Week 5 part 2

Controls of Food Intake

• Hunger can be a poor predictor of food intake as people may confuse arousal or anxiety for hunger.
• Objective measures like amount consumed, eating rate, and food types selected are used in experimental studies to measure food intake.
• Food intake can be hunger-driven or satiety-driven, with satiety-driven intake being observed in time-blinded humans.
• Short-term and long-term energy needs are crucial in managing food intake, especially for small mammals like mice.
• The control of eating is complex and involves biological and psychological factors, with no grand theory.
• Biological controls of appetite and psychological controls of appetite are important recurring themes in food intake.
• Stomach contractions were historically thought to cause hunger, but more sensitive measurements reveal a weak relationship between contractions and hunger.
• Environmental cues associated with food, such as sounds, smells, and sights, can trigger hunger and influence eating behavior.
• These cues likely work through associative learning between the cue and prior episodes of ingestion, similar to Pavlov's experiments with dogs.
• The level at which environmental food cues affect behavior and drive eating is not fully established.
• Thirst, which only has one key stimulus - water - still utilizes multiple mechanisms, making food a more complex stimulus.
• There are three important and recurring themes in the control of eating: biological controls of appetite, psychological controls of appetite, and central controls (CNS factors) versus peripheral/environmental controls.

Peripheral Factors Affecting Food Intake

• Portion size significantly influences the amount of food consumed unconsciously.
• Larger packets of food lead to larger serves, and portion sizes have increased in recent years.
• The greater the choice of foods available, the more one will typically eat due to sensory specific satiety.
• Making food more accessible increases consumption; people eat more if no extra effort is needed to obtain the food.
• Time serves as a cue to eating, and meal times are to some extent social constructs.
• Meal sizes increase and intermeal intervals decrease across the course of a day in American participants.
• Evidence suggests that ambient temperature and temperature regulation affect appetite and food intake.
• In long-term studies, the amount of food consumed consistently increases in the fall as winter approaches.
• The number of people present when eating is the most powerful peripheral factor promoting food intake.
• Social facilitation effects are most pronounced for family members and friends, leading to increased food consumption.
• TV viewing can increase food intake via mechanisms similar to social facilitation, especially if the TV show is moderately distracting.
• TV viewing can trigger eating via associative learning, and the effects on food intake are most pronounced if the TV show is moderately distracting.