Nature-Related Odors Influence Stress and Eating Behavior: A Laboratory Experiment With Pine and Grass Volatiles

Before and after Trier Social Stress Test, 91 participants (18–50 years, 67% women) inhaled one odor during 10 min: Scots pine, grass (=cis-3-hexenol), or control (=demineralized water). Group differences were tested on repeated measurements of stress (affect reports, salivary cortisol and heart rate variability) and eating behavior (food choice and craving). Both nature olfactory exposures improved some stress outcomes. Both were associated with lower cortisol in non-stress conditions, but only grass odor was more beneficial for negative affect decrease after stress. No effect on heart rate variability was seen. Some contradictory findings were present for eating behavior. In non-stress situations, grass odor increased vegetable preference, while the pine odor group had higher sweet high-fat snack preference. Grass odor was also reported to induce healthier food choices. During stress recovery, both pine and grass odor groups had higher preference to sweet high-fat snacks.