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Palatability and foraging cost interact to control caloric intake
1Department of Psychology, Brooklyn College of the City University of New York 11210, USA. kackroff@broadway.gc.cuny.edu
Journal of Experimental Psychology. Animal Behavior Processes
|February 13, 1999
Summary
Meal cost influences rats' (Rattus norvegicus) feeding behavior. Increasing food cost reduced intake of palatable foods but not unpalatable ones, suggesting flavor overrides cost when food is less desirable.
Area of Science:
- Behavioral neuroscience
- Animal behavior
- Nutritional science
Background:
- Understanding the factors that regulate meal size and intake is crucial for addressing obesity and eating disorders.
- Previous research has often confounded palatability with nutrient composition and caloric density, making it difficult to isolate the effects of flavor and cost.
Purpose of the Study:
- To investigate the independent effects of food flavor and meal cost on meal size and intake in rats (Rattus norvegicus).
- To determine if palatability or cost is a stronger determinant of feeding behavior when postingestive feedback is controlled.
Main Methods:
- Rats (Rattus norvegicus) consumed flavored liquid diets with varying palatability (unpalatable sucrose octaacetate [SOA], neutral saccharin, palatable Polycose + saccharin [P + S]).
- Liquid diet was infused intragastrically to decouple postingestive feedback from flavor and cost.
- Meal initiation was controlled either by free access or by lever-pressing, altering the cost of obtaining food.
Main Results:
- Rats consumed larger meals with higher caloric intake when drinking palatable fluids (P + S) compared to neutral fluids (saccharin).
- Rats consumed smaller, more frequent meals with lower initial caloric intake when drinking unpalatable fluids (SOA) compared to neutral fluids.
- Increasing meal cost by requiring lever-pressing reduced meal frequency and increased meal size, but did not alter total caloric intake.
- The effect of palatability on meal size was diminished when postingestive feedback was controlled.
Conclusions:
- Flavor and cost independently influence meal size and intake in rats.
- Palatability plays a significant role in motivating feeding behavior, particularly when the cost of obtaining food is low.
- When postingestive feedback is controlled, increasing the cost of food can blunt the response to flavor, suggesting a complex interplay between sensory and postingestive factors in appetite regulation.