Daily fat intake is associated with basolateral amygdala response to high-calorie food cues and appetite for high-calorie food.

Objectives: Animal studies have indicated that fat intake mediates amygdala activation, which in turn promotes fat intake, while amygdala activation increases the preference for fat and leads to increased fat intake. However, the association among fat intake, amygdala activation, and appetite for high-calorie foods in humans remains unclear. Thus, to examine this association, we conducted a functional magnetic resonance imaging (fMRI) experiment.

Methods: Fifty healthy-weight adults (18 females; mean age: 22.9 ± 3.02 years) were included. Participants were shown images of high-calorie and low-calorie foods and were instructed to rate their desire to eat the food items during fMRI. All participants provided information on their daily fat intake using a self-reported questionnaire. Associations among fat intake, the desire to eat high-calorie or low-calorie food items, and amygdala responses to food items were examined.

Results: The basolateral amygdala (BLA) response was positively associated with fat intake ([x, y, z] = [24, -6, -16], z = 3.91, p_{FWE-corrected} = 0.007) and the desire to eat high-calorie food items ([26, -4, -16], z = 3.75, p_{FWE-corrected} = 0.010). Structural equation modeling showed that the desire for high-calorie food items was predicted by BLA response to high-calorie food items (p = 0.013, β = 3.176), and BLA response was predicted by fat intake (p < 0.001, β = 0.026).

Discussion: Fat intake influences BLA response to high-fat food, which in turn increases the desire to eat palatable high-fat food. This may lead to additional fat intake and increase the risk of weight gain.