TABLE 2.
Mean true and reported portion sizes and differences, mean ratio of amount reported to amount eaten, and proportion of reported portion sizes within 10% and 25% of truth for foods and drinks for which a match was reported, by recall mode, ASA24 and AMPM1
| ASA24 |
AMPM |
|||||||||||||
| Observations, n | Mean amount eaten, g | Mean amount reported, g | Difference,2 g | Ratio of amount reported to amount eaten | Within 10% of truth, % | Within 25% of truth, % | Observations, n | Mean amount eaten, g | Mean amount reported, g | Difference,2 g | Ratio of amount reported to amount eaten | Within 10% of truth, % | Within 25% of truth, % | |
| All foods and drinks | 801 | 104 | 108 | 3.68 (−3.76, 11.1) | 0.977 (0.896, 1.06) | 16.2 | 37.5 | 900 | 90 | 102 | 11.8 (5.75, 17.9) | 1.17 (1.09, 1.25) | 14.9 | 33.2 |
| All foods excluding liquids | 637 | 62.9 | 69.8 | 6.85 (0.471, 13.2) | 0.98 (0.892, 1.08) | 14.4 | 35.5 | 731 | 60.1 | 73.4 | 13.4 (7.99, 18.8) | 1.21 (1.12, 1.3) | 15.0 | 32.7 |
| Liquids | 164 | 264 | 255 | −8.66 (−33.7, 16.4) | 0.963 (0.839, 1.10) | 23.2 | 45.1 | 169 | 219 | 225 | 5.13 (−14.7, 24.9) | 1.00 (0.902, 1.11) | 14.2 | 35.5 |
| Amorphous or soft | 303 | 66.1 | 80.5 | 14.4 (5.07, 23.8) | 0.964 (0.859, 1.08) | 7.92 | 28.4 | 338 | 62.8 | 83.7 | 20.9 (12.5, 29.3) | 1.20 (1.09, 1.33) | 12.4 | 32.8 |
| Single unit | 192 | 74.5 | 73.1 | −1.42 (−8.26, 5.43) | 1.02 (0.929, 1.12) | 26.6 | 53.1 | 209 | 72.4 | 70.9 | −1.48 (−6.03, 3.06) | 1.04 (0.956, 1.13) | 22.5 | 44.0 |
| Small pieces | 60 | 17.9 | 21.8 | 3.89 (−3.22, 11) | 1.17 (0.837, 1.65) | 6.67 | 16.7 | 83 | 18.3 | 40.1 | 21.8 (11.7, 31.9) | 1.97 (1.61, 2.41) | 8.43 | 14.5 |
| Shaped foods | 47 | 94.3 | 95.5 | 1.22 (−15.7, 18.1) | 0.887 (0.753, 1.05) | 17.0 | 34.0 | 65 | 85.9 | 103 | 17.4 (0.989, 33.8) | 1.08 (0.856, 1.36) | 13.8 | 20.0 |
| Spreads | 35 | 7.61 | 6.97 | −0.639 (−2.36, 1.08) | 0.764 (0.596, 0.98) | 14.3 | 34.3 | 36 | 12.1 | 14.7 | 2.59 (−2.38, 7.57) | 1.24 (0.918, 1.67) | 13.9 | 30.6 |
1
Values are means (95% CIs) unless otherwise indicated. ASA24, n = 40 individuals and 801 observations; AMPM, n = 41 individuals and 900 observations. AMPM, Automated Multiple-Pass Method; ASA24, Automated Self-Administered 24-hour.
2
Expressed as reported minus true portion size. Thus, positive differences are indicative of overestimation and negative differences are indicative of underestimation of portion size.