The researchers examined how non-pathological levels of depression, anxiety and experimentally manipulated moods could affect participants' oral perceptions of fat and other taste stimuli like sweet, sour, bitter and umami flavors. Participants in the study were scored for symptoms of depression and anxiety, and shown video clips of happy, sad and neutral scenes from movies to put them in a positive, negative or neutral mood. Before and after watching the clips, they were asked to rate a series of liquids based on the intensity of flavor they experienced. They were also asked to gauge the fat content in milk samples by mouth-feel.
After watching a happy or sad movie clip, participants with mild, subclinical signs of depression were unable to tell the difference between a high-fat and low-fat sample, whereas they could distinguish between the two after watching a clip from a neutral film, as well as before they watched the movies. These participants with higher depression scores also rated bitter and sweet tastes as being more intense after they watched the movie clips than they did before this mood-inducing exercise. The authors conclude that their results may have potential implications for unhealthy eating patterns, as this inability to distinguish tastes may cause mildly depressed individuals to unconsciously eat more fatty foods.