Health Psychology - PowerPoint Presentation

Slide1

Health Psychology

Spring 2013Slide2

Objective

2.3 (EQ

):

Discuss factors related to overeating and the development of obesity.Slide3

Prologue Notes:

Distinguish between obesity and overeating (to assist you in developing your essay)

Be prepared to discuss biological, cognitive and social aspects of obesity and overeating.

Evaluate the aspects that you have presented. Slide4

Understanding Obesity

According to the

World Health Organization

(WHO),

obesity

is a medical condition in which excess

body

fat has accumulated to the extent that it may have an adverse effect on health and is a

major

preventable

cause of death

worldwide. Slide5

Biological factors that influence obesity

There are a number of

physiological theories of obesity.

The strongest physiological theory is associated with genetic predispositions. Research shows that overweight and obese parents are usually 40% more likely to have overweight or obese children.

On the other hand, parents who have normal BMIs are more likely to have children with low BMIs.Slide6

Biological factors that influence obesity

The

gene that has been most closely related to overeating is the FTO gene

(Fat mass and obesity-associated

protein) found on chromosome 16.Slide7

Biological factors that influence obesity

A UK research team, led

by

Dr

Andrew

Hattersley

of Peninsula Medical

School,

have discovered a gene variant that occurs in over half of people of European descent that they think helps to

regulate the amount of fat in the body

.

The scientists discovered the gene, known as FTO, in a study of 2,000 diabetics when they were doing a genome-wide search for susceptibility to type 2 diabetes.

They found there was a strong link between the FTO variant and body mass index (BMI).Slide8

Biological factors that influence obesity

A person with two copies of the FTO variant is likely on average to weigh

6.6 pounds

more than a person who does not have the FTO variant at all, and if they have only one copy they are likely on average to weigh

2.6 pounds

more

.

What does this mean??? Are genes the cause of obesity?Slide9

Biological factors that influence obesity

The gene seems to help write the genetic code passed down through the evolutionary process that tells the body to store fat cells (which would be necessary for survival in times of scarcity)

What does animal experimentation tell us about this gene?

Research by

has

shown that rats with inactive FTO hormones show an increased metabolism, lower levels of BMI, and a significant reduction in adipose (fat) tissue.

Thus, laboratory studies are beginning to suggest that this hormone partially holds the key to fat storage. Slide10

Biological factors that influence obesity

Researchers in labs and institutes around the world are peering into the brain to understand the regions where appetite is perceived and satisfied, and pinpointing the receptors on cell surfaces that keep us hungry or get us sated.

They're

studying the neural wiring of the stomach and intestines, as well as the operation of the

brain

that drive our appetite, to track how

“full” signals

are sent and determine why they sometimes get lost. 

Thus, overeating can have a physiological root wherein the brain is telling the body that it is hungry (even after eating). Slide11

Biological factors that influence on overeatingSlide12

The Hunger Center

The hypothalamus is responsible for a variety of biological functions within your body. The hypothalamus is the body's main regulator of

homeostasis

. The homeostasis of your body is critical. Homeostasis is defined as the production and maintenance of a stable internal environment.

This includes feeling full after you eat. Slide13

The Hunger Center

The hypothalamus has

three main regions

that have been scientifically associated with hunger, including the

lateral,

ventromedial

, and

paraventricular

hypothalamus.

These

regions have been correlated with receptors for certain chemical messengers that signal hunger. Slide14

The Hunger Center

Lateral Hypothalamus

: This region of the brain is associated with

hunger recognition.

Ventromedial

Hypothalamus:

This nuclear region is involved with the

recognition of the feeling of fullness.

Paraventricular

Hypothalamus:

This nuclear region is involved with the

regulation of hunger.Slide15

The Hunger Center

It takes time for the body to recognize that you have eaten and for

the feeling of hunger to go away.

Eating

too quickly

may cause you to eat more food over the same period of time as eating

slowly

and allowing your body to feel "full"Slide16

The Hunger Center

In general,

cravings

for pleasure foods

indicate

low

or

depleted dopamine

levels

.

Cravings

for energy food indicate low serotonin

levels. Lack of sleep, restricting important nutrients in your diet ,

environmental

toxins, and taking certain medications can also deplete the

amount

of neurotransmitters in your

system-

which all in turn can influence overeating.

Lack

of willpower is actually a biochemical deficiency of

neurotransmitters in

the

Hypothalamus.

The deficiency occurs especially when

you

are under a lot of stress.Slide17

The Hunger Center

Dopamine

and

serotonin

are the most important neurotransmitters for

appetite

control.

High

levels of these messengers satisfy your appetite, while low levels

cause

you to become hungry or to overeat.Slide18

The Hunger Center

An international team led by

Dr.

Tamas

Horvath

, neurobiology professor and chair of comparative medicine, and researchers in Germany identified

neurotransmission in

the brain

responsible

for hunger regulation.

The

study, published this month in Nature Neuroscience, found that

one region suppresses appetite while the other promotes it.Slide19

The Hunger Center

To find

direct

evidence of the influence of these neurotransmitters, the research team depleted and increased the levels of these neurotransmitters in mice. More specifically, the

discovery was made by destroying cells in the

hunger-region

of mice.

These

animals demonstrated

reduced sensations of

hunger

and were eventually diagnosed with

acute anorexia

, while weight gain and obesity were observed in mice whose appetite suppressing neurons were attacked.Slide20

Stress and Overeating

There is much truth behind the phrase "stress eating." Stress, the hormones it unleashes, and the effects of high-fat, sugary "comfort foods" push people toward overeating.

Researchers

have linked weight gain to stress, and according to an American Psychological Association survey, about one-fourth of Americans rate their stress level as 8 or more on a 10-point scale

. Thus, in a culture of high stress, you will also find high levels of overeating and obesity (think of stress as the fraternal twin of overeating). Slide21

Stress and Overeating

In the short term,

stress can shut down appetite

.

The hypothalamus

produces

corticoid hormones

(which secrete cortisol into the blood),

which suppresses appetite.

The

brain also sends messages to the adrenal glands

to

pump out

(

also known as adrenaline).

Which

temporarily

puts eating on hold.Slide22

Cognition and Overeating

Our cognitions (emotions , schemas, perception, etc.) all play a key role in why we eat, when we eat, what we choose to eat, and what we find pleasurable.

Cognitive Psychologists have began to investigate the role of cognitive processes in overeating and obesity and have found very significant cognitive influences. Slide23

Cognition and Overeating

Healthy eating habits and

exercising regularly takes

cognitive discipline

and motivation.

Both are difficult to

measure

and to

instill

into others.

Education

is required to show people the effects of their lifestyle on their health.

Cognitive

dissonance

is

needed to change

behavior. Perception

can be influenced by a number of factors.

Many people who overeat and suffer from obesity fail to understand the

power of emotional eating, schemas for what to eat, and other significant cognitive processes that shape our appetite for food. Slide24

Cognition and Overeating

Reviewing

38 recent studies

into obesity and cognition, researchers from UNSW’s School of Psychiatry found there was a likely “vicious cycle” relationship between

cognition and obesity

, with low performance in planning, reasoning and problem solving

exacerbating

weight gain, which in turn compounds negative influence on the brain via biological mechanisms

.

The meta-analysis showed significant declines in executive decision making, lack of cognitive restraint, emotionally learned eating habits, and other cognitive factors as factors that significantly contribute to overeating (This can be explained in your response). Slide25

Sociocultural

aspects of overeating

Many researchers take in account the importance of culture along with situational factors that influence the development of obesity.

Two key factors include:

The lack of physical activity and eating behavior. Slide26

Conclusion

Things to consider:

What does social research suggest about stress and stressors?

Should there be cultural differences in perceptions of social support?

What are the limitations to only taking ONE approach to stress?