Bet you can't eat just one: Testing the abuse liability of hyper-palatable foods - ABSTRACT Hyper-palatable foods (HPF) are highly rewarding and often consumed in excess. HPF contains combinations of palatability-inducing macronutrients (e.g., fat and sodium) at thresholds that do not occur in nature. The macronutrient combinations produce an artificially rewarding eating experience (beyond what a single macronutrient produces alone), leading to excess intake. Similar to the effects of substances such as alcohol and nicotine, HPF can induce neuroadaptive changes in the brain, yielding hyper-sensitivity to HPF cues in the environment (sensitization), compulsive HPF use, and use despite physical and psychological consequences. Thus, HPF may be best conceptualized as an addictive substance. Understanding the abuse liability of a substance, or the degree to which a substance may be used in excess and lead to negative consequences, is a critical component of regulatory science. However, despite the proliferation of HPF in the US food supply and their substantial public health harms, a major scientific gap is that the abuse liability of HPF is not well understood. The purpose of the study is to conduct a comprehensive abuse liability assessment of HPF using procedures required by the US Food and Drug Administration (FDA) for the testing of potentially addictive products. We will also test whether macronutrients (e.g., fat, sodium) may be modifiable contributors to HPF abuse potential, with the goal of establishing a systematic method to test the addictive potential of HPF using abuse liability framework. A within subjects, double-blind, randomized crossover trial will test the abuse liability of a commonly consumed HPF (potato chips), which contain a trifecta of elevated fat, sodium, and starchy carbohydrates. Full dose HPF (potato chips) will be compared with a negative control low in fat, sodium, and carbohydrates (Jicama root vegetable chip, baked). In addition, modified ‘dose’ chips with one macronutrient removed (fat or sodium) will be tested to examine readily modifiable macronutrients that may reduce HPF reinforcer potency. Consistent with FDA requirements, an acute dose effects comparison will be used to examine the acute subjective effects of HPF, and the reinforcer potency of full dose HPF and modified doses will be tested using behavioral self-administration and food purchase tasks. Currently, HPF are considered foods, alongside whole foods found in nature (e.g., apple). However, HPF effects on neurobiology and behavior may more strongly resemble those of addictive substances than whole foods. Evidence regarding the abuse potential of HPF should inform our conceptualization of HPF, and the potential need for FDA regulatory action. The findings of the proposed study may indicate whether HPF should be conceptualized as a food or addictive substance, and regulated accordingly.
