Financial incentive policies at workplace cafeterias for preventing obesity–a systematic review and meta-analysis.

BACKGROUND
Various studies are currently investigating ways to prevent lifestyle-related diseases and obesity among workers through interventions using incentive strategies, including price discounts for low-fat snacks and sugar-free beverages at workplace cafeterias or vending machines, and the provision of a free salad bar in cafeterias. Rather than assessing individual or group interventions, we will focus on the effectiveness of nutrition education programs at the population level, which primarily incorporate financial incentive strategies to prevent obesity. This paper describes the protocol of a systematic review that will examine the effectiveness of financial incentive programs at company cafeterias in improving dietary habits, nutrient intake and obesity prevention.

METHODS
We will conduct searches in CENTRAL, MEDLINE, EMBASE, and Psych INFO.Interventions will be assessed using data from randomized control trials (RCT) and cluster RCTs. However, if few such trials exist, we will include quasi-RCTs. We will exclude controlled before-and-after studies and cross-over RCTs. We will assess food-based interventions that include financial incentive strategies (discount strategies or social marketing) for workplace cafeterias, vending machines, and kiosks. Two authors will independently review studies for inclusion and will resolve differences by discussion and, if required, through consultation with a third author. We will assess the risk of bias of included studies according to the Cochrane Collaboration's 'risk of bias' tool.

DISCUSSION
The purpose of this paper is to outline the study protocol for a systematic review and meta-analysis that will investigate the effectiveness of population-level, incentive-focused interventions at the workplace cafeteria that aim to promote and prevent obesity. This review will give an important overview of the available evidence about the effectiveness of incentive-based environmental interventions to improve obesity prevention in the workplace, and will guide future research in nutrition education and health promotion globally.