Ch 12 Hunger, Eating and Health

Many people assume that hunger is normally triggered when energy resources fall

below a prescribed optimal homeostatic level called a set point.

The case of R.H., the man who forgot not to eat, suggests that

B) the motivation to eat a meal does not normally come from the decline of energy resources.

As a consequence of digestion, three different forms of energy are delivered to the body:

lipids, amino acids, and glucose.

Most of the body's energy reserves are stored in the form of

B) fat.

The body stores energy as

A) fats. B) glycogen. C) proteins. D) all of the above

There are ___ phases of energy metabolism.

3

The three phase s of energy metabolism are, in sequence,

cephalic, absorptive, and fasting.

Which phase of energy metabolism is triggered by the sight, odor, or taste of food, or just by thinking about eating?

cephalic phase

The transition between the absorptive and fasting phase occurs when

C) the body stops deriving its energy from the fuels still circulating in the blood from the previous meal.

Insulin promotes the

A) use of glucose as a metabolic fuel. B) conversion of glucose to fat. D) both A and B

Immediately following a meal, glucose levels in the blood do not increase as much as they otherwise might because

insulin promotes the use of glucose by the body

Insulin promotes the

A) conversion of glucose to glycogen and fat. B) use of glucose as the primary source of energy by the body C) storage of glycogen and fat. D) all of the above

During the fasting phase, the body (excluding the brain) cannot use glucose as a metabolic fuel because

insulin levels are low and insulin is needed for glucose to enter the cells of the body.

The conversion of protein to glucose is called

gluconeogenesis

During the fasting phase, most of the energy used by muscles is derived from

free fatty acids released from adipose tissue.

Free fatty acids are the main source of energy for the body (excluding the brain) during

the fasting phase.

During the fasting phase, the main fuel of the brain is

glucose

Although the ___ assumption is engrained in most people's thinking, it is inconsistent with most of the evidence.

set-point

Many people believe that hunger is a product of

energy deficits.

All set-point models have

A) a set-point mechanism. B) a detector mechanism. C) an effector mechanism. D) all of the above

All set-point systems are ___ systems

negative feedback

Negative feedback systems in the body tend to maintain

homeostasis

Set-point negative-feedback systems are one way of maintaining

homeostasis.

Glucostatic theory is to lipostatic theory as

A) glucose is to fat. B) short-term is to long-term regulation. D) both A and B

According to the lipostatic theory,

B) each person has a body-fat set point.

According to the lipostaic theory

B) each person has a body-fat set point C) maintaining fat levels in the body at homeostatic levels is a major factor in the long-term regulation of food intake. E) both B and C

Injections of insulin

. C) trigger eating only if the doses are large enough to produce reductions in blood glucose that are greater than those that would normally occur under typical free-feeding conditions

Consuming a high-calorie drink before a meal reliably

none of the above

Inconsistent with theories that hunger and eating are entirely regulated by set points is the fact that

flavor has a major impact on hunger and eating.

The inability of set-po int theories to account for the basic phenomena of hunger and eating has led to the development of

positive-incentive theories.

The anticipated pleasurable effect of eating a particular food is that food's

positive-incentive value

According to the positive incentive theory, the main cause of hunger in food replete environments is

The presence or anticipation of food

Most humans have a fondness for ___ tastes.

A) sweet B) fatty C) salty D) all of the above

Which of the following influences the positive-incentive value of food?

A) the flavor of the food B) the amount of time since one last ate C) one's previous experiences with the food D) whether or not other people are present and eating E) all of the above

Eating sweet and fatty foods is adaptive for many mammals living in the wild because in nature thes tastes

A) are characteristic of energy-rich foods. B) are often found in association with beneficial vitamins and minerals.

D) Both A and B

Animals learn to

B) prefer tastes that have been followed by an infusion of calories. C) avoid tastes that have been followed by gastrointestinal illness. E) both B and C

Rats have been shown to prefer flavors that

A) they experience in their mother's milk. B) they smell on the breath of other rats. D) both A and B

Animals with a sodium deficiency

D) automatically prefer the taste of sodium salt.

Animals with a sodium deficiency, tend to favor diets rich in sodium because

C) the deficiency produces an immediate preference for the taste of sodium salts.

Animals in the wild tend to eat a balanced diet because they

none of the above

Rats that have lived for several weeks with access to only a single laboratory chow that is devoid of thiamine

C) will often learn to prefer the taste of a new diet that contains thiamine.

According to the text, many people who live in modern industrialized societies have difficulty eating a diet with enough vitamins and minerals because

C) they eat too many different flavors each day for their systems to learn the relation between the flavor of a food and its effects.

Those mammals with ready access to a continuous supply of good food usually eat ___per day

many small meals, or snacks,

People tend to feel hungry

A) at their regular mealtimes, whenever they are.

According to Woods, the hunger that one experiences as a regular mealtime approaches is

the result of the changes occurring in your body in preparation for the homeostasis-disturbing meal.

According to Woods, in the short-term, meals are

homeostasis-disturbing.

According to Woods, the cephalic phase is a period during which

A) physiological changes occur that tend to minimize the homeostasis-disturbing effects of the expected meal

A classic series of conditioning experiments in laboratory rats showed that the initiation of eating can be a consequence of

Pavlovian conditioning to meal-predictive cues

According to the Pavlovian conditioning studies of Weingarten, we are likely to initiate meals when

we are in situations in which we have often eaten before.

Don poured himself half a glass of milk. Because he was thirsty, he added half a glass of water to it. In doing so, Don

halved the milk's nutritive density.

Sham-eating procedures typically reduce caloric intake into the bloodstream during a meal by

A ) 100 % .

Illustrated here is a ___preparation

sham-eating

In sham-eating experiments, the first sham eaten meal of a familiar diet is typically the same size as previous normal meals of the same diet. This suggests that the amount that we eat at a meal is influenced by

our previous experience of the physiological consequences of eating the same food.

Small amounts of food eaten prior to a meal ___ hunger. This is called ___

increase; the appetizer effect

Rats eat ___ when fed ___

more; in groups

Which of increase the in their following produces a substantial increase in the calorie intake of laboratory rats and a significant body weight

offering them a cafeteria diet, rather than their usual single-chow laboratory diet

Cafeteria diets

are those in which several palatable foods are available.

encourages the consumption of a varied diet.

Sensory-specific satiety

As a meal is consumed, there is

A) a rapid decline in the positive-incentive values of the particular tastes that are being consumed. C) a gradual decline in the positive-incentive value of all foods. E) both A and C

6o) Hunger and eating can be induced in satiated mammals by decreasing blood glucose levels with large injections of insulin. However, such large decreases

rarely, if ever, occur in healthy humans or other mammals with ready access to food

According to the dominant hy pothalamic theory of eating in the 1950s and 1960s, hunger is to satiety as the

LH is to the VMH.

The VMH hy perphagia syndrome comprises two phases. In chronological sequence, these phases are the

The dynamic phase and the static phase

The dynamic phase of the VMH syndrome is associated with

B) weight gain. C) lipogenesis. E) both B and C

64) Rats in the static phase of the VMH syndrome

D) increase their food intake following a period of deprivation.

65) Grossly obese rats that are regulating their weights after large bilateral VMH lesions are usually

moderately hyperphagic.

Large bilateral lesions of the lateral hypothalamus produce

A) aphagia B) adipsia. D) both A and B

Evidence suggests that the hyperphagia of rats with large bilateral VMH lesions may result from

increases in insulin release

Evidence suggests that the effects of large bilateral VMH lesions on eating are, in part, caused by damage to the ___ or its connections.

paraventricular nuclei

The idea that the LH is a hunger center has largely been abandoned because

bilateral LH lesions produce severe and general motor disturbances and reduce responsiveness to all kinds of sensory input, not just food.

VMH lesions in rats

A) increase lipogenesis. B) increase insulin release C) reduce lipolysis. D) all of the above

Undermining the theory that the VMH is the satiety center is the fact that selective lesions of the ___ nuclei of the hypothalamus lead to hyperphagia and obesity

paraventricular

One of the first studies of the physiology of hunger was that of Cannon and Washburn ( 1 9 1 2 ) They found that

subjective feelings of hunger are associated with stomach contractions.

73) The conclusion of the 1912 study illustrated here was that stomach contractions are associated with

B) hunger

Human patients who have had their stomachs surgically removed eat

continue to maintain their body weights by eating more meals of smaller size.

In a classic study, a stomach was transplanted from one rat into another and connected to the circulatory system of the recipient. Food was then injected into the implanted stomach. This experiment indicated that

A) the gastrointestinal tract produces a satiety signal. B) food-related chemical signals from the stomach are transmitted through the circulatory system to the brain. D) both A and B

76) Food in the stomach stimulates the release of ___ from the stomach wall

peptides

CCK, bombesin, glucagon, and somatostatin

A) are peptides B) are released from the gut. E) both A and B

Neuropeptide Y, galanin, orexin A, and ghrelin are

hunger peptides.

Both galanin and neuropeptide Y

A) are peptides. B) increase eating. E) both A and B

CCK is to neuropeptide Y as

satiety is to hunger.

Many hunger and satiety peptides have receptors in the

hypothalamus.

___ have been shown to reduce hunger, eating, and body weight in human patients.

Serotonin agonists

People with ___ act as if they are starving.

Prader-Willi syndrome

The set-point theory of body weight regulation is designed to explain

why the weights of adults stay constant.

A major problem with the set-point theory of body weight regulation is that it

cannot explain the increasing prevalence of obesity.

An important health-related implication of the set-point theory of body-weight regulation and hunger is that

The value of each person's set point should be appropriate for her or his good health

It seems clear that warm-blooded animals that have ready access to a variety of palatable foods eat far more than is optimal for their health. Evidence of this point comes from

point A) studies of the superior health of humans who eat substantially less than ot B) experiments on the effects of calorie restriction in many different species. E) both A and B

In one experiment, the caloric intake of mice was reduced from free-feeding levels by up to 25, 55, or 65 % . The benefits of the caloric restriction were greatest in the 65 % group . These benefits included

A) an increased life span. B) a reduced incidence of cancer. C) improved immune responses. D) all of the above

As a person puts on weight, there is

a decrease in the efficiency of energy use

If you were to eliminate 500 calories from your daily diet, you would likely

initially lose weight, but the amount lost each day would decline until a new stable weight was reached.

Diet-induced thermogenesis refers to the increases in body temperature produced by

increases in body fat.

The rate at which resting individuals utilize their energy resources to maintain their basic body processes is

the basal metabolic rate

The level at which the various factors that influence body weight achieve an equilibrium is called the body weight

settling point.

Settling-point models of body weight regulation

A) maintain a loose kind of homeostatic regulation. B) do not have a prescribed set point. C) do not have negative feedback mechanisms that actively correct changes from homeostasis. D) have negative feedback mechanisms that reduce the impact on body weight of changes in consumption

E) All the above

The leaky-barrel model of body weight regulation is a

A) settling-point model B) negative-feedback model. E) both A and B

The leaky-barrel model of body weight regulation

A) is a settling-point model. B) can account for the fact that body weight often remains relatively stable C) can account for the fact that compensatory changes occur to reduce decreases or increases in body weight D) can account for the fact that dieters tend to regain lost weight once they go off their diets. E) all of the above

Which of the following cases can be readily accounted for by the leaky-barrel model, but not by traditional set-point models?

A) A women married a cook, and her weight rapidly increased by 5 kilograms; the added weight stayed, despite her efforts to lose it B) A business executive became a marathon runner, and her food consumption went up while her weight went down and stayed down. C) A dieter changed his lifestyle, he lost 30 kilograms, he never put the weight back on, and he never felt any compulsion to overeat. D) all of the above

Settling-point models of weight regulation can explain why

D) dieters regain lost weight after they go off their diets. C) metabolic changes reduce the impact of starvation or gluttony. B) many adults display enduring changes in body weight. A) body weight remains relatively constant in many adults. E) all of the above

Activities such as fidgeting and maintaining posture use energy; this process is called

NEAT

According to the text, obesity is now prevalent in industrialized countries because

A) high-positive-incentive value foods are continuously and readily available in these countries. B) humans have evolved to eat as much as they can when food is available. C) cultures have evolved to promote eating when food is available. D) all of the above