Psychology of Eating and Drinking

Introduction

• The course is about the psychology of eating and drinking.
• Instructor is Dick Stevenson ([email protected]).
• Tutorials start next week.
• Students should attend the same tutorial each week, if possible.
• Obtain the course handbook from iLearn.
• The handbook includes the course timetable and essential info.

Why Study Feeding and Drinking?

• Essential for survival.
• Key elements of behavior are shaped by evolution.
• Ingestion has shaped color vision, food preferences, weight gain tendencies, and bipedal movement, gut and tooth design, and facial structures.
• Understanding this behavior is vital for several reasons, including malnutrition, undernutrition in developing countries, and obesity in developed countries.

Why Study Feeding and Drinking? (Continued)

• 1.2 billion people globally are undernourished.
• 1.2 billion people in developed countries are overweight or obese.
• These health disparities are due to a variety of biological, psychological, social, and economic factors.
• 15% of adults in the West are dependent on alcohol.

Why Study Feeding and Drinking? (Continued 2)

• Alcohol-related deaths exceed 100,000 annually in the U.S.
• Factors causing addiction to processed foods need investigation.
• The effects of withdrawal from sugar in mice.
• Eating disorders, especially anorexia, are the most lethal psychiatric conditions and affect ~1-2% of college-age women in the West.

Answers?

• Critical questions to consider regarding eating and drinking.
• Why do we choose to eat some things versus others?
• How do we perceive food and drink?
• What societal factors influence ingestion?
• What economic factors govern eating and drinking patterns?

Course Structure

• The course will examine the fundamentals of ingestion.
• Topics include energy metabolism, food types, the digestive system, water balance, and eating/drinking strategies across species.

Then...

• Future topics cover the perception of food and drink, thirst, food-related drugs, food preferences, food taboos, the psychobiology of food intake, the food system (farm to table), and issues related to obesity, starvation, eating disorders, body image, and dieting.

Things You Need To Know

• Lectures are online via Echo360.
• Videos/films are supplemental and not part of the exam.
• A review/question session is scheduled for the last week's tutorials.
• All tutorial sessions take place online via zoom.
• The course handbook contains vital info.

Things You Need To Know (Assessment)

• The course has a 50% multiple-choice end-of-semester exam.
• The exam covers lecture material and Logue's course textbook.
• The remaining 50% is a research project, whose details are explained in the handbook.

Energy Metabolism

• Food's fundamental purpose is to provide energy.
• The body converts this chemical energy into mechanical and electrical energy (used by muscles and nerves, respectively), heat, and other forms.
• Key constituents for energy are carbohydrates, fats and proteins.

Main Metabolic Pathways

• Principal methods for generating energy (in red) are glycolysis, aerobic Krebs' cycle, and anaerobic lactic acid cycle.
• Principal methods for energy storage (in green) are shown.

Measuring the Energy in Food

• The measurement used is the kcal (kilocalorie).
• One kcal is the energy needed to raise 1 liter of water by 1 degree.

What Are the Body's Energy Needs?

• Basal metabolic rate (BMR) is the energy expended at rest.
• BMR comprises about 70–80% of your daily total energy expenditure.
• BMR includes bodily functions such as: cellular physiology (ions pumps), breathing, blood circulation, and protein synthesis.
• Daily caloric needs vary by gender, weight, activity levels, pregnancy, muscle mass and other factors

Calculating Energy Needs

• BMR is a base calculation on which additional requirements for daily activities are built up.
• There are many ranges of activity from sedentary to high activity.
• Daily dietary requirements vary widely depending on a person’s physical activity, gender, age and other variables.

Consequences

• Dieting is a widespread method of weight-loss that may be hazardous to health.
• In some historical cases, deliberate starvation led to extreme health risks amongst a populace.

Carbohydrates-Types and Function

• Simple forms include monosaccharides (e.g., glucose, fructose) and disaccharides (e.g., sucrose, lactose).
• Complex forms include polysaccharides (e.g., starch, cellulose).
• Function primarily provides energy.

Fats-Types and Function

• Fats are also known as triglycerides.
• Different fatty acid tails on the glycerol molecule result in saturated, monounsaturated, polyunsaturated (omega 6/3) fats and trans-fat.
• Function include structural (nerves), hormone synthesis, and storage of energy.

Protein-Types and Function

• Proteins are made up of amino acids.
• Some amino acids are essential (not produced by the body) and must be obtained by consumption.
• Functions are tissue maintenance, enzyme/hormone synthesis, and fluid balance.

Micronutrients-Vitamins

• These are essential nutrients but needed in small amounts.
• There are fat-soluble (e.g., A, D, E, K) and water-soluble vitamins (e.g., C, B vitamins).
• Essential for many metabolic pathways.

Micronutrients-minerals

• Minerals are essential, but needed in small amounts for normal body function.
• Examples include calcium, sodium, potassium, iron, iodine, magnesium, and other micronutrients.

Human Digestive System

• Digesting food is the function of the digestive system.
• Major organs include the stomach, intestines, and accessory organs (liver, pancreas, gallbladder).
• Food undergoes mechanical and chemical breakdown by enzymes.

Human Digestive System-Anatomy

• The digestive system consists of the mouth, pharynx, esophagus, stomach, small intestine, large intestine and accessory organs such as the pancreas, gallbladder and liver.

Small Intestine (SI)

• Most chemical absorption happens in the small intestine.
• The small intestine has a large surface area for absorption.

Large Intestine

• The large intestine absorbs water, forms feces, and houses gut bacteria that form vitamins.

Water Balance

• Water is essential for all bodily functions.
• The body loses water through breathing, sweating, and urination.
• Water balance is an integral part of energy release and regulation of temperature.

Conclusion

• The lecture covered topics related to ingestion.
• Future lectures will focus on issues related to digestion.

Feeding Strategies in Animals

• Appetites are the psychology of eating and drinking in animals
• Introduction to diverse strategies used by animals in acquiring food.

Adaptive Radiation

• The process where living things change and diversify, with an example of a clam being a great subject.
• Feeding strategies are influenced by the necessity to find food, in different environments

The Need for Food

• Animals need food, for energy, and reproduction.
• Food scarcity is a serious problem even in more developed countries today.
• Many people still face starvation worldwide (a serious problem even in our time).

What Constraints Feeding Strategies?

• The animal's size, genetic predisposition, and environment all play a role in a species' feeding strategy.
• Animals have developed specific strategies to acquire food, in a variety of habitats.

Classifying Feeding Strategies in Animals

• Common feeding strategies are herbivory, carnivory, parasitism, and omnivory, each with specific characteristics and adaptations.

Feeding in Herbivores

• Characteristics of herbivores include constant eating, long digestive tracts, appropriate teeth, a symbiotic relationship with bacteria, and methods for avoidance of predation.
• Grazing is one method of consuming vegetation
• Other herbivores feed on fruit, seeds and leaves.

Herbivore Guts for Grazing

• Herbivores have specialized guts for processing plant material.
• Symbiotic digestion is common.

Flowers, Fruits, and Seeds

• Many animals specialize in eating flowers, fruits, and seeds.
• Behavioral adaptations for consuming these food types include complex cognitive mechanisms, such as seasonal location remembering , to enhance nutrient acquisition.

Hummingbirds

• Hummingbirds are an example of food specialists.
• They have specific anatomical and physiological adaptations for consuming nectar.

Other Herbivores

• Some examples of different types of herbivorous feeding strategies discussed
• Includes plant chewers and suckers, plant burrowers, deposit and suspension feeders, and faeces/rotten vegetation feeders.

Dung Beetles

• Dung beetles are an example of specialized feeders
• They feed on the components of dung from herbivores

Herbivores - Conclusion

• Herbivores have considerable focus on intake control and food choice.
• Few plant species are eaten, although not tiring of this repetitive food intake.

Feeding in Carnivores

• Carnivores primarily eat animals, with considerable focus on hunting and eating-to-capacity when prey is abundant.

Carnivore Guts

• Animals with high meat intake have different digestive strategies, with shorter guts than herbivores.

Types of Predators

• Omnivores hunt a wide range of prey, in various ways.
• Predators like sea-lions and leopard-seals have hunting patterns to catch penguins and other prey.

Filter Feeders

• Filter feeders are an unusual adaptation
• Whales are an example

Stalking-Leopard Seals

• Leopard seals are well adapted to ambush and hunting penguins or similar prey.

Stealth Feeding-Vampire Bats

• Vampire bats are adapted to finding and consuming prey in stealth.

Carrion-The Vulture

• Vultures scavenge on dead animals (carcass)

Carnivores - Conclusions

• Carnivores eat few meals, in contrast to herbivores.
• Carnivores have hunger and satiety, but generally their eating habits are different to humans

Feeding in Parasites

• Parasites need their host for optimal survival, and development and transmission.
• Tapeworms are parasites notable for their sophisticated lifecycle.
• Examples like humans and tapeworms illustrate parasitism

Omnivores

• An omnivorous diet is based on both animal and vegetable foods.
• Omnivores such as cockroaches, rats and humans are flexible and have widely different eating practices.

Advantages

• Omnivores have flexible diets, which allow them to adapt quickly to environmental changes, scarce resources and changing abundance.

Disadvantages

• Omnivores face difficulties in determining if consumed food is safe.
• Food supplies including insects, plants, and sea food may expose omnivores to toxins and toxic food.

Consequences

• A lack of behavioral flexibility to ascertain or discern safe food options may cause poor health.
• This is true of all strategies for acquiring food in widely diverse environments.

Conclusions

• The lecture presented many strategies animals have for obtaining and processing food.
• Considerations include sensory input and behaviors.