The development and evaluation of a novel online tool for assessing dietary intake and physical activity levels for use in adult populations

The Synchronised Nutrition and Activity Program for Adults (SNAPA™) was developed to address the need for accurate, reliable, feasible, inexpensive and low burden methods for measuring diet and physical activity behaviours in free-living adult populations. Usability testing (n=5) identified a number of usability issues and the program was revised accordingly. Test-retest reliability (n=44) revealed no substantial systematic shifts in mean values. Outcome variables were percentage food energy from fat (%fat), number of fruit and vegetable portions (FV), and minutes of moderate to vigorous activity (MVPA). Single measure intra-class correlations (ICC) ranged from 0.62 to 0.72 and average measure ICC range from 0.76 to 0.84. The preliminary method comparison study (n=71) revealed correlations between SNAPA™ and multiple pass recall dietary interview-derived %fat and FV portions of 0.48 (bootstrapped 90% CI 0.31, 0.64) and 0.42 (bootstrapped 90% CI 0.22, 0.60) respectively. The correlation between SNAPA™ and accelerometry-derived MVPA was 0.39 (bootstrapped 90% CI 0.08, 0.64). The in-depth primary method comparison study (n=77) investigated the agreement between SNAPA™ and dietary observation and combined heart rate and accelerometry. The mean match and phantom rates between SNAPA™ and lunchtime dietary observation was 81.7% and 5.6%, respectively. Correlations between SNAPA™ and the reference method outcomes ranged between 0.39 and 0.56. Passing-Bablok (type II) regression analysis revealed both fixed and proportional bias for the estimation of energy intake; proportional bias for fat intake (g); a fixed bias for MVPA, and no substantial biases for %fat or FV portions. SNAPA™ was used to collect diet and physical activity data in a health promotion campaign, ‘Get a Better Life’ (n=1201), providing useful information on the feasibility of using the program in a real-world initiative. SNAPA™ is a promising tool for the surveillance of diet and physical behaviours at a group level in adult populations.