Final answer:
An external factor that influences eating behavior is 'eating as a sport,' a cultural and social activity, unlike internal biochemical factors like glucose, insulin, and serotonin. Cultural, economic, and educational factors also significantly impact dietary choices.
Step-by-step explanation:
External Factors Influencing Eating Behavior
An external factor that may influence eating behavior is eating as a sport. Unlike glucose, insulin, and serotonin, which are internal biochemical factors affecting eating behavior, engaging in eating events for sport is driven by external cultural and social factors. Competitive eating competitions illustrate how cultural activities and social settings can directly stimulate or modify eating patterns, often independent of physiological hunger cues.
Cultural and family influences, availability and cost, and education are additional external factors that can profoundly affect eating behaviors. Cultural practices can dictate the types of food consumed, while economic factors such as cost and access to food can also shape dietary choices. Furthermore, education regarding nutrition has the power to influence eating habits and preferences.
Regarding the neurotransmitter serotonin, it is true that it normally has an inhibitory effect on eating, suggesting that it plays a role in promoting satiety and reducing appetite—yet this is an internal factor rather than external.