Chapter Twenty-four THE CARBOHYDRATE HYPOTHESIS, III HUNGER AND SATIETY Flashcards
What is the primary way to lose weight according to the text?
To grow accustomed to feeling hungry.
Who described a ‘rational basis’ for the dietary treatment of childhood obesity in 1975?
James Sidbury, Jr.
What type of diet did James Sidbury propose for treating childhood obesity?
A diet very low in both carbohydrates and calories.
What key observation did Sidbury make about fasted children?
Fasted children ‘rarely, if ever, complained of hunger.’
What hormone is mentioned as being chronically elevated in obese patients?
Insulin.
What type of foods did the obese children in Sidbury’s practice typically consume?
Foods dominated by carbohydrates such as crackers, potato chips, French fries, cookies, and soft drinks.
What did Sidbury believe a low carbohydrate diet would do regarding insulin?
Decrease the constant stimulation of insulin-secreting cells.
What percentage of carbohydrates did Sidbury’s diet contain?
15 percent carbohydrates.
What is the relationship between hunger and satiety discussed in the text?
Hunger and satiety are central to discussions of obesity and caloric balance.
True or False: The ability to remain on a calorie-restricted diet is solely a matter of willpower.
True.
What two hypotheses were proposed in the 1970s to explain the brain’s regulation of hunger and satiety?
- Glucostat hypothesis * Lipostatic regulation.
What does the glucostat hypothesis explain?
The short-term initiation of meals based on glucose levels.
What is the lipostatic regulation hypothesis?
It posits that the body defends a certain set point of body weight or adiposity.
What is a major criticism of the set point or lipostat concept?
It lacks precedent in physiology and does not explain how the brain monitors fat stores.
According to physiological psychologists, what is a primary mechanism through which we maintain homeostasis?
Behavior.
What did Curt Richter conclude about the effort to maintain a constant internal environment?
It constitutes one of the most universal and powerful behavior urges.
What did Richter and Adolph conclude about eating behavior in their experiments with rats?
Eating behavior is fundamentally driven by calories and energy requirements.
Fill in the blank: According to Adolph, food acceptance and the urge to eat are found to have relatively little to do with _______.
a local condition of the gastro-intestinal canal.
What did the experiments with rats regarding salt and calcium reveal about hunger?
Rats will develop a ‘taste’ for essential nutrients when deprived.
What is the relationship between hunger, satiety, and insulin mentioned in the text?
Insulin may act as both a fattening hormone and a hunger hormone.
What phenomenon did Sidbury note regarding insulin levels during fasting?
Insulin levels rapidly decrease during fasting.
What is the significance of the ‘set point’ concept in the context of obesity?
It suggests that individuals defend a predetermined level of body fat.
What has been a consequence of the specialization in obesity research disciplines?
Little awareness of each other’s work and results among researchers.
What is the main observation about food acceptance and hunger in rats according to Adolph?
Food acceptance and the urge to eat in rats are primarily driven by quantitative deficiencies of currently metabolized materials.
Who was Jacques Le Magnen and what was notable about his contributions to the study of hunger?
Jacques Le Magnen was a blind French physiological psychologist known for his encyclopedic memory and significant research on hunger and weight regulation.
What device did Le Magnen design in the early 1950s?
A device to monitor food intake in rats over twenty-four-hour cycles.
What was one of Le Magnen’s key findings regarding meal sizes and hunger in rats?
The size of the meal determines how long rats will go before they get hungry again.
What concept did Le Magnen’s research confirm about eating behavior in animals?
Eating behavior is driven by quantitative deficiencies of currently metabolized materials.
What is the difference between hyperphagia and hypophagia in rats?
Hyperphagia is when rats eat to excess while awake, and hypophagia is when they are in negative energy balance during sleep.
How do rats utilize fatty acids during sleep according to Le Magnen’s findings?
Rats mobilize fatty acids from adipose tissue for fuel while sleeping, reducing the need for external calorie intake.
What happens to rats’ eating behavior when insulin suppresses fatty acid mobilization?
Rats eat immediately when insulin suppresses fatty acid mobilization.
What are the consequences of lipogenesis on hunger according to Le Magnen?
Lipogenesis promotes hunger by removing available fuel from circulation.
What is the diurnal cycle of hunger and satiety regulated by?
Insulin secretion and its responsiveness to glucose.
What is a primary function of the hypothalamus in regulating hunger?
The hypothalamus integrates sensory signals and adjusts the filling and emptying of fuel reserves.
According to Friedman and Stricker, what must the supply of fuel to body tissues remain?
Adequate for them to function during all physiological conditions.
Fill in the blank: The body has no way of distinguishing between fuels from _______ sources and fuels from _______ sources.
[internal] and [external]
How does the body maintain caloric homeostasis?
By ensuring a continuous flow of energy to cells rather than focusing on body fat stores.
What is the implication of Le Magnen’s hypothesis regarding weight gain?
Weight gain is promoted by factors that deposit fatty acids in fat tissue and inhibit their mobilization.
What role does insulin play in fat storage and hunger regulation?
Insulin elevates fat storage and inhibits the mobilization of fatty acids, leading to increased hunger.
True or False: According to the hypothesis, hunger and satiety are manifestations of metabolic needs.
True
What was found regarding the relationship between nutrition and fertility in reproductive biology research?
The availability of metabolic fuels, not just body fat, is critical for fertility.
What is considered the most important environmental factor in fertility and reproduction according to some biologists?
The immediate availability of metabolic fuels
This perspective contrasts with the common belief that body fat is the critical variable.
What did George Wade and Jill Schneider observe in their research on hamsters regarding estrous cycles?
Hamsters will go into heat regardless of being fat or lean, as long as they can eat as much food as they want.
What happens to estrous cycles in hamsters when both fatty-acid and glucose oxidation are inhibited?
Their estrous cycles stop, and they remain infertile regardless of weight changes.
What hormone’s secretion is shut down in monkeys if they go twenty-four hours without food?
The hormone that triggers ovulation.
What effect does insulin have on reproductive cycles in animals?
Infusing insulin will shut down reproductive cycles unless food intake is increased.
What hypothesis explains the infertility associated with obesity in humans and lab animals?
The metabolic-fuel hypothesis of fertility.
What type of diet may benefit women struggling with infertility or amenorrhea according to the metabolic-fuel hypothesis?
A low-carbohydrate, high-fat diet.
What is suggested to be a primary cause of obesity according to the hormonal environment hypothesis?
Increased insulin secretion or increased sensitivity to insulin.
What is required to successfully lose body fat according to the hormonal environment hypothesis?
Create a hormonal environment in which fatty acids are mobilized and oxidized more than stored.
What is the consequence of a drug suppressing appetite in terms of energy expenditure?
The body will perceive caloric deprivation and reduce energy expenditure.
What happens to fat cells after a person quits smoking according to the text?
Fat cells increase lipoprotein-lipase activity, leading to weight gain.
What did Judith Rodin’s research reveal about weight gain in ex-smokers?
Ex-smokers consume no more calories than those who do not gain weight after quitting.
What physiological mechanism does nicotine influence to induce weight loss?
Increases insulin resistance and decreases lipoprotein-lipase activity on fat cells.
What does the alternative hypothesis of obesity suggest about weight and appetite regulation?
They are induced by changes in the regulation of fat metabolism and insulin secretion.
How do seasonal variations in insulin levels correlate with weight in humans?
Insulin is highest in late fall and early winter, and lowest in late spring and early summer.
What radical implication does the physiological hypothesis have regarding anorexia nervosa?
It may be caused by a physiological defect of fat metabolism and insulin.
What is the palatability hypothesis regarding diet and obesity?
The more palatable the food, the more likely individuals are to overindulge.
What did Le Magnen’s research suggest about taste perception in animals?
Taste perception changes based on caloric depletion and nutritional requirements.
How does the perception of taste change after food consumption according to the text?
It becomes more favorable for foods that meet caloric and nutritional needs quickly.
What role does insulin play in determining the palatability of food?
Insulin is secreted in waves that correlate with the intake of palatable food.
What is the first wave of insulin secretion triggered by?
The consumption of palatable food, before glucose enters the bloodstream.
What is the first wave of insulin secretion?
The first wave begins within seconds of eating palatable food and lasts for about twenty minutes.
What is the function of the first insulin wave?
To prime the body for incoming glucose.
How long does it take for insulin to have a measurable effect on blood-glucose levels?
It takes almost ten minutes.
What does the first insulin wave do to the mobilization of fat?
Shuts down the mobilization of fat from adipose tissue.
What does Le Magnen suggest about the relationship between the first insulin wave and hunger?
It increases the metabolic background of hunger.
What does the phrase ‘L’appétit vient en mangeant’ mean?
The appetite comes while eating.
What are cephalic reflexes?
Physiological reactions induced by the smell, sight, or thought of food.
Which animals have been studied for cephalic-phase insulin secretion?
Humans, rats, monkeys, cats, sheep, and rabbits.
What did Nicolaidis demonstrate about the taste of sweetness?
Rats will secrete insulin in response to the mere taste of a sweet substance.
What is the term for the anticipatory secretion of insulin?
Pre-adaptive.
What does chronic hyperinsulinemia lead to between meals?
It leads to cravings for carbohydrates.
What did Terry Powley suggest about lesions in the hypothalamus?
They may cause hypersecretion of insulin and amplify hunger perception.
What is the relationship between insulin and hunger according to Judith Rodin?
Insulin is a major candidate for a physiological mechanism responsive to environmental stimuli.
What happens to insulin levels after consuming carbohydrates?
Insulin levels rise, leading to the deposition of fats and carbohydrates in adipose tissue.
What is the effect of high insulin levels on the liver?
It prevents the liver from releasing glucose stored as glycogen.
What is the craving for carbohydrates likened to?
An addiction.
What does Robert Kemp suggest about sugar’s effect on the brain?
Sugar induces an exaggerated response in the reward center of the brain.
What can happen when the nucleus accumbens is excessively activated?
It can lead to abuse and addiction.
How does avoiding carbohydrates affect insulin levels?
It lowers insulin levels, ameliorating hyperinsulinemia.
What is transient hypercholesterolemia?
A temporary elevation of cholesterol due to fat loss.
What must be established about carbohydrates to make informed dietary decisions?
Whether carbohydrates are the cause of obesity and overweight.
What is necessary for permanent dietary change according to Kemp?
Confidence in health benefits from altering eating habits.
True or False: The craving for carbohydrates is a natural physiological condition.
False.
Fill in the blank: The chronic hyperinsulinemia of the obese may lead to increased _______.
Consumption.
What is the effect of a low-carbohydrate diet on children’s growth?
Children experienced continued normal linear growth despite being very low in calories.
This challenges the belief that low-calorie diets harm growth.
What are the glands associated with the thyroid gland?
Four glands that lie either behind or embedded in the thyroid gland.
These glands are part of the endocrine system.
What do Adolph’s studies suggest about weight gain and energy-dense foods?
They contradict the notion that weight gain is solely from energy-dense foods.
They suggest that humans may not gain weight simply by consuming such foods.
What eating strategy does Barbara Rolls advocate for weight management?
Learning to feel full on fewer calories by consuming soups and fiber-rich foods.
This approach involves diluting calories with water or fiber.
What is the nocturnal behavior of rats?
Rats are nocturnal.
This means they are active during the night and rest during the day.
Why do diabetologists typically miss the first wave of insulin secretion?
They measure insulin at longer intervals, missing details of what happens in between.
This leads to overlooking the immediate insulin response after a meal.
What does ‘of or about the head’ refer to in the context of reflexes?
It refers to reflexes that are not mediated by peripheral organs but are stimulated by nerve signals from the brain.
This highlights the central role of the brain in these reflex actions.
What is the calorie count reported by the USDA’s standard nutrient database?
Eleven hundred calories.
This figure can vary; the Center for Science in the Public Interest reports sixteen hundred calories.
