# Table 2 Prediction equations to correct estimates from the food-photographic record

No. of meals Regression coefficient (b)a Intercept (a)a Correlation coefficientb (rp) R2c Corrected estimates median (IQR) % differenced after correction median (IQR)
Portion size, g 1163 0.99 0.17 0.95 0.90 93.6 (34.2, 210.7) 0.5 (−22.7, 31.1)
Energy, kcal 1163 0.95 0.29 0.95 0.90 87.0 (26.7, 203.5) −0.4 (−24.3, 29.6)
Protein, g 1163 0.92 0.17 0.93 0.87 4.2 (1.7, 9.1) 1.7 (−25.0, 35.8)
Fat, g 992 0.90 0.22 0.88 0.77 3.2 (0.9, 8.3) 1.7 (−29.4, 50.9)
Triglyceride, g 871 0.86 0.32 0.87 0.76 4.1 (1.2, 8.4) 4.1 (−28.3, 46.5)
SFA, g 966 0.94 0.20 0.91 0.83 0.8 (0.1, 2.2) 9.5 (−29.2, 56.9)
MUFA, g 928 0.91 0.16 0.91 0.82 1.1 (0.2, 3.2) 4.0 (−31.0, 53.2)
PUFA, g 962 0.85 0.02 0.90 0.80 0.9 (0.2, 2.2) 5.6 (−28.5, 55.2)
Cholesterol, mg 658 0.66 1.28 0.74 0.55 29.9 (13.9, 58.3) 2.5 (−39.0, 71.4)
Carbohydrate, g 1147 0.89 0.28 0.93 0.86 6.2 (2.6, 17.8) −0.5 (−24.9, 34.8)
Total dietary fiber, g 931 0.80 0.10 0.83 0.69 1.2 (0.6, 2.0) −0.1 (−23.8, 31.8)
Water soluble, g 849 0.77 −0.18 0.83 0.68 0.3 (0.1, 0.5) −1.8 (−26.1, 31.9)
Water insoluble, g 878 0.79 0.02 0.83 0.69 0.9 (0.4, 1.5) −3.1 (−24.1, 30.6)
Sodium, mg 1163 0.92 0.45 0.85 0.72 302.3 (173.4, 496.3) −7.1 (−30.9, 29.0)
Potassium, mg 1163 0.89 0.65 0.91 0.82 167.9 (76.1, 308.4) 2.7 (−24.0, 33.5)
Calcium, mg 1163 0.89 0.43 0.91 0.82 25.9 (11.0, 46.4) 0.6 (−24.9, 37.7)
Magnesium, mg 1154 0.87 0.39 0.88 0.77 16.7 (8.1, 28.4) −0.9 (−22.5, 29.6)
Phosphorus, mg 1163 0.91 0.41 0.91 0.83 68.5 (31.4, 127.1) 0.3 (−24.9, 32.7)
Iron, mg 1128 0.88 −0.07 0.89 0.79 0.6 (0.2, 0.9) −3.5 (−25.2, 32.0)
Zinc, mg 1154 0.91 −0.02 0.90 0.81 0.4 (0.2, 0.9) −0.2 (−26.6, 32.6)
Copper, mg 1153 0.88 − 0.34 0.91 0.82 0.06 (0.02, 0.11) −3.2 (−23.5, 28.7)
Manganese, mg 1033 0.86 −0.30 0.88 0.78 0.1 (0.03, 0.23) −1.8 (−26.6, 33.8)
Iodine, μg 777 0.46 0.27 0.50 0.25 1.9 (1.0, 3.6) −3.4 (−69.1, 137.8)
Selenium, μg 805 0.83 0.11 0.77 0.59 2.2 (1.1, 7.1) −8.6 (−39.8, 55.2)
Chromium, μg 699 0.67 −0.16 0.68 0.46 0.5 (0.3, 0.9) −5.5 (−40.4, 52.1)
Molybdenum, μg 822 0.74 0.48 0.76 0.58 6.4 (3.5, 13.5) −6.1 (−36.2, 48.5)
Retinol, μg 433 0.71 0.97 0.74 0.55 19.2 (5.1, 35.6) −5.2 (−38.0, 74.3)
α-carotene, μg 412 0.86 0.16 0.85 0.73 107.0 (2.1, 194.5) −19.3 (−49.4, 28.6)
β-carotene, μg 784 0.88 0.68 0.88 0.77 132.5 (29.1, 681.6) 3.7 (−37.9, 67.8)
Cryptoxanthin, μg 381 0.89 0.19 0.84 0.70 5.4 (2.0, 12.7) −4.8 (− 37.1, 35.6)
Vitamin D, μg 512 0.93 −0.01 0.83 0.69 0.4 (0.2, 0.9) −11.3 (−36.3, 39.4)
α-tocopherol, mg 1043 0.90 −0.07 0.89 0.79 0.4 (0.1, 0.9) 2.0 (−27.9, 40.3)
β-tocopherol, mg 544 0.84 −0.62 0.69 0.48 0.05 (0.03, 0.08) −5.6 (−40.5, 56.6)
γ-tocopherol, mg 806 0.80 −0.08 0.85 0.72 1.1 (0.2, 2.2) 7.0 (−32.2, 55.2)
δ-tocopherol, mg 565 0.83 −0.33 0.79 0.63 0.4 (0.2, 0.6) 3.7 (−37.3, 48.6)
Vitamin K, μg 900 0.85 0.43 0.88 0.77 13.7 (4.8, 28) −3.1 (−31.4, 36.6)
Vitamin B1, mg 1142 0.89 −0.24 0.89 0.79 0.05 (0.03, 0.10) 1.8 (−25.6, 42.5)
Vitamin B2, mg 1162 0.95 −0.03 0.93 0.87 0.06 (0.02, 0.14) 3.1 (−22.6, 37.1)
Niacin, mg 1162 0.90 0.04 0.92 0.84 0.8 (0.3, 2.3) 3.4 (−25.0, 39.1)
Vitamin B6, mg 1153 0.90 −0.22 0.89 0.80 0.06 (0.02, 0.15) −0.4 (−27.1, 35.0)
Vitamin B12, μg 804 0.61 −0.37 0.56 0.31 0.4 (0.3, 0.6) −15.9 (−42.3, 29.3)
Folate, μg 1135 0.85 0.51 0.89 0.79 18.5 (7.8, 32.6) 2.1 (−24.6, 40.6)
Pantothenic acid, mg 1140 0.90 −0.06 0.90 0.81 0.3 (0.1, 0.7) 1.0 (−24.6, 32.4)
Biotin, μg 831 0.84 0.14 0.78 0.60 2.3 (1.5, 3.9) −0.2 (−32.2, 54.8)
Vitamin C, mg 800 0.81 0.46 0.83 0.69 6.8 (3.3, 14.1) −4.0 (− 33.3, 51.9)
1. SFA Saturated fatty acid, MUFA Monounsaturated fatty acid, PUFA Polyunsaturated fatty acid
2. aPrediction Equation: Y = ea × (X)b, Y: directly weighed value, X: estimates based on a food-photographic record
3. bPearson’s correlation coefficient between log weighed value and estimates from a food-photographic record
4. cThe values of R2 indicate the percentage of the variance of log-Y accounted by equations
5. d(Corrected value from a food-photographic record - weighed value)/(weighed value) × 100