The human brain needs only milliseconds to assess the nutritional content of a food item, even if it's only an image.
Scientists from four institutions, including Lausanne University and the Nestlé Research Centre, found it takes about 200 milliseconds for the brain to discriminate between high- and low-fat foods.
According to a study to be published in the journal NeuroImage on February 1, scientists presented healthy adults with pictures of foods and non-foods. They used brain-imaging equipment to monitor how the adults reacted.
The food images were secretly divided up into high- and low-fat foods, and the brain reacted differently to each. Pictures of high-fat foods stimulated areas of the brain that handle decision-making and reward potential more strongly than low-fat foods did.
Micah Murray, a neuroscientist and leader of the study, said this suggests that the brain can rapidly assess the nutritional value of food items by using the same regions that handle categorization.