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Millions of people now access personal genetic risk estimates for diseases such as Alzheimer’s, cancer, and obesity1. While this information can be informative2–4, research on placebo and nocebo effects5–8 suggests that learning one’s genetic risk may evoke physiological changes consistent with the expected risk profile. Here we tested whether merely learning one’s genetic risk for disease alters one’s actual risk by making people more likely to exhibit the expected changes in gene-related physiology, behaviour, and subjective experience. Individuals were genotyped for actual genetic risk and then randomly assigned to receive either a “high-risk” or “protected” genetic test result for obesity via cardiorespiratory exercise capacity (Experiment 1, N = 116) or physiological satiety (Experiment 2, N = 107) before engaging in a task in which genetic risk was salient. Merely receiving genetic risk information changed individuals’ cardiorespiratory physiology, perceived exertion, and running endurance during exercise, and changed satiety physiology and perceived fullness after food consumption in a self-fulfilling manner. Effects of perceived genetic risk on outcomes were sometimes greater than effects associated with actual genetic risk. If simply conveying genetic risk information can alter actual risk, clinicians and ethicists should wrestle with appropriate thresholds for when revealing genetic risk is warranted.

Describing the most nutritious menu options in less appealing terms may perpetuate beliefs that healthy foods are not flavorful or indulgent, and may undermine customers' choice of healthier dining options. From a public health perspective, incorporating more appealing descriptive language to boost the appeal of nutritious foods may be one avenue to improve dietary health. (PsycINFO Database Record

Healthy food labels tout health benefits, yet most people prioritize tastiness in the moment of food choice. In a preregistered intervention, we tested whether taste-focused labels compared with health-focused labels increased vegetable intake at five university dining halls throughout the United States. Across 137,842 diner decisions, 185 days, and 24 vegetable types, taste-focused labels increased vegetable selection by 29% compared with health-focused labels and by 14% compared with basic labels. Vegetable consumption also increased. Supplementary studies further probed the mediators, moderators, and boundaries of these effects. Increased expectations of a positive taste experience mediated the effect of taste-focused labels on vegetable selection. Moderation tests revealed greater effects in settings that served tastier vegetable recipes. Taste-focused labels outperformed labels that merely contained positive words, fancy words, or lists of ingredients. Together, these studies show that emphasizing tasty and enjoyable attributes increases vegetable intake in real-world settings in which vegetables compete with less healthy options.

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