- Leann L Birch: The Center for Childhood Obesity Research, The Pennsylvania State University, University Park, PA, USA.
What has become familiar tends to be preferred while the unfamiliar is avoided. Additionally, liking is impacted by associative learning processes where new stimuli become liked via repeated pairings with familiar, already-liked stimuli. In addition to the ability to learn to like new foods and flavors, infants bring genetic taste predispositions to the table, including an unlearned preference for sweet and salty tastes and a tendency to reject bitter and sour tastes. When diets were plant based, unlearned preferences for sweet and salty tastes promoted intake of foods that were relatively rare in nature but were good sources of essential nutrients; the presence of the preferred basic tastes in food no longer predicts scarce nutrients. Our 'obesogenic' dietary landscape is replete with sweet and salty foods that are energy dense, inexpensive, and exquisitely tuned to our genetic taste predispositions. In the current environment, early familiarization and associative learning can result in unhealthy diets and may promote obesity risk, but we suggest applying what we know about how food liking is learned to promote healthier diets. We review classic and current evidence demonstrating how familiarization and associative learning may be used to promote the intake of initially rejected foods like vegetables within an obesogenic context.