Food odors influence behavioral and physiological parameters of human eating behavior

The current food environment continuously exposes individuals to cues of (high energy dense) foods. Several studies have shown that odors can induce appetite and may influence subsequent food choice and perhaps intake. However, research on the latter is contradictory. Therefore, the aim of this study was to investigate the effect of ambient odor exposure on appetite, food intake and salivation. 32 normal-weight young women (age: 24.4±5.2 year; BMI: 21.7±1.9 kg/m2) attended five test sessions, on different days, in a non-satiated state. Each participant was exposed to ambient odors (chocolate, beef, melon and cucumber) in a barely detectable concentration and to a control condition (no-odor exposure). During each condition, at various time points, participants rated appetite for 15 food products, and saliva was collected. After approximately 30 min, ad libitum intake was measured providing a food (chocolate rice, high-energy dense product) that was congruent with one of the odors they were exposed to. Mixed model analyses show that specific appetite was not influenced by odor exposure (p=0.64). However, a significant odor effect on food intake (p<0.05) and salivation (p<0.05) was found. Exposure to odors signalling high-energy dense products increased food intake (244 ± 23g) compared to the control condition (207 ± 25g; p<0.05). In line with these results, salivation was increased significantly during chocolate and beef exposure (both 0.49 ± 0.05g) compared to the control condition (0.41±0.05g; p<0.05). In conclusion, exposure to food odors seems to drive behavioral and physiological responses involved in eating behavior. This could have implications for steering food intake, and consequently the energy intake, influencing the nutritional status of people. This study was funded by NWO (The Netherlands Organization for Scientific Research), Veni grant no. 451-11-021 awarded to SB.