Food Cue Reactivity and Body Weight: Differences in Physiological Reactivity and Cravings Between Overweight and Healthy-Weight Individual

Objective: Obesity is a growing health problem with serious health and psychosocial consequences. Current weight loss treatments are limited in their ability to maintain long-term weight loss. Today's modern environment is saturated with highly palatable, calorically dense foods leading to the overeating of fat- and sugar-rich foods and subsequent weight-gain. Cue reactivity is made up of physiological responses, known as cephalic phase responses (CRPs), subjective craving, and food consumption following food cue exposure. The autonomic nervous system response component of CPRs has been found to be altered in obese individuals. The present study was designed to contribute to the food cue-reactivity literature by investigating the autonomic nervous system processes and responses to palatable food-cues in overweight/obese and healthy-weight adults. Methods: Participants in the study included 50 adults between the ages of 18 and 26 years. Two equal groups of healthy-weight and overweight/obese participants were created based on body mass index (BMI). Data were obtained for each participant in 75-minute sessions using electrophysiological measurements. Participants were guided through a baseline period, food exposure task, and recovery period and reported subjective craving every 30 seconds on a 1-100 scale. Physiological responses, measured continuously, included heart rate, multiple heart rate variability (HRV) parameters marking sympathetic and parasympathetic components, and skin conductance. Results: Repeated measures ANOVAs found increased food cravings during exposure and habituation to baseline levels during recovery for the total sample. During food exposure and recovery increases in Low Frequency HRV, heart rate, and skin conductance were found for the total sample. Decreases in RMSSD, SDNN, High Frequency HRV were found after exposure for the total sample. One-way ANOVAs, with area under the curve (AUC) to represent cue-reactivity, found greater AUC LF HRV in the overweight group. Linear regressions found a positive association between food cravings and skin conductance. Conclusion: The present study found autonomic food-cue reactivity characterized by increasing sympathetic activity and decreasing parasympathetic activity for both healthy-weight and overweight/obese individuals. Results provided limited evidence for the prediction that autonomic cue-reactivity would differ by BMI group. Evidence suggested the presence of altered sympathetic reactivity in overweight/obese individuals. Sympathetically driven CPRs may be subjectively experienced as food cravings, providing support for the cue-reactivity model. Future research should strive to replicate and explore these findings.