The Impact of Optical Impressions on Dog Feeding Practice

According to the literature, as many as 60% of domestic dogs are overweight, whereby obesity is implicated in many serious diseases and hence a reduction of body weight results in a reduced risk of disease. Approximately 32% of reduction diets are unsuccessful in helping dogs to reach their ideal body weight. The likely reasons for this high drop-out rate include, among others, the fear of increased hunger-induced distress or a loss of affection on the part of the pet towards the owner. To alleviate these apprehensions, the use of optical effects that increase the perceived food intake could be useful. To investigate this, a mixed-methods study design was applied and 100 test persons-including dog owners and non-owners-were instructed to fill up 11 separate dog bowls with the same amount of dogfood. The bowls varied in 5 different variables (total height, upper diameter, angulation of sidewall, volume, and color). The influence of the shape and color of the dog bowls in relation to the filling quantity was evaluated. Overall, the body of the inner food bowl-especially its diameter and shape-showed a significant impact on the feeder as the wider the diameter, the more the dog bowl was filled. Moreover, the flatter the sidewall was angulated, the larger the fill-up quantity. Significantly, the volume on its own did not have a significant impact on the feeder. A difference of up to 37.6% in fill quantity resulted depending on the type of dog bowl used. Furthermore, the use of inner cones confused the test persons whereas different colors and the total height of the bowl showed no impact. Dog bowls with a small upper diameter and a steep sidewall-regardless of volume and color-were filled less by the test persons. This tendency could be useful for adapting the feeding of overweight dogs or those with an increased risk of obesity.