Food Odours Direct Specific Appetite

Olfactory food cues were found to increase appetite for products similar in taste. We aimed to replicate this phenomenon for taste (sweet/savoury), determine whether it extends to energy density (high/low) as well, and uncover whether this effect is modulated by hunger state. Twenty-nine healthy-weight females smelled four odours differing in the energy density and taste they signalled, one non-food odour, and one odourless solution (control), in random order, for three minutes each. Appetite for 15 food products was rated in the following two minutes. Mixed model analyses revealed that exposure to an odour signalling a specific taste (respectively sweet, savoury) led to a greater appetite for congruent food products (sweet/savoury) compared to incongruent food products (savoury p < 0.001; sweet p < 0.001) or neutral food products (p = 0.02; p = 0.003). A similar pattern was present for the energy-density category (respectively high-energy dense, low-energy dense) signalled by the odours (low-energy products p < 0.001; high-energy products p = 0.008). Hunger state did not have a significant impact on sensory-specific appetite. These results suggest that exposure to food odours increases appetite for congruent products, in terms of both taste and energy density, irrespective of hunger state. We speculate that food odours steer towards intake of products with a congruent macronutrient composition.