Measuring satiety with pictures compared to visual analogue scales. An exploratory study

Visual analogue scales (VAS) are a standard tool used to measure subjective appetite. To explore a potentially more intuitive and precise alternative, we developed a method based on pictures and assessed its performance characteristics vs. VAS. The objective was to compare the capacity of the two methods to discriminate appetite ratings between interventions. Both methods were applied within a previously published trial in which 16 healthy adults received standardised meals followed by three different ileal infusions in a balanced crossover design. At regular intervals volunteers indicated how many units of individually pictured food portions (for 10 different items) they would like to eat, and also scored six VAS. Methods were compared over different timeframes and assessed for their sensitivity to intervention effects. Pictures were more sensitive than VAS in differentiating intervention effects; however, further refinement and validation would be needed for pictures to become a standardised and accepted alternative to VAS for this type of research.