Stephan Guyenet: The Hungry Brain

Question 1

What causes overeating and obesity? (Also the Theme of “The Hungry Brain”)

Answer 1

A mismatch between ancient survival circuits in the brain and an environment that sends these circuits the wrong messages. (p5)

Question 2

What proportion of deaths among older US adults are linked to excess weight?

Answer 2

Up to one-third. (p11)

Question 3

What is the energy balance equation?

Answer 3

Change body energy = energy in - energy out (p12)

Question 4

What is the primary reason that some foods are more fattening than others?

Answer 4

They coax us to eat more calories. (p13)

Question 5

How many more calories per day did people eat in 2005 versus 1975?

Answer 5

218 calories / day. (p14)

Question 6

How many fewer calories per day must you eat for every pound you want to lose?

Answer 6

10 calories / day. (p16)

Question 7

What’s the most effective way to get a normal rat or mouse to overeat? What’s the name of the diet?

Answer 7

Feed them palatable human foods: the cafeteria diet. (p19)

Question 8

What is “opportunistic voracity?”

Answer 8

When a variety of free, tasty foods are available, people will overeat. (Researcher: Eric Ravussin) (p21)

Question 9

Why do scientists compare lamprey brains with human brains?

Answer 9

Because they are our most distant vertebrate relatives; their ancestors diverged from our own some 560 million years ago. (Researcher: Sten Grillner) (p23)

Question 10

What decision-making apparatus is in both lamprey and human brains?

Answer 10

The basal ganglia (p26)

Question 11

What three things must an effective selector have?

Answer 11

1. Choose one option
2. Choose the BEST option
3. Select decisively among options
   (p25)

Question 12

What is the portion of the basal ganglia that receives most incoming signals from other parts of the brain?

Answer 12

The striatum. (p26)

Question 13

Ultimately, what does the basal ganglia choose?

Answer 13

Which behavior gets access to the muscles and turns away the rest (p26)

Question 14

What does the striatum do?

Answer 14

The striatum receives “bids” from other brain regions, each of which represents a specific action, and selecting the strongest bid (p26-27)

Question 15

How much of our body weight does the brain represent, and how much energy does it use?

Answer 15

2% of bodyweight, up to one-fifth of energy (p29)

Question 16

What is the evolutionary process that takes something that already exists and finds a new function for it?

Answer 16

Exaption. (Coined by Sten Grillner and Marcus Stephenson-Jones) (p31)

Question 17

What do the Basal Ganglia decide in addition to how to move?

Answer 17

How to feel, what to think, what to say, and what to eat (p32)

Question 18

When do we become aware of bids?

Answer 18

Only AFTER they’ve been selected (p36)

Question 19

What is the fundamental spark that sets the whole behavioral cascade in motion?

Answer 19

Motivation (p40)

Question 20

What is learning?

Answer 20

The process of acquiring new knowledge, skills, movement patterns, motivations, and preferences, or reinforcing those that already exist (p41)

Question 21

What is required to start with in order to learn?

Answer 21

A goal (p41)

Question 22

What goals are the fundamental drivers of motivation and learning?

Answer 22

To eat, drink, have sex, be safe and comfortable, and be liked. (p42)

Question 23

What are the three levels of our decision-making process shaped by learning?

Answer 23

motivational, cognitive, and motor (p43)

Question 24

What happens when behavior meets a goal?

Answer 24

The behavior is REINFORCED (p43)

Question 25

What must happen for reinforcement to occur?

Answer 25

There has to be a teaching signal that changes the activity of the basal ganglia loops based on experience (p44)

Question 26

What brain chemical is the essence of reinforcement?

Answer 26

Dopamine (p44)

Question 27

How does dopamine teach us how to feel, think, and behave?

Answer 27

When you accomplish a “goal” like eating a cheeseburger, dopamine is released in short bursts that reinforce our hardwired goals–whether or not our conscious, rational brains support them. (p46)

Question 28

Is dopamine a “pleasure” chemical?

Answer 28

No. Dopamine in the “learning chemical.” Endorphins are the “pleasure chemicals.”

Question 29

What are the most-reinforcing foods?

Answer 29

Foods with the highest caloric density (p49)

Question 30

What is the most-frequently craved food among women?

Answer 30

Chocolate (p56)

Question 31

What is the key to controlling cravings?

Answer 31

Control food cues in your personal environment (p57)

Question 32

What is “food reward”?

Answer 32

The response we have to foods depending on how reinforcing, motivating, and palatable they are.

Question 33

What happens to lean and obese people are fed a liquid diet?

Answer 33

Lean people maintain the same weight; obese people choose to eat dramatically fewer calories and rapidly lose weight (p59-61) (Research: Annals of the New York Academy of Science, 1965)

Question 34

What is “habituation?”

Answer 34

The more we’re exposed to a stimulus within a short period of time, the less we respond to it (p62)

Question 35

What is “sensory-specific satiety”?

Answer 35

Fullness (satiety) only applies to foods that have similar sensory properties (sweet, salty, sour, fatty) to the ones we just ate (p62) (Barbara Rolls 1981)

Question 36

What is the Relative Reinforcing Value of Food [RRV (food)]

Answer 36

A measure of how hard someone is willing to work for food (p66) (Researcher: Leonard Epstein University at Buffalo NY)

Question 37

What is “impulsivity”?

Answer 37

A peso’s ability–or lack thereof–to suppress or ignore basic urges that are beyond conscious control. It’s the opposite of what we commonly call self-control. (p67)