A systematic review of financial incentives for dietary behavior change.

In light of the obesity epidemic, there is growing interest in the use of financial incentives for dietary behavior change. Previous reviews of the literature have focused on randomized controlled trials and found mixed results. The purpose of this systematic review is to update and expand on previous reviews by considering a broader range of study designs, including randomized controlled trials, quasi-experimental, observational, and simulation studies testing the use of financial incentives to change dietary behavior and to inform both dietetic practice and research. The review was guided by theoretical consideration of the type of incentive used based on the principles of operant conditioning. There was further examination of whether studies were carried out with an institutional focus. Studies published between 2006 and 2012 were selected for review, and data were extracted regarding study population, intervention design, outcome measures, study duration and follow-up, and key findings. Twelve studies meeting selection criteria were reviewed, with 11 finding a positive association between incentives and dietary behavior change in the short term. All studies pointed to more specific information on the type, timing, and magnitude of incentives needed to motivate individuals to change behavior, the types of incentives and disincentives most likely to affect the behavior of various socioeconomic groups, and promising approaches for potential policy and practice innovations. Limitations of the studies are noted, including the lack of theoretical guidance in the selection of incentive structures and the absence of basic experimental data. Future research should consider these factors, even as policy makers and practitioners continue to experiment with this potentially useful approach to addressing obesity.

Change in food cravings, food preferences, and appetite during a low-carbohydrate and low-fat diet.

The study objective was to evaluate the effect of prescribing a low-carbohydrate diet (LCD) and a low-fat diet (LFD) on food cravings, food preferences, and appetite. Obese adults were randomly assigned to a LCD (n = 134) or a LFD (n = 136) for 2 years. Cravings for specific types of foods (sweets, high-fats, fast-food fats, and carbohydrates/starches); preferences for high-sugar, high-carbohydrate, and low-carbohydrate/high-protein foods; and appetite were measured during the trial and evaluated during this secondary analysis of trial data. Differences between the LCD and LFD on change in outcome variables were examined with mixed linear models. Compared to the LFD, the LCD had significantly larger decreases in cravings for carbohydrates/starches and preferences for high-carbohydrate and high-sugar foods. The LCD group reported being less bothered by hunger compared to the LFD group. Compared to the LCD group, the LFD group had significantly larger decreases in cravings for high-fat foods and preference for low-carbohydrate/high-protein foods. Men had larger decreases in appetite ratings compared to women. Prescription of diets that promoted restriction of specific types of foods resulted in decreased cravings and preferences for the foods that were targeted for restriction. The results also indicate that the LCD group was less bothered by hunger compared to the LFD group and that men had larger reductions in appetite compared to women.