Does misperception of fruit and vegetable intake adequacy affect progression through the stages of behavior change after nutritional intervention?

Pseudomaintenance (PM) is a Transtheoretical Model (TTM) stage of change that refers to individuals who believe they eat enough fruit and vegetables (FV) despite their low FV intake. It is not known how they change behavior after usual TTM-based interventions. Thus, this randomized controlled community trial describes the effect of PM on progression through the stages of change for FV intake among adult and elderly health promotion service users after TTM-based intervention. The stage of change for FV intake was assessed; FV intake was estimated from brief validated questions at baseline (n = 3414) and follow-up (n = 1782). Individuals whose perception of adequacy matched the estimated intake were labeled as concordant perception, while those with low intake who believed that their intake was adequate were classified as being in PM. The intervention group received the intervention while the control group received usual care. The prevalence of no stage progression at follow-up was close to 50% for those in PM at baseline. After adjustment for demographics, randomization, self-efficacy, decisional balance, and baseline intake, users in PM at baseline had higher odds [OR = 1.53 (1.21-1.94)] of progressing to higher stages for fruit and no difference in progression for vegetables. We propose strategies to approach FV intake in future studies and reinforce the need for additional trials aimed at describing changes in FV intake among individuals in PM, in order to continue answering the scientific questions that we began to investigate.