vegetables 0.71 0.62–0.78
Fruits 0.53 0.41–0.64
Nuts 0.51 0.37–0.63
Dairy products 0.67 0.57–0.75
Fish 0.62 0.51–0.71
Meat 0.58 0.46–0.68
Processed meat 0.63 0.52–0.72
Olive oil 0.54 0.41–0.64
Animal fat 0.62 0.43–0.76
Baked goods 0.36 0.21–0.50
Nutrients 1 (units) ICC 95% CI
Energy (kcal) 0.57 0.45–0.67
Carbohydrates (g) 0.58 0.46–0.68
Proteins (g) 0.62 0.51–0.71
Fat (g) 0.50 0.54–0.76
Saturated FA (g) 0.51 0.38–0.77
Monounsaturated FA (g) 0.48 0.35–0.59
Polyunsaturated FA (g) 0.49 0.36–0.60
Cholesterol (mg) 0.66 0.55–0.74
Fiber (g) 0.68 0.59–0.76
Potassium (mg) 0.67 0.57–0.75
Calcium (mg) 0.61 0.50–0.70
Vitamin C (mg) 0.62 0.51–0.71
Vitamin A (mcg) 0.76 0.68–0.82
Vitamin E (mg) 0.59 0.47–0.68
Niacin (mg) 0.62 0.51–0.71
Folic acid (mcg) 0.70 0.60–0.77
Vitamin B12 (mcg) 0.68 0.59–0.76
Score (units) ICC 95% CI
MedDiet score 0.53 0.40–0.63

ICC = intraclass correlation coefficient; CI = confidence interval; FA = fatty acids; MedDiet = Mediterranean diet.1 Variables were log-transformed with the exception of energy and the MedDiet score.2 p < 0.01 for all.