To review research evidence on the effectiveness of
monetary incentives in modifying dietary behavior, we
conducted a systematic review of randomized, controlled
trials (RCTs) identified from electronic bibliographic
databases and reference lists of retrieved
relevant articles. Studies eligible for inclusion met the
following criteria: RCT comparing a form of monetary
incentive with a comparative intervention or
control; incentives were a central component of the
study intervention and their effect was able to be
disaggregated from other intervention components;
study participants were community-based; and outcome
variables included anthropometric or dietary
assessment measures. Data were extracted on study
populations, setting, interventions, outcome variables,
trial duration, and follow-up. Appraisal of trial methodological
quality was undertaken based on comparability
of baseline characteristics, randomization
method, allocation concealment, blinding, follow-up,
and use of intention-to-treat analysis. Four RCTs
were identified as meeting the inclusion criteria. All
four trials demonstrated a positive effect of monetary
incentives on food purchases, food consumption, or
weight loss. However, the trials had some methodological
limitations including small sample sizes and
short durations. In addition, no studies to date have
assessed effects according to socioeconomic or ethnic
group or measured the cost-effectiveness of such
schemes. Monetary incentives are a promising strategy
to modify dietary behavior, but more research is needed to address the gaps in evidence. In particular,
larger, long-term RCTs are needed with population
groups at high risk of nutrition-related diseases.