What this Trial Is About

This study experimentally investigates whether a reduction in ultra-processed (UP) food intake (1) causes aversive withdrawal symptoms in humans, (2) increases the motivational salience of UP food cues and, if so, (3) whether these factors undermine the ability to adhere to a low-UP diet. The following aims and hypotheses are tested: Aim 1: To investigate whether aversive physical, cognitive, and affective withdrawal symptoms emerge in response to reduced UP food intake compared to a high-UP diet, and whether this predicts failure to adhere to a low-UP diet. H1a: Reducing UP food intake will result in aversive physical, cognitive, and affective withdrawal symptoms, as indicated by 1) ecological momentary assessment (EMA) reports of aversive withdrawal symptoms, and 2) heart rate reactivity and subjective distress to an in-lab stressor. H1b: Aversive symptoms of UP food withdrawal will predict greater UP food intake and higher blood glucose levels when trying to adhere to a low UP diet. Aim 2: To investigate whether increased motivational salience of UP food cues emerges in response to reduced UP food intake, and whether this predicts failure to maintain a low-UP diet. H2a: Reducing UP food intake will result in increased motivational salience of UP food cues, as indicated by 1) EMA reports of UP food craving, 2) heart rate reactivity and subjective craving in a simulated fast-food restaurant, 3) heightened reinforcement value for UP food relative to other reinforcers, and 4) greater reward-related neural response to UP food cues. H2b: Increased motivational salience of UP food cues will predict greater UP food intake and higher blood glucose levels when trying to adhere to a low UP diet.

Ultra Crave: An Investigation of Ultra-Processed Food