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Fat oxidation is highly responsive to dietary fat intake, particularly when changes occur abruptly.
Fat oxidation is highly responsive to dietary fat intake, particularly when changes occur abruptly.
False
What happens to excess protein in the body?
What happens to excess protein in the body?
What is the primary reason that high-protein diets can contribute to weight gain?
What is the primary reason that high-protein diets can contribute to weight gain?
High protein intake can lead to fat storage because excess protein is converted to fatty acids.
The body's primary mechanism for handling abundant carbohydrate is to store it as ______.
The body's primary mechanism for handling abundant carbohydrate is to store it as ______.
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Which of the following statements is TRUE regarding glucose oxidation?
Which of the following statements is TRUE regarding glucose oxidation?
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Excess dietary carbohydrate is primarily converted to fat.
Excess dietary carbohydrate is primarily converted to fat.
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What effect does excess dietary carbohydrate have on fat oxidation?
What effect does excess dietary carbohydrate have on fat oxidation?
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Which of the following is the most efficient way for the body to store excess energy?
Which of the following is the most efficient way for the body to store excess energy?
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Match the following macronutrients with how their excess is handled by the body:
Match the following macronutrients with how their excess is handled by the body:
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Which nutrient is converted to body fat most efficiently?
Which nutrient is converted to body fat most efficiently?
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The body prioritizes converting excess carbohydrates into fat over converting excess proteins.
The body prioritizes converting excess carbohydrates into fat over converting excess proteins.
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What percentage of ingested energy intake is used to convert dietary fat to body fat?
What percentage of ingested energy intake is used to convert dietary fat to body fat?
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To convert dietary triglycerides into body fat, the body first removes __________ fatty acids.
To convert dietary triglycerides into body fat, the body first removes __________ fatty acids.
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What must happen to carbohydrates before they can be stored as body fat?
What must happen to carbohydrates before they can be stored as body fat?
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Using excess dietary protein to create fat is a high priority for the body.
Using excess dietary protein to create fat is a high priority for the body.
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In excess, how does protein oxidation change during energy metabolism?
In excess, how does protein oxidation change during energy metabolism?
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Match the energy-yielding nutrients with their conversion efficiency to body fat:
Match the energy-yielding nutrients with their conversion efficiency to body fat:
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What happens to acetoacetate in the presence of two hydrogens?
What happens to acetoacetate in the presence of two hydrogens?
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Mental alertness is typically diminished during prolonged fasting.
Mental alertness is typically diminished during prolonged fasting.
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List two physiological symptoms of starvation.
List two physiological symptoms of starvation.
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The body relies on ______ to fuel the brain during fasting.
The body relies on ______ to fuel the brain during fasting.
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Match the following metabolic adaptations with their descriptions:
Match the following metabolic adaptations with their descriptions:
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Which of the following statements is true regarding the adaptations to fasting?
Which of the following statements is true regarding the adaptations to fasting?
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Depression is a psychological effect of food deprivation.
Depression is a psychological effect of food deprivation.
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How does a low-carbohydrate diet force the body into ketosis?
How does a low-carbohydrate diet force the body into ketosis?
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What percentage of glucose is primarily consumed by the brain and nerve cells?
What percentage of glucose is primarily consumed by the brain and nerve cells?
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The body can use protein as the main energy source during fasting.
The body can use protein as the main energy source during fasting.
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What is produced in the liver to serve as an alternative energy source for the brain during fasting?
What is produced in the liver to serve as an alternative energy source for the brain during fasting?
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During the first few days of fasting, body protein provides about ___ percent of the needed glucose.
During the first few days of fasting, body protein provides about ___ percent of the needed glucose.
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What triggers ketosis during fasting?
What triggers ketosis during fasting?
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Red blood cells can rely on fatty acids for energy.
Red blood cells can rely on fatty acids for energy.
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What substance is released in urine when there is a high concentration of ketone bodies in the blood?
What substance is released in urine when there is a high concentration of ketone bodies in the blood?
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A fruity odor on the breath, known as ___ breath, is indicative of ketone production.
A fruity odor on the breath, known as ___ breath, is indicative of ketone production.
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How much of the body's energy output is spent by the brain at rest?
How much of the body's energy output is spent by the brain at rest?
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Match the following components to their corresponding functions during fasting:
Match the following components to their corresponding functions during fasting:
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The metabolism slows during fasting to conserve body tissues.
The metabolism slows during fasting to conserve body tissues.
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What happens to appetite as ketosis develops during fasting?
What happens to appetite as ketosis develops during fasting?
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When nutrient availability is low, the body relies on its ___ and ___ stores for energy.
When nutrient availability is low, the body relies on its ___ and ___ stores for energy.
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Which form of fuel does the brain primarily prefer for energy?
Which form of fuel does the brain primarily prefer for energy?
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Fasting can lead to a dramatic loss in both fat and lean tissue.
Fasting can lead to a dramatic loss in both fat and lean tissue.
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Study Notes
Excess Nutrient Consumption and Metabolism
- Excess calorie intake, regardless of nutrient source (protein, carbohydrate, or fat), promotes fat formation. Fat storage is the most direct and efficient process.
- Converting dietary fat to body fat uses only 5% of ingested energy, while converting dietary carbohydrate requires 25%.
- Protein and carbohydrate are less prioritized for fat conversion; protein first replaces daily losses, and carbohydrate fills glycogen stores.
- Any excess energy from any nutrient can still be converted to fat.
Nutrient Contribution to Fuel Mix
- Dietary protein and carbohydrate influence the fuel mix during energy metabolism.
- Protein's contribution is usually minor and constant, but increases with excessive intake.
- Carbohydrate oxidation significantly increases with excess intake.
- Fat oxidation is not responsive to dietary fat intake, especially with abrupt changes. Excess fat accumulates.
Excess Protein
- The body cannot store excess amino acids as such; it converts them to other compounds..
- Muscle growth is a response to stimulus like hormones or physical activity, not just overeating protein.
- Overeating protein leads to increased protein oxidation, displacing fat in the fuel mix.
- Excess protein is deaminated and the remaining carbons used to make fatty acids and stored as triglycerides.
Excess Carbohydrate
- The body first stores excess carbohydrate as glycogen, but glycogen storage is limited.
- Glucose oxidation adapts rapidly to carbohydrate intake.
- Excess glucose can be converted to fat, but it's a minor pathway and occurs only after glycogen stores are filled.
- Excess carbohydrate can displace fat in the fuel mix, potentially contributing to weight gain.
Excess Fat
- Excess dietary fat is efficiently stored as body fat.
- Almost all excess dietary fat is stored.
- Weight gain results from exceeding energy needs, regardless of the nutrient source, but fat is stored most efficiently when the excess comes from dietary fat.
Feasting and Fasting
- During feasting (overeating), the body stores glycogen and fat.
- During fasting, the body draws on glycogen and fat stores for energy.
- Liver glycogen is depleted after about 24 hours, leading to glucose deficiency.
- Fat breakdown increases significantly during periods of fasting.
- Muscle protein is broken down to supply amino acids for gluconeogenesis when glycogen stores are depleted.
Ketosis
- Ketosis occurs during prolonged fasting.
- The body produces ketone bodies from fatty acids for alternative energy, particularly for the brain.
- Ketones provide energy for some brain cells, reducing reliance on protein.
- Ketosis is characterized by ketone bodies in the blood (ketonemia) and urine (ketonuria) and a fruity breath odor.
- Ketosis suppresses appetite.
Starvation
- Fasting adaptations help conserve body tissues.
- Metabolic rate and cellular work decrease during fasting and starvation.
- Starvation leads to a loss of lean tissue and can cause significant physical and psychological symptoms, including organ failure.
- The body can adapt to fasting for up to about two months.
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Description
Explore the effects of excess nutrient consumption on metabolism, focusing on how different nutrients contribute to fat formation and energy fuel mix. Understand the processes by which the body converts excess calories into fat and the prioritization of nutrients during metabolism.
