A Health Game Targeting Children's Implicit Attitudes and Snack Choices

Objective: The present study investigated whether a health game can be used to affect children's implicit attitudes toward food (IAsTF) and subsequent snack choices. Materials and Methods: The health game used was based on an evaluative conditioning paradigm. The experiment followed a between-subjects design with two conditions (health game vs. control), N = 79 (12.42 years ±1.64, body mass index: 25.06 ± 7.40). IAsTF were assessed at baseline and postintervention using an implicit association test (IAT). Baseline IAT scores were used to categorize IAsTF as healthy (favoring fruits) versus unhealthy IAsTF (favoring chocolates). In addition, three digital snack choices were recorded. Results: No main effect of condition on posttest IAsTF was found. However, baseline IAsTF moderated the effect of condition on posttest IAsTF; participants with less healthy baseline IAsTF playing the health game had healthier posttest IAsTF compared to those playing the control game. Regarding the snack choices, participants playing the health game favored fruit over chocolate in one of the snack choices. Baseline IAsTF did not moderate the effect of condition on snack choices. Conclusion: Tentative support was found that health games can be used to improve IAsTF, in particular among participants with less healthy ones at baseline.

Investigating the impact of a health game on implicit attitudes towards food and food choice behaviour of young adults

Improving diets by stimulating fruit and vegetable consumption might be beneficial, in particular when they substitute energy-dense products. The aim of present study was to investigate whether a health game can be used to positively affect healthy implicit attitudes (IAs) towards food and subsequent food choice behaviour of young adults. A 2 (Time: baseline vs. post-test) x 2 (Condition: health game vs. control game) x 2 (Baseline IAs: healthy IAs vs. less healthy IAs) mixed-subjects design was used with 125 participants (age: M = 20.17, SD = 1.88). IAs towards food were assessed at baseline and post-test using an Implicit Association Test (IAT). Additionally, food choice behaviour was assessed after game play. At baseline, the majority of participants had healthy IAs (i.e., favouring fruit over chocolate snacks). At post-test, significantly less healthy IAs were observed in the control condition, while this reduction was not significant in the health game condition. Regarding food choice behaviour, participants with healthy baseline IAs were more likely to select fruit in the health game condition than participants with healthy baseline IAs in the control game condition. However, participants with less healthy baseline IAs were less likely to select fruit in the health game condition than in the control condition. We found tentative support that health games can be used to influence IAs towards food and positively affect food choice behaviour. However, this influence was only observed for those with healthy baseline IAs. The current version of the health game would primarily benefit those already healthy and could negatively affect those that need the intervention most, so modifications are recommendable.

Formation of Polyesters by Pseudomonas oleovorans : Effect of Substrates on Formation and Composition of Poly-( R )-3-Hydroxyalkanoates and Poly-( R )-3-Hydroxyalkenoates

Pseudomonas oleovorans grows on C 6 to C 12 n -alkanes and 1-alkenes. These substrates are oxidized to the corresponding fatty acids, which are oxidized further via the β-oxidation pathway, yielding shorter fatty acids which have lost one or more C 2 units. P. oleovorans normally utilizes β-oxidation pathway intermediates for growth, but in this paper we show that the intermediate 3-hydroxy fatty acids can also be polymerized to intracellular poly-( R )-3-hydroxyalkanoates (PHAs) when the medium contains limiting amounts of essential elements, such as nitrogen. The monomer composition of these polyesters is a reflection of the substrates used for growth of P. oleovorans . The largest monomer found in PHAs always contained as many C atoms as did the n -alkane used as a substrate. Monomers which were shorter by one or more C 2 units were also observed. Thus, for C-even substrates, only C-even monomers were found, the smallest being ( R )-3-hydroxyhexanoate. For C-odd substrates, only C-odd monomers were found, with ( R )-3-hydroxyheptanoate as the smallest monomer. 1-Alkenes were also incorporated into PHAs, albeit less efficiently and with lower yields than n -alkanes. These PHAs contained both saturated and unsaturated monomers, apparently because the 1-alkene substrates could be oxidized to carboxylic acids at either the saturated or the unsaturated ends. Up to 55% of the PHA monomers contained terminal double bonds when P. oleovorans was grown on 1-alkenes. The degree of unsaturation of PHAs could be modulated by varying the ratio of alkenes to alkanes in the growth medium. Since 1-alkenes were also shortened before being polymerized, as was the case for n -alkanes, copolymers which varied with respect to both monomer chain length and the percentage of terminal double bonds were formed during nitrogen-limited growth of P. oleovorans on 1-alkenes. Such polymers are expected to be useful for future chemical modifications.