# Abstract

 

## Background Web-based, computer-tailored nutrition education interventions can be effective in modifying self-reported dietary behaviors. Traditional computer-tailored programs primarily targeted individual cognitions (knowledge, awareness, attitude, self-efficacy). Tailoring on additional variables such as self-regulation processes and environmental-level factors (the home food environment arrangement and perception of availability and prices of healthy food products in supermarkets) may improve efficacy and effect sizes (ES) of Web-based computer-tailored nutrition education interventions. 

## Objective This study evaluated the short- and medium-term efficacy and educational differences in efficacy of a cognitive and environmental feedback version of a Web-based computer-tailored nutrition education intervention on self-reported fruit, vegetable, high-energy snack, and saturated fat intake compared to generic nutrition information in the total sample and among participants who did not comply with dietary guidelines (the risk groups). 

## Methods A randomized controlled trial was conducted with a basic (tailored intervention targeting individual cognition and self-regulation processes; n=456), plus (basic intervention additionally targeting environmental-level factors; n=459), and control (generic nutrition information; n=434) group. Participants were recruited from the general population and randomly assigned to a study group. Self-reported fruit, vegetable, high-energy snack, and saturated fat intake were assessed at baseline and at 1- (T1) and 4-months (T2) postintervention using online questionnaires. Linear mixed model analyses examined group differences in change over time. Educational differences were examined with group×time×education interaction terms. 

## Results In the total sample, the basic (T1: ES=--0.30; T2: ES=--0.18) and plus intervention groups (T1: ES=--0.29; T2: ES=--0.27) had larger decreases in high-energy snack intake than the control group. The basic version resulted in a larger decrease in saturated fat intake than the control intervention (T1: ES=--0.19; T2: ES=--0.17). In the risk groups, the basic version caused larger decreases in fat (T1: ES=--0.28; T2: ES=--0.28) and high-energy snack intake (T1: ES=--0.34; T2: ES=--0.20) than the control intervention. The plus version resulted in a larger increase in fruit (T1: ES=0.25; T2: ES=0.37) and a larger decrease in high-energy snack intake (T1: ES=--0.38; T2: ES=--0.32) than the control intervention. For high-energy snack intake, educational differences were found. Stratified analyses showed that the plus version was most effective for high-educated participants. 

## Conclusions Both intervention versions were more effective in improving some of the self-reported dietary behaviors than generic nutrition information, especially in the risk groups, among both higher- and lower-educated participants. For fruit intake, only the plus version was more effective than providing generic nutrition information. Although feasible, incorporating environmental-level information is time-consuming. Therefore, the basic version may be more feasible for further implementation, although inclusion of feedback on the arrangement of the home food environment and on availability and prices may be considered for fruit and, for high-educated people, for high-energy snack intake. 

## Trial Registration Netherlands Trial Registry NTR3396; http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=3396 (Archived by WebCite at http://www.webcitation.org/6VNZbdL6w). # Results 

## Participant Characteristics at Baseline A total of 1349 participants were included in the analyses. The mean age of the participants was 49.05 years (SD 10.62), 35.43% (478/1349) were male, 1.34% (18/1348) had a non-Western ethnic background, and 45.66% (616/1349) were in the high-educated group ([Table 1](#)). The mean daily vegetable intake was 159.12 grams (SD 69.24), daily fruit intake was 1.85 pieces (SD 1.29), daily high-energy snack intake was 3.34 pieces (SD 2.98), and mean saturated fat intake was 17.91 fat points (SD 6.07). The sizes of the risk groups were as follows: 1014 participants (75.17%) did not comply with the recommendation of 200 grams of vegetables a day, 803 participants (59.53%) did not comply with the guideline of 2 pieces of fruit per day, 808 participants (59.90%) consumed more than 2 high-energy snacks per day, and 627 participants (46.48%) did not comply with the age- and gender-specific guidelines for maximum fat intake. The plus group was significantly younger than the control group (OR 0.99, 95% CI 0.97-0.99, *P*=.04) and the plus group consisted of more lower-educated people than the basic group (OR 1.33, 95% CI 1.01-1.74, *P*=.04). Hence, age and education were included in the repeated measures analyses as covariates in addition to place of residence. ::::table-wrap

::: caption
Participant characteristics at baseline.
:::

______________________________________________________________________

Characteristic Total Control Basic Plus Group comparison, OR (95% CI)^a^\
n=1349 n=434 n=459 n=456

______________________________________________________________________

Basic vs control Plus vs control Plus vs basic

**Background characteristics**

```
                              Age (years), mean (SD)                                          49.05 (10.62)          50.01 (10.40)    48.63 (11.10)    48.54 (10.30)                      0.99 (0.98, 1.00)   0.99 (0.97, 0.99)   0.99 (0.99, 1.01)   

                              **Gender, n (%)**                                                                                                                                                                                                

                                                                                             Male                   478 (35.43)      145 (33.4)       165 (36.2)                         168 (36.6)          1.00                1.00                1.00

                                                                                             Female                 871 (64.57)      289 (66.6)       291 (63.8)                         291 (63.4)          0.80 (0.60, 1.08)   0.80 (0.59, 1.07)   1.00 (0.75, 1.34)

                              **Ethnicity (n=1348), n (%)**                                                                                                                                                                                      

                                                                                             Western                1330 (98.66)     425 (98.2)       451 (98.9)                         454 (98.9)          1.00                1.00                1.00

                                                                                             Non-Western            18 (1.34)        8 (1.8)          5 (1.1)                            5 (1.1)             0.50 (0.16, 1.60)   0.49 (0.16, 1.55)   0.98 (0.28, 3.44)

                              **Educational level, n (%)**                                                                                                                                                                                        

                                                                                             High                   616 (45.66)      184 (42.4)       232 (50.9)                         200 (43.6)          1.00                1.00                1.00

                                                                                             Lower                  733 (54.34)      250 (57.6)       224 (49.1)                         259 (56.4)          0.77 (0.58, 1.01)   1.02 (0.77, 1.34)   1.33 (1.01, 1.74)

                              **Place of residence (ie, cities in the Netherlands), n (%)**                                                                                                                                                        

                                                                                             Heerlen                323 (23.94)      103 (23.7)       113 (24.8)                         107 (23.3)          1.00                1.00                1.00

                                                                                             Roermond               217 (16.09)      69 (15.9)        78 (17.1)                          70 (15.3)           1.04 (0.68, 1.59)   1.00 (0.65, 1.54)   0.95 (0.62, 1.44)

                                                                                             Weert                  251 (18.60)      77 (17.7)        82 (18.0)                          92 (20.0)           1.01 (0.67, 1.54)   1.19 (0.79, 1.79)   1.17 (0.79, 1.75)

                                                                                             Venlo                  304 (22.54)      104 (24.0)       93 (20.4)                          107 (23.3)          0.82 (0.56, 1.22)   1.01 (0.69, 1.49)   1.23 (0.83, 1.81)

                                                                                             Venray                 254 (18.83)      81 (18.7)        90 (19.7)                          83 (18.1)           1.05 (0.70, 1.59)   1.04 (0.68, 1.57)   0.98 (0.65, 1.46)
```

**Dietary intake**

```
                              **Vegetable intake (grams)**                                                                                                                                                                                       

                                                                                             Mean (SD)              159.12 (69.24)   157.73 (64.54)   162.68 (72.76)                     156.91 (69.94)      1.00 (0.99, 1.00)   1.00 (0.99, 1.00)   1.00 (0.99, 1.00)

                                                                                             Not complying, n (%)   1014 (75.17)     330 (76.0)       338 (74.1)                         346 (75.4)                                                

                              **Fruit intake (pieces)**                                                                                                                                                                                           

                                                                                             Mean (SD)              1.85 (1.29)      1.80 (1.23)      1.92 (1.36)                        1.81 (1.27)         1.07 (0.97, 1.20)   1.03 (0.92, 1.15)   0.95 (0.85, 1.05)

                                                                                             Not complying, n (%)   803 (59.53)      261 (60.1)       263 (57.7)                         279 (60.8)                                                

                              **High-energy snack intake (pieces)**                                                                                                                                                                              

                                                                                             Mean (SD)              3.34 (2.98)      3.19 (2.74)      3.30 (2.94)                        3.51 (3.24)         1.04 (0.98, 1.10)   1.05 (0.99, 1.11)   1.02 (0.96, 1.07)

                                                                                             Not complying, n (%)   808 (59.90)      251 (57.8)       275 (60.3)                         282 (61.4)                                                

                              **Saturated fat intake (fat points) (n=1348)**                                                                                                                                                                      

                                                                                             Mean (SD)              17.91 (6.07)     17.99 (6.07)     17.60 (6.09)                       18.13 (6.05)        0.98 (0.96, 1.01)   0.99 (0.96, 1.02)   1.01 (0.98, 1.04)

                                                                                             Not complying, n (%)   627 (46.47)      197 (45.4)       203 (44.5)                         227 (49.5)                                                
```

______________________________________________________________________

^a^ Logistic regression model with age, gender, ethnicity, educational
level, place of residence, fruit intake, vegetable intake, high-energy
snack intake, and fat intake as independent variables.:::: 

## Loss to Follow-Up A total of 1349 participants filled out the baseline questionnaire, 902 participants filled out the complete first follow-up questionnaire (33.14% dropout), and 766 participants completely filled out the second follow-up questionnaire (43.22% dropout) ([Figure 2](#)). Younger participants were more likely to drop out between baseline and T1 (OR 1.02, 95% CI 1.01-1.03, *P*=.002) and T2 (OR 1.03, 95% CI 1.02-1.04, *P*\<.001) compared to older participants. Dropout between baseline and T1 was higher in the basic (34.6%, 158/456; OR 1.42, 95% CI 1.07-1.90, *P*=.02) and the plus group (37.3%, 171/459; OR 1.55, 95% CI 1.17-2.07, *P*=.003) than in the control group (27.2%, 118/434). Dropout between baseline and T2 was also higher in the basic (44.3%, 202/456; OR 1.36, 95% CI 1.04-1.80, *P*=.03) and plus group (48.4%, 222/459; OR 1.58, 95% CI 1.20-2.07, *P=*.001) than in the control group (36.6%, 159/434). 

## Assessment of Moderation by Educational Level No significant interaction effects with educational level were found in the total sample and risk groups for fruit, vegetable, and saturated fat intake. Therefore, stratified analyses by educational level were not indicated for these behaviors. For high-energy snack intake, the interaction with education was borderline significant in both the total sample (*F*~4,932.32~=2.34, *P*=.053) and risk group (*F*~4,533.59~=2.37, *P*=.051). Therefore, stratified analyses by educational level were performed as additional analyses for high-energy snack intake. 

## Intervention Effects 

### Fruit Intake Even though fruit intake increased over time (*F*~2,953.39~=38.44, *P*\<.001), there was no difference in change over time between the 3 groups (*F*~4,1151.24~=1.09, *P*=.36) in the total sample ([Tables 2](#) and [3](#)). Among participants who consumed less than 2 pieces of fruit at baseline (n=803), a significant difference in change over time was found between the groups (*F*~4.523.71~=3.61, *P*=.007). The plus group had a significantly larger increase in fruit intake than the control group, between baseline and both T1 (plus vs control: ES =0.25, *P*=.01) and T2 (plus vs control: ES =0.37, *P*=.001). At medium term, the plus version also resulted in a larger increase in fruit intake than the basic version (plus vs basic: ES =0.22, *P*=.04) ([Tables 4](#) and [5](#)). ::::table-wrap
::: caption
Estimated marginal means at baseline and 1- and 4-month follow-ups and
changes over time for the total sample (N=1349).^a^
:::

______________________________________________________________________

Time point Fruit (pieces) Vegetables (grams) High-energy snacks (pieces) Saturated fat (fat points)

______________________________________________________________________

Mean (SE) Mean change Mean (SE) Mean change Mean (SE) Mean change Mean (SE) Mean change\
(95% CI)^b^ (95% CI)^b^ (95% CI)^b,c^ (95% CI)^b^

**Baseline**

```
                     Control          1.81 (0.06)          NA                            158.93 (3.31)                NA                3.21 (0.14)   NA                 17.96 0.29)    NA

                     Basic            1.94 (0.06)          NA                            163.24 (3.22)                NA                3.29 (0.14)   NA                 17.60 (0.29)   NA

                     Plus             1.83 (0.06)          NA                            158.96 (3.23)                NA                3.50 (0.14)   NA                 18.09 (0.29)   NA
```

**1-month follow-up**

```
                     Control          2.05 (0.07)          0.24                         164.30 (3.71)                5.37             3.06 (0.13)   --0.15            17.62 (0.31)   --0.33
                                                            (0.12, 0.36)                                               (--1.12, 11.86)                 (--0.39, 0.09)                    (--0.80, 0.14)

                     Basic            2.25 (0.07)          0.32                         180.34 (3.76)                17.10            2.42 (0.13)   --0.86            16.17 (0.31)   --1.43
                                                            (0.19, 0.44)                                               (10.44, 23.67)                  (--1.11, --0.62)                  (--1.91, --0.95)

                     Plus             2.22 (0.07)          0.39                         170.63 (3.81)                11.66            2.66 (0.13)   --0.84            17.36 (0.31)   --0.73
                                                            (0.27, 0.52)                                               (4.92, 18.43)                   (--1.08, --0.59)                  (--1.21, --0.25)
```

**4-month follow-up**

```
                     Control          2.00 (0.08)          0.19                         158.67 (3.76)                --0.27           2.84 (0.13)   --0.37            17.13 (0.30)   --0.83
                                                            (0.04, 0.33)                                               (--6.94, 6.41)                  (--0.62, --0.12)                  (--1.33, --0.33)

                     Basic            2.14 (0.08)          0.20                         173.28 (3.81)                10.03            2.50 (0.13)   --0.79            15.84 (0.31)   --1.77
                                                            (0.05, 0.34)                                               (3.18, 16.89)                   (--1.04, --0.53)                  (--2.82, --1.25)
```



## Plus 2.17 (0.08) 0.35 167.61 (3.92) 8.66 2.50 (0.13) --1.00 16.67 (0.31) --1.42 (0.20, 0.50) (1.60, 15.72) (--1.26, --0.74) (--1.95, --0.89)

^a^ Based on linear mixed model including place of residence, age,
education, study group, time, and group×time.

^b^ As compared to T0.

^c^ Significance tests based on natural logarithm of high-energy snacks.:::: ::::table-wrap
::: caption
Results of linear mixed model analyses for the total sample (N=1349).
:::

______________________________________________________________________

Outcome measure *F* (*df*) B^a^ (95% CI) *P* ES

______________________________________________________________________

**Fruit intake**

```
                               Group×time×education^b^                                   0.49 (4, 1015.26)     ---   .74                       ---      

                               Group×time^c^                                             1.09 (4, 1151.24)     ---   .36                       ---      

                               Time^d^                                                   38.44 (2, 953.39)     ---   <.001                    ---      

                               **Differences in change over time after 1 month (T1)**                                                               

                                                                                        Basic vs control^c^   ---   NA                        NA       NA

                                                                                        Plus vs control^c^    ---   NA                        NA       NA

                                                                                        Plus vs basic^c^      ---   NA                        NA       NA

                               **Differences in change over time after 4 months (T2)**                                                              

                                                                                        Basic vs control^c^   ---   NA                        NA       NA

                                                                                        Plus vs control^c^    ---   NA                        NA       NA

                                                                                        Plus vs basic^c^      ---   NA                        NA       NA
```

**Vegetable intake**

```
                               Group×time×education^b^                                   1.40 (4, 904.08)      ---   .23                       ---      

                               Group×time^c^                                             1.97 (4, 905.49)      ---   .10                       ---      

                               Time^d^                                                   16.69 (2, 906.08)     ---   <.001                    ---      

                               **Differences in change over time after 1 month (T1)**                                                               

                                                                                        Basic vs control^c^   ---   NA                        NA       NA

                                                                                        Plus vs control^c^    ---   NA                        NA       NA

                                                                                        Plus vs basic^c^      ---   NA                        NA       NA

                               **Differences in change over time after 4 months (T2)**                                                              

                                                                                        Basic vs control^c^   ---   NA                        NA       NA

                                                                                        Plus vs control^c^    ---   NA                        NA       NA

                                                                                        Plus vs basic^c^      ---   NA                        NA       NA
```

**High-energy snack intake**^e^

```
                               Group×time×education^b^                                   2.34 (4, 932.32)      ---   .053                      ---      

                               Group×time^c^                                             5.77 (4, 933.35)      ---   <.001                    ---      

                               Time^d^                                                   54.81 (2, 1310.46)    ---   <.001                    ---      

                               **Differences in change over time after 1 month (T1)**                                                               

                                                                                        Basic vs control^c^   ---   --0.71 (--1.06, --0.37)   <.001   --0.30

                                                                                        Plus vs control^c^    ---   --0.69 (--1.04, --0.34)   .001     --0.29

                                                                                        Plus vs basic^c^      ---   0.03 (--0.32, 0.37)       .36      0.01

                               **Differences in change over time after 4 months (T2)**                                                              

                                                                                        Basic vs control^c^   ---   --0.42 (--0.77, --0.06)   .006     --0.18

                                                                                        Plus vs control^c^    ---   --0.63 (--0.99, --0.27)   .002     --0.27

                                                                                        Plus vs basic^c^      ---   --0.21 (--0.58, 0.15)     .75      --0.09
```

**Saturated fat intake**

```
                               Group×time×education^b^                                   1.64 (4, 919.05)      ---   .16                       ---      

                               Group×time^c^                                             3.02 (4, 919.65)      ---   .02                       ---      

                               Time^d^                                                   39.29 (2, 919.57)     ---   <.001                    ---      

                               **Differences in change over time after 1 month (T1)**                                                               

                                                                                        Basic vs control^c^   ---   --1.10 (--1.77, --0.42)   .001     --0.19

                                                                                        Plus vs control^c^    ---   --0.40 (--1.07, 0.28)     .25      0.07

                                                                                        Plus vs basic^c^      ---   0.70 (0.02, 1.38)         .045     0.12

                               **Differences in change over time after 4 months (T2)**                                                              

                                                                                        Basic vs control^c^   ---   --0.94 (--1.66, --0.22)   .01      --0.17

                                                                                        Plus vs control^c^    ---   --0.59 (--1.32, 0.14)     .11      --0.11

                                                                                        Plus vs basic^c^      ---   0.35 (--0.39, 1.09)       .36      0.06
```

______________________________________________________________________

^a^ B=unstandardized regression coefficient for difference in change
over time between groups.

^b^ Based on linear mixed model including place of residence, age,
education, study group, time, group×time, time×education,
group×education, and group×time×education.

^c^ Based on linear mixed model including place of residence, age,
education, study group, time, and group×time.

^d^ Based on linear mixed model including place of residence, age,
education, study group, and time.

^e^ Repeated measures analyses on natural logarithm of high-energy
snacks; estimates based on original variable.:::: ::::table-wrap
::: caption
Estimated marginal means at baseline and at 1- and 4-month follow-ups
and changes over time for the risk groups.^a^
:::

______________________________________________________________________

Time point Fruit (pieces) Vegetables (grams) High-energy snacks (pieces) Saturated fat (fat points)\
(n=803) (n=1014) (n=808) (n=627)

______________________________________________________________________

```
                     Mean (SE)         Mean change          Mean (SE)                      Mean change                  Mean (SE)        Mean change    Mean (SE)          Mean change   
                                        (95% CI)^b^                                          (95% CI)^b^                                    (95% CI)^b,c^                      (95% CI)^b^    
```

**Baseline**

```
                     Control           1.04 (0.03)           NA                             130.53 (2.21)                 NA               4.75 (0.19)     NA                 22.98 (0.30)   NA

                     Basic             1.04 (0.03)           NA                             128.99 (2.18)                 NA               4.77 (0.18)     NA                 22.65 (0.30)   NA

                     Plus              1.03 (0.03)           NA                             127.27 (2.16)                 NA               5.03 (0.18)     NA                 22.82 (0.28)   NA
```

**1-month follow-up**

```
                     Control           1.56 (0.07)           0.52                          146.11 (3.66)                 16.08           4.10 (0.18)     --0.65            21.13 (0.42)   --1.85
                                                              (0.38, 0.66)                                                 (9.34, 22.82)                    (--1.01, --0.28)                  (--2.57, --1.13)

                     Basic             1.67 (0.08)           0.64                          157.78 (3.84)                 28.79           3.26 (0.18)     --1.51            19.35 (0.42)   --3.30
                                                              (0.49, 0.78)                                                 (21.65, 35.94)                   (--1.87, --1.15)                  (--4.03, --2.56)

                     Plus              1.80 (0.08)           0.78                          152.72 (3.82)                 25.45           3.41 (0.18)     --1.62            20.78 (0.41)   --2.04
                                                              (0.63, 0.92)                                                 (18.35, 32.56)                   (--1.98, --1.25)                  (--2.75, --1.33)
```

**4-month follow-up**

```
                     Control           1.41 (0.08)           0.37                          143.25 (3.61)                 12.72           3.80 (0.18)     --0.94            20.55 (0.41)   --2.43
                                                              (0.22, 0.52)                                                 (6.01, 19.43)                    (--1.32, --0.57)                  (--3.17, --1.69)

                     Basic             1.56 (0.09)           0.53                          153.20 (3.79)                 24.21           3.32 (0.18)     --1.46            18.83 (0.42)   --3.82
                                                              (0.36, 0.69)                                                 (17.11, 31.32)                   (--1.83, --1.08)                  (--4.57, --3.60)
```



## Plus 1.80 (0.09) 0.77 148.03 (3.86) 20.76 3.28 (0.19) --1.75 19.58 (0.43) --3.24 (0.60, 0.94) (13.53, 28.00) (--2.14, --1.37) (--4.03, --2.46)

^a^ Based on linear mixed model including place of residence, age,
education, study group, time, and group×time.

^b^ As compared to T0.

^c^ Significance tests based on natural logarithm of high-energy snacks.:::: ::::table-wrap
::: caption
Results of linear mixed model analyses for the risk groups.
:::

______________________________________________________________________

Outcome measure *F* (*df*) B^a^ (95% CI) *P* ES

______________________________________________________________________

**Fruit intake (n=803)**

```
                                          Group×time×education^b^                                   0.64 (4, 522.34)      ---   .64                       ---      

                                          Group×time^c^                                             3.61 (4, 523.71)      ---   .007                      ---      

                                          Time^d^                                                   136.31 (2, 523.62)    ---   <.001                    ---      

                                          **Differences in change over time after 1 month (T1)**                                                               

                                                                                                   Basic vs control^c^   ---   0.12 (--0.08, 0.32)       .25      0.11

                                                                                                   Plus vs control^c^    ---   0.26 (0.06, 0.46)         .01      0.25

                                                                                                   Plus vs basic^c^      ---   0.14 (--0.06, 0.35)       .18      0.12

                                          **Differences in change over time after 4 months (T2)**                                                              

                                                                                                   Basic vs control^c^   ---   0.16 (--0.07, 0.38)       .16      0.14

                                                                                                   Plus vs control^c^    ---   0.40 (0.18, 0.63)         .001     0.37

                                                                                                   Plus vs basic^c^      ---   0.25 (0.01, 0.48)         .04      0.22
```

**Vegetable intake (n=1014)**

```
                                          Group×time×education^b^                                   1.21 (4, 679.32)      ---   .31                       ---      

                                          Group×time^c^                                             2.15 (4, 671.86)      ---   .07                       ---      

                                          Time^d^                                                   72.11 (2, 654.00)     ---   <.001                    ---      

                                          **Differences in change over time after 1 month (T1)**                                                               

                                                                                                   Basic vs control^c^   ---   NA                        NA       NA

                                                                                                   Plus vs control^c^    ---   NA                        NA       NA

                                                                                                   Plus vs basic^c^      ---   NA                        NA       NA

                                          **Differences in change over time after 4 months (T2)**                                                              

                                                                                                   Basic vs control^c^   ---   NA                        NA       NA

                                                                                                   Plus vs control^c^    ---   NA                        NA       NA

                                                                                                   Plus vs basic^c^      ---   NA                        NA       NA
```

**High-energy snack intake**^e^**(n=808)**

```
                                          Group x time x education^b^                               2.37 (4, 533.59)      ---   .051                      ---      

                                          Group x time^c^                                           4.30 (4, 534.96)      ---   .002                      ---      

                                          Time^d^                                                   144.93 (2, 535.40)    ---   <.001                    ---      

                                          **Differences in change over time after 1 month (T1)**                                                               

                                                                                                   Basic vs control^c^   ---   --0.86 (--1.38, --0.35)   <.001   -0.34

                                                                                                   Plus vs control^c^    ---   --0.97 (--1.49, --0.45)   .001     -0.38

                                                                                                   Plus vs basic^c^      ---   --0.11 (--0.62, 0.41)     .90      -0.04

                                          **Differences in change over time after 4 months (T2)**                                                              

                                                                                                   Basic vs control^c^   ---   --0.51 (--1.04, 0.02)     .02      --0.20

                                                                                                   Plus vs control^c^    ---   --0.81 (--1.34, --0.28)   .008     --0.32

                                                                                                   Plus vs basic^c^      ---   --0.30 (--0.83, 0.24)     .74      --0.12
```

**Saturated fat intake (n=627)**

```
                                          Group×time×education^b^                                   0.90 (4, 425.13)      ---   .46                       ---      

                                          Group×time^c^                                             2.99 (4, 441.26)      ---   .02                       ---      

                                          Time^d^                                                   112.02 (2, 419.08)    ---   <.001                    ---      

                                          **Differences in change over time after 1 month (T1)**                                                               

                                                                                                   Basic vs control^c^   --    --1.45 (--2.48, --0.42)   .006     --0.28

                                                                                                   Plus vs control^c^    --    --0.19 (--1.20, 0.83)     .72      --0.04

                                                                                                   Plus vs basic^c^      --    1.26 (0.24, 2.28)         .02      0.24

                                          **Differences in change over time after 4 months (T2)**                                                              

                                                                                                   Basic vs control^c^   ---   --1.38 (--2.44, --0.33)   .01      --0.28

                                                                                                   Plus vs control^c^    ---   --0.81 (--1.89, 0.27)     .14      --0.16

                                                                                                   Plus vs basic^c^      ---   0.58 (--0.51, 1.66)       .30      0.12
```

______________________________________________________________________

^a^ B=unstandardized regression coefficient for difference in change
over time between groups.

^b^ Based on linear mixed model including place of residence, age,
education, study group, time, group×time, time×education,
group×education, and group×time×education.

^c^ Based on linear mixed model including place of residence, age,
education, study group, time, and group×time.

^d^ Based on linear mixed model including place of residence, age,
education, study group, and time.

^e^ Repeated measures analyses on natural logarithm of high-energy
snacks; estimates based on original variable.:::: 

### Vegetable Intake Vegetable intake increased over time in the total sample (*F*~2,906.08~=16.69, *P*\<.001), but there was no difference in change over time between the 3 groups (*F*~4,905.49~=1.97, *P*=.10) ([Tables 2](#) and [3](#)). The same results were found in the risk group: vegetable intake increased over time (*F*~2,654.00~=72.11, *P*\<.001), but no difference between the 3 groups was found (*F*~4,671.86~=2.15, *P*=.07)([Tables 4](#) and [5](#)). 

### High-Energy Snack Intake High-energy snack intake had a very skewed distribution and, therefore, was log-transformed. The significance tests were based on the log-transformed variable, but the unstandardized regression coefficients and ES were based on the original variable. In the total sample, there was a significant difference in decrease of high-energy snacks between the groups (*F*~4,933.35~=5.77, *P*\<.001). Both intervention groups had a significantly larger decrease in high-energy snack intake than the control group between baseline and both T1 (basic vs control: ES =--0.30, *P*\<.001; plus vs control: ES =--0.29, *P*=.001) and T2 (basic vs control: ES =--0.18, *P*=.006; plus vs control: ES =--0.27, *P*=.002) ([Tables 2](#) and [3](#)). Stratified analyses showed that for lower-educated participants both the basic and plus version resulted in a larger decrease than the control intervention between baseline and T1 (basic vs control: ES =--0.33, *P*\<.001; plus vs control: ES =--0.23, *P*=.02). Between baseline and T2, only the basic version resulted in a larger decrease than the control intervention (basic vs control: ES =--0.23, *P*=.009). For high-educated participants, both intervention groups had a larger decrease than the control group between baseline and T1 (basic vs control: ES =--0.31, *P*=.006; plus vs control: ES =--0.38, *P*=.01\*).\* Between baseline and T2, the plus version resulted in a larger decrease than the control intervention (plus vs control: ES =--0.53, *P*\<.001) and basic version (plus vs basic: ES =--0.32, *P*=.04). Also in the risk group (n=808), significant differences in change over time were found (*F*~4,534.96~=4.30, *P*=.002). Both intervention groups had a significant larger decrease than the control group between baseline and T1 (basic vs control: ES =--0.34, *P*\<.001; plus vs control: ES =--0.38, *P*=.001) and T2 (basic vs control: ES =--0.20, *P*=.02; plus vs control: ES =--0.32, *P*=.008) ([Tables 4](#) and [5](#)). Stratified analyses showed that among lower-educated participants only the basic version resulted in a larger decrease in high-energy snack intake than the control intervention between baseline and both T1 (basic vs control: ES =--0.40, *P*=.002) and T2 (basic vs control: ES =--0.26, *P*=.03). For higher-educated participants, both intervention groups had a larger decrease than the control group between baseline and T1 (basic vs control: ES =--0.34, *P*=.02; plus vs control: ES=--0.50, *P*=.001). Between baseline and T2, the plus version resulted in a larger decrease than the control intervention (plus vs control: ES =--0.64, *P*\<.001) and basic version (plus vs basic: ES =--0.38, *P*=.03). 

### Fat Intake Differences in change over time between the groups were found (*F*~4,919.65~=3.02, *P*=.02) in the total sample. The basic group had a larger decrease in saturated fat intake than the control group between baseline and both T1 (basic vs control: ES =--0.19, *P*=.001) and T2 (basic vs control: ES =--0.17, *P*=.01). In addition, the decrease between baseline and T1 was significantly smaller for the plus group compared to the basic group (plus vs basic: ES =0.12, *P*=.045) ([Tables 2](#) and [3](#)). Also in the risk group (n=627), differences in change over time between the groups were found (*F*~4,441.26~=2.99, *P*=.02). The basic group had a significantly larger decrease in saturated fat intake than the control group between baseline and both T1 (basic vs control: ES=--0.28, *P*=.006) and T2 (basic vs control: ES=--0.28, *P*=.01). Between baseline and T1, the decrease was lower for the plus group than for the basic group (plus vs basic: ES =0.24, *P*=.02) ([Tables 4](#) and [5](#)).


Extracted trial result:
Outcome: High-energy snack intake (continuous)
Intervention: Individual cognition and self-regulation processes intervention
Comparator: Control
Intervention group size: 459
Intervention mean: 2.5
Intervention standard deviation: 2.79
Comparator group size: 434
Comparator mean: 2.84
Comparator standard deviation: 2.71
Notes: Values are from 4-month follow up (final timepoint). Back calculated the SD values from SE.