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Studies about effects of school lunch on children's cognition are rare; two previous studies (CogniDo, CogniDo PLUS) generally found no negative effects of lunch on children's cognitive performance at the end of lunch break (i.e. 45 min after finishing lunch), but suggested potential beneficial effects for single parameters. Therefore, the present study investigated the hypothesis of potential positive effects of school lunch on cognitive performance at early afternoon (90 min after finishing lunch). A randomised, cross-over intervention trial was conducted at a comprehensive school with fifth and sixth grade students. Participants were randomised into two groups: On day 1, group 1 did not eat lunch, whereas group 2 received lunch ad libitum. On day 2 (1 week later), group 2 did not eat lunch and group 1 received lunch ad libitum. The cognitive parameters task switching, working memory updating and alertness were tested using a computerised test battery 90 min after finishing the meal. Of the 204 recruited children, fifty were excluded because of deviations from the study protocol or absence on one of the 2 test days, which resulted in 154 participants. Data showed no significant effects of lunch on task switching, working memory updating and alertness (P values between 0·07 and 0·79). The present study suggests that school lunch does not seem to have beneficial effects on children's cognitive functions regarding the conducted tests at early afternoon. Together with our previous studies, we conclude that school lunch in general has no negative effects on cognitive performance in children. However, beneficial effects seem to be restricted to a relatively short time period after eating lunch. Considering the extension of all-day schools in Europe, knowledge about potential effects of school lunch on children's cognition is becoming increasingly important. Short-term lunch effects on cognition were primarily examined in adults with equivocal results, until now. Although sustained attention and the ability to discriminate have been shown to be worsened after lunch (1,2) , other cognitive aspects were improved (reading ability) (3) or did not change (selective attention) (4) . One explanation for negative lunch effects on cognitive performance is the post-lunch dip -a naturally occurring nadir in performance at midday. Studies in adults have shown that this dip is worsened by lunch (5,1) . Therefore, it could be hypothesised that skipping lunch could result in an alleviation or prevention of this post-lunch dip. However, these results were obtained in adults and are not necessarily transferable to children due to constitutional and metabolic differences between children and adults (e.g. still rapid brain growth, high metabolic rate in children). Until now, studies in children about the effects of meals on cognition have mainly concentrated on breakfast (6) . A body of research work has shown short-term benefits for cognitive performance when children eat breakfast instead of skipping it (6) . However, other s...

Summary The Community Readiness Model (CRM) provides an approach to determine community readiness (CR), which is the degree of a community’s preparedness to address a health issue. This scoping review aims to characterize internationally existing applications of the CRM for childhood obesity prevention. Therefore, a systematic literature research was conducted in PubMed, Cochrane Library, LIVIVO and Google Scholar. Of 285 identified records, 17 studies met the eligibility criteria and were included in the scoping review. The CRM has already been applied to childhood obesity prevention in the USA (n = 10), Australia (n = 4), UK (n = 1), Iran (n = 1) and South Africa (n = 1). Mainly geographically defined communities (n = 12) like counties and cities were analysed but also schools (n = 4) and churches (n = 1). The scoping review revealed various methodological changes to the standard protocol of which some are particularly relevant for the application to childhood obesity prevention. The identified studies reported readiness scores in the low to mid-range of the nine-point readiness scale. To increase CR, strategies were proposed that addressed raising awareness and knowledge of childhood obesity, but also supporting connectivity in and between settings. This scoping review provides researchers and health promoters with an overview of international CR measurements and setting-specific strategies to increase CR. It highlights the potential of targeted interventions to increase readiness and shows tentative support for the assumption of a possible link between CR level and changes in obesity prevalence.

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