PY0547_Week 7_Feeding & Obesity(1)
Page 1: Introduction
Course: PY0547 Psychobiology I
University: Northumbria University Newcastle
Lecture Topic: Feeding and Obesity
Week: 7
Instructor: Dr. Fiona Dodd
Page 2: Overview of Obesity
General insight into obesity as a significant health concern.
Page 3: Complexity of Weight Management
Importance of understanding factors beyond just exercise in managing weight.
Finlayson et al. (2009): Identified 'compensators' who increase caloric intake post-exercise, favoring high-fat, and sugary foods.
Fothergill et al. (2016): Examined former contestants from The Biggest Loser reality show found many regained lost weight over 6 years.
Notable results:
Slowed metabolic rates observed longitudinally.
The body adapted by decreasing energy expenditure.
Page 4: Psychological Influence on Eating
Suggests there is a mental aspect to eating behaviors and hunger regulation.
Page 5: Biology and Psychology of Feeding
Understanding contributing factors to hunger and appetite.
Biological Aspects:
Role of brain regions, hormones, and neurotransmitters.
Psychological Aspects:
How external cues influence eating behavior.
Psychobiology:
Examines consequences of ignoring internal hunger cues, leading to issues like obesity.
Page 6: Biological Pathways of Hunger
Homeostatic vs. hedonic systems in hunger regulation.
Key regions involved:
Homeostatic Pathway: Paraventricular nucleus, arcuate nucleus, etc.
Reward Pathway: Prefrontal cortex, nucleus accumbens, etc.
Hormones: Leptin, Ghrelin, Cortisol, etc.
Adipose Tissue: Involved in energy storage and metabolism.
Page 7: Hunger Regulation Mechanisms
Homeostatic Control
Neuropeptide Y (NPY): Induces hunger in response to low glucose.
Ghrelin: Triggers hunger and is influenced by insulin levels.
Orexigenic Neurons: Communicate information about hunger and satiety through neuropeptides.
Page 8: Satiety Mechanisms
Leptin: Secreted by adipose cells signaling fullness.
Peptide YY: Released post-meal proportional to caloric intake, inhibiting NPY.
Both hormones play a role in reducing hunger and boosting metabolism.
Page 9: Understanding Hunger and Satiety Hormones
Orexigenic Hormones: Increase appetite (e.g., Ghrelin).
Anorexigenic Hormones: Decrease appetite (e.g., Leptin).
Page 10: Insulin and Glucagon Functions
Post-meal: Insulin is released to help store energy; facilitates amino acid and fat transport.
Fasting: Glucagon mobilizes stored glucose and fat for energy.
Role of pancreas, liver, and food digestion processes in energy regulation.
Page 11: Physical Sensations of Hunger
Cannon and Washburn Study (1912): Examined the stomach's role in hunger pangs.
Used a balloon to monitor stomach contractions correlating with reported hunger.
Page 12: Mechanism of Hunger Messages
Stretch Receptors: Signals sent via the vagus nerve to brain areas overseeing hunger.
Pathway: Stomach → Nucleus of the Solitary Tract → Hypothalamus.
Page 13: Chemical Messaging in Hunger
Studies by Koopmans (1981) and Davis et al. (1969): Investigated stomach chemistry influence on hunger and satiety.
Blood transfusions from fed rats led to cessation of hunger in hungry recipients.
Page 14: Sensory Influences on Eating
Taste and Palatability
Rolls et al. (1981): Studies on how food taste affects consumption.
Preference decrease after initial consumption emphasizes the role of variety in meal selection.
Page 15: Learned Taste Aversion
Bernstein and Webster (1980): Chemotherapy patients showed aversion to flavors associated with treatment, highlighting the capacity for quick learned aversion.
Page 16: Consumption Bias due to Package Size
Wansink and Kim (2005): Showed large vs. small food packages significantly influence consumption, even when food palatability is low.
Page 17: Social Factors in Eating
de Castro et al. (1989): Evidence showing that eating with others leads to larger meal sizes and increased overall intake.
The presence of more individuals correlates positively with meal size due to social facilitation.
Page 18: Environmental Influences
Aesthetics like package size and plate shape significantly impact consumption behaviors, contributing to overeating patterns.
Li et al. (2009): Noted negative associations between fast food proximity and obesity rates.
Page 19: Psychobiological Implications of Obesity
Definition of obesity as abnormal or excessive fat accumulation (WHO): BMI > 30.
Page 20: Non-Homeostatic Feeding
Psychobiological Pathway: Examines how reward pathways adapt when intake exceeds energy expenditure.
Exploration of overeating as an addiction model involving brain structures like the nucleus accumbens.
Page 21: Dopamine Receptors and Obesity
Wang et al. (2001): Studies suggesting the inverse relationship between BMI and dopamine D2 receptor density.
Evaluates whether overeating impacts receptor density or if pre-existing conditions predispose to it.
Page 22: Hormonal Dysregulation in Obesity
Discussion of the effects of leptin resistance, abnormal ghrelin, cortisol levels, and insulin resistance in the context of obesity.
Page 23: Societal Impacts of Stigmatization
Jackson et al. (2016): Research linking perceived weight discrimination with increased cortisol levels, particularly in severe obesity cases.
Societal stigma's complex role in obesity and related metabolic responses.
Page 24: Additional Resources
Links to support organizations for further learning and essay writing assistance via Blackboard resources.
Course Overview on Feeding and Obesity
Course: PY0547 Psychobiology I
University: Northumbria University Newcastle
Instructor: Dr. Fiona Dodd
Key Insights:
Obesity: A significant health concern characterized by abnormal fat accumulation (BMI > 30).
Weight Management: Important factors include calorie intake post-exercise; evidence from studies shows challenges in maintaining weight loss and the body's adaptive metabolic responses.
Psychological and Biological Influences: Hunger and satiety regulated by hormonal pathways; leptin and ghrelin play crucial roles. Psychological factors, including social influences and learned aversion, impact eating behaviors.
Environmental and Social Aspects: Meal size influenced by social settings and food aesthetics; proximity to fast food linked to obesity rates.
Dopamine and Hormonal Dysregulation: Research suggests a connection between obesity and dopaminergic activity, along with implications of leptin resistance and cortisol levels.