Table 3.
Empirical results of the first-difference model; nationally representative sample of the US population (n 7647)
| Energy (kJ) | Fibre (g) | Na (mg) | |||||||
|---|---|---|---|---|---|---|---|---|---|
| β | se | P | β | se | P | β | se | P | |
| Food amount (g) | 236·84 | 7·18 | 0·00 | −0·05 | 0·01 | 0·00 | −8·02 | 2·03 | 0·00 |
| Dark green/orange vegetables – home (cups) | 332·84 | 117·26 | 0·01 | 1·38 | 0·26 | 0·00 | −55·80 | 28·49 | 0·07 |
| Dark green/orange vegetables – away (cups) | 124·06 | 337·17 | 0·72 | 1·07 | 0·32 | 0·01 | 186·24 | 125·75 | 0·16 |
| Potatoes – home (cups) | 366·70 | 86·56 | 0·00 | 0·30 | 0·08 | 0·00 | −52·03 | 23·12 | 0·04 |
| Potatoes – away (cups) | 665·35 | 157·61 | 0·00 | 0·08 | 0·10 | 0·43 | −75·77 | 35·24 | 0·05 |
| Tomatoes – home (cups) | 245·64 | 117·05 | 0·05 | 0·86 | 0·09 | 0·00 | 178·88 | 18·16 | 0·00 |
| Tomatoes – away (cups) | 1521·76 | 159·19 | 0·00 | 0·25 | 0·29 | 0·40 | 113·28 | 45·72 | 0·03 |
| Other vegetables – home (cups) | 67·74 | 93·78 | 0·48 | 1·14 | 0·07 | 0·00 | 74·71 | 17·58 | 0·00 |
| Other vegetables – away (cups) | 99·33 | 102·22 | 0·35 | 0·49 | 0·12 | 0·00 | 91·30 | 28·59 | 0·01 |
| Weekend | 285·28 | 134·90 | 0·05 | −0·66 | 0·19 | 0·00 | −25·04 | 21·21 | 0·26 |
| Constant | −65·16 | 65·56 | 0·34 | 0·41 | 0·08 | 0·00 | 65·35 | 15·87 | 0·00 |
| R 2 | 0·47 | 0·11 | 0.06 | ||||||
Source: National Health and Nutrition Examination Survey 2003–2004.