Emerging data suggest that weight gain is associated with changes in neural response to palatable food tastes and cues for palatable foods that may serve to maintain overeating. We investigated whether weight gain is associated with altered neural response to milkshakes varying in fat and sugar content.
We compared changes in neural activity between initially healthy weight adolescents who gained weight (n = 36) and those showing weight stability (n = 31) over 2-3 years.
Adolescents who gained weight versus weight stable adolescents showed decreases in activation in the postcentral gyrus, prefrontal cortex, insula, putamen, lingual gyrus, temporal gyrus, anterior cingulate cortex, and anterior cerebellum and increases in activation in the parietal lobe, posterior cingulate cortex, thalamus, and inferior frontal gyrus in response to a high-fat/low-sugar versus low-fat/low-sugar milkshake. They also showed greater decreases in activation in the anterior insula, orbitofrontal cortex, and medial prefrontal cortex in response to a high-fat/high-sugar versus low-fat/low-sugar milkshake compared to weight stable adolescents. The effects were partially driven by opposite changes in neural activation in adolescents who remained weight stable. No group differences emerged in response to a low-fat/high-sugar versus low-fat/low-sugar milkshake.
Data suggest that weight gain is associated with a decrease in hedonic value of palatable, high-fat- and high-fat/high-sugar foods and a reduction in sensitivity to the taste properties of these foods. The pattern of findings also implies that maintaining a healthy weight increases taste sensitivity, which may prevent future weight gain.