Hunger Motivation Module 53
Hunger Motivation Module 53
Learning Targets
053-1 Describe the physiological factors that produce hunger.
053-2 Discuss cultural and situational factors that influence hunger.
53-3 Discuss how we are affected by obesity and the factors involved in weight management.
Quotes on Hunger
"Hunger is the most urgent form of poverty." - Alliance to End Hunger, 2002
"The full person does not understand the needs of the hungry." - Irish proverb
Overview of Hunger Motivation
Hunger is a strong physiological need, as illustrated by Ancel Keys' 1950 study on semistarvation:
Study Design: 200 men were fed normally for three months, then food intake was halved for 36 participants.
Physical Effects: The men became listless and apathetic as the body conserved energy, stabilizing at weights 25% below their original weights.
Psychological Effects: Reflecting Maslow's hierarchy of needs, the subjects became obsessively focused on food, discussing it incessantly and expressing little interest in sex or social activities.
Participant Quote: “The most interesting part of any show is when people are eating.”
Quote by Dorothy Dix: “Nobody wants to kiss when they are hungry.”
Implication: Powerful motives can dominate focus and behavior, such as hunger or sexual arousal.
The Physiology of Hunger
53-1 What physiological factors produce hunger?
Homeostatic System: Maintains normal body weight and adequate nutrient supply.
Washburn and Cannon Experiment (1912):
Method: Washburn swallowed a balloon to measure stomach contractions, correlating these with self-reported hunger pangs.
Findings: Consistent stomach contractions were associated with subjective feelings of hunger.
Do Hunger Pang’s Necessarily Exist?
Experiments on rats demonstrated that hunger continues even when stomachs were removed, suggesting other mechanisms also trigger hunger.
Body Chemistry and Brain
Caloric Intake Regulation:
Body automatically regulates caloric intake via blood sugar levels and various hormones.
Key Hormones:
Insulin: Secreted by the pancreas, decreases blood glucose levels.
Ghrelin: Secreted when the stomach is empty, signaling hunger.
Your brain monitors blood chemistry to trigger hunger when glucose levels drop.
Neural Control Centers
Hypothalamus:
Integrates signals related to hunger through neural centers that secrete either appetite-stimulating or appetite-suppressing hormones.
Set Point: The hypothalamus helps maintain a specific body weight set point, influencing food intake and metabolic rates.
** metabolic rate:** The body's resting energy expenditure; varies with weight changes.
Hunger Hormones
Ghrelin: Hunger-arousing hormone from the stomach.
Orexin: Hunger-triggering hormone from the hypothalamus.
Insulin: Regulates blood glucose, suppresses hunger.
Leptin: Released by fat cells; indicates fat levels, shows metabolism and hunger levels.
PYY: Derived from the digestive tract, signals satiety to the brain.
Psychology of Hunger
53-2 What cultural and situational factors influence hunger?
Memory and Eating:
Studies show that in cases of amnesia, individuals consumed meals shortly after each other due to lack of memory of previous meals. Hunger can thus be driven by memory as well as physiology.
Taste Preferences
Cultural Influences: Preferential choices differ widely across cultures (e.g., whale blubber in Alaskan natives, guinea pig in Peru).
Biological Drives: Genetic predisposition influences cravings for sweet and salty flavors.
Conditioning of Tastes: Exposure can develop food preferences (e.g., taste aversions after sickness).
Adaptation of Tastes: Certain spices in hot climates inhibit bacterial growth, highlighting historical adaptability of tastes.
Situational Influences on Eating (Ecology of Eating)
Factors Impacting Eating Behavior:
Arousal: High-intensity stimuli (e.g., action movies) can increase intake.
Social Context: People tend to eat more with others due to social facilitation.
Portion Size: Larger servings lead to greater consumption (studies show portion-related intake influences).
Variety: Increased food choices can stimulate higher intake.
Nudging: Environmental changes can promote healthier eating decisions (e.g., fruit placement in food lines).
Understanding Obesity
53-3 How are we affected by obesity, and what factors are involved in weight management?
Obesity Defined: A Body Mass Index (BMI) of 30 or higher; overweight is classified as a BMI of 25 or higher.
Health Implications of Obesity: It is linked to various health risks:
Diabetes, heart disease, high blood pressure, and arthritis.
Psychological effects, including increased depression and bullying.
Obesity Statistics**
Global obesity has nearly tripled since 1975. In the U.S., obesity rates have more than doubled, with child obesity quadrupling.
Many nations report rising obesity rates, influenced by dietary habits and sedentary lifestyles.
Contributing Factors to Obesity
Physiological Factors:
Storing fat has been adaptive historically, evolving as a survival mechanism.
Set Point Theory: Weight drop below set point triggers hunger and decreased metabolism.
Metabolic Resistance: Bodies adapt to lower caloric intake by slowing metabolism, making sustainable weight loss difficult.
Environmental and Behavioral Influences:
Sleep deprivation increases the risk of obesity.
Increased sedentary lifestyles have contributed to weight gain.
Genetic Influences on Weight
Research indicates a strong genetic contribution to individual weight differences, with various genes identified impacting weight regulation.
Practical Tips for Weight Management
Healthy Changes:
Focus on motivation and self-discipline; lifestyle changes are essential.
Incorporate exercise and sufficient sleep to increase metabolism and reduce stress-related eating.
Manage food cues by shopping full and minimizing the presence of tempting foods.
Control portion sizes and aim for less variety in meals to avoid overconsumption.
Avoid binge-eating tendencies that may arise with emotional triggers.