Table 2.
Comparison of energy and nutrient intake estimates from the Remote Food Photography Method (RFPM) and two gold standards: 1) energy intake measured by doubly labeled water in free-living conditions, and 2) energy and nutrient intake measured in laboratory-based buffet meals.
| EI measured with the RFPM | EI measured with the gold standard | Difference | p-value | Mean participant error (%) | |
|---|---|---|---|---|---|
| Study 1a | |||||
| Standard Prompts (n = 22) | 1570 ± 636 | 2465 ± 557 | −895 ± 770 | <.0001 | −34.3 ± 28.2 |
| Customized Prompts (n = 13) | 1907 ± 536 | 2177 ± 491 | −270 ± 748 | 0.22 | −8.8 ± 29.8 |
| Study 2 | |||||
| Free-living (n = 42)a | 2208 ± 665 | 2360 ± 626 | −152 ± 694 | 0.16 | −3.7 ± 28.7 |
| Buffet Meals (n = 49) | |||||
| Energy (kcal) | 583 ± 190 | 587 ± 209 | −4 ± 73 | 0.67 | 1.2 ± 15.1 |
| Fat (kcal) | 143 ± 57 | 136 ± 60 | 7 ± 19 | 0.02 | 8.7 ± 19.8 |
| Carbohydrate (kcal) | 350 ± 124 | 367 ± 136 | −17 ± 55 | 0.04 | −3.2 ± 18.3 |
| Protein (kcal) | 98 ± 27 | 92 ± 29 | 6 ± 17 | 0.03 | 10.0 ± 23.9 |
| Vitamin A (mcg) | 91 ± 36 | 78 ± 34 | 13 ± 17 | <.0001 | 22.9 ± 31.9 |
| Vitamin C (mg) | 7 ± 3 | 6 ± 2 | 1 ± 2 | 0.02 | 17.3 ± 38.4 |
| Calcium (mg) | 246 ± 73 | 236 ± 73 | 10 ± 43 | 0.11 | 6.9 ± 20.7 |
| Iron (mg) | 5 ± 2 | 5 ± 2 | 0 ± 1 | 0.23 | 3.3 ± 14.6 |
| Sodium (mg) | 1315 ± 353 | 1331 ± 431 | −15 ± 237 | 0.65 | 2.6 ± 20.8 |
| Cholesterol (mg) | 48 ± 15 | 39 ± 14 | 9 ± 11 | <.0001 | 30.1 ± 41.2 |
| Fiber (g) | 4 ± 1 | 4 ± 1 | 0 ± 0 | 0.95 | 0.9 ± 13.1 |
Notes: Food intake values reflect mean ± SD. P-values in bold text were statistically significant (alpha was set at 0.01 for the buffet meal comparisons from the main study and all other comparisons relied on alpha equal to 0.05).
a
Doubly labeled water was used as the gold standard in Study 1 and for free-living comparisons in Study 2. Energy intake in these comparisons reflects kcal/day.