The role of distinct food reward processing stages in restrained eating subtypes: An ERP study.

Restrained eating refers to the intention to limit food intake for weight control, yet individuals differ in their ability to maintain this behavior, leading to their classification as either successful (SREs) or unsuccessful (UREs) restrained eaters. Although reward processing is known to influence eating behavior, how this processing at distinct stages relates to individual differences in restrained eating remains unclear. This study employed a food incentive delay task combined with event-related potentials (ERPs) to compare electrophysiological activity between SREs (n = 30) and UREs (n = 30) during both wanting and liking stages of reward processing. Specifically, we measured two anticipatory ERPs (i.e., "wanting"): the contingent negative variation (CNV) during target anticipation and the stimulus preceding negativity (SPN) during feedback anticipation; and one consummatory ERP (i.e., "liking"): the P300 component during feedback receipt. Results revealed no group differences in CNV amplitudes, suggesting similar motor preparation. In contrast, SPN amplitudes were larger for food reward compared to neutral trials. Crucially, UREs exhibited larger SPN amplitudes specifically in high-calorie food reward than SREs, indicating stronger wanting. During feedback receipt, although P300 amplitudes were larger in reward trials than neutral trials, no significant group differences were observed, suggesting similar levels of liking toward food rewards across groups. This is the first study to provide electrophysiological evidence that differences between SREs and UREs emerge primarily during food reward anticipation, rather than receipt, indicating that heightened wanting may contribute to dietary failures in UREs.