Questions and Answers
What is the definition of energy in the biological context?
The capacity to perform work.
What are the primary biological fuels used by the human body to obtain energy?
Glucose and fatty acids.
What is the term for the minimum amount of energy required by the body to function at rest?
Basal metabolism.
What is the purpose of vitamins and minerals in energy metabolism?
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How does the body release energy from biological fuels?
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What is the 'rule of thumb' method used for in estimating daily basal metabolic energy needs?
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What is the fate of energy in living systems?
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What is the role of oxygen in human energy production?
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What percentage of the energy from macronutrients is captured and stored in ATP?
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What is the primary purpose of ATP?
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What is the term for the minimal number of calories the body uses for vital physiological activities after fasting and resting for 12 hours?
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What hormone regulates metabolism?
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What is the term for the body’s rate of energy use a few hours after resting and eating?
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What is the difference between BMR and RMR?
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What is the major factor that influences the metabolic rate?
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Why do males generally have higher metabolic rates than women?
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What is the term for the energy cells use to carry out their activities?
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What is the term for all chemical changes, or reactions, that constantly occur in living cells?
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Why does a tall, slender person who weighs 150 pounds have a higher metabolic rate than a shorter person who also weighs 150 pounds?
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What happens to the basal metabolic rate as one grows older?
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Why do fat cells continue to develop throughout life?
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What is the effect of very-low-calorie diets on the metabolic rate?
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What is the formula to estimate the daily metabolic rate for men?
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Why does a heavy person expend more kilocalories when performing the same physical activity?
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What is the effect of fever on the metabolic rate?
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Why does regular exercise help maintain a higher metabolic rate?
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How does milk production in a female who has given birth affect the metabolic rate?
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Why does a person who is overfat need to reduce caloric intake to enhance the rate of weight loss?
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According to Table 10.4, approximately how many kilocalories does a 150-pound person expend while walking at 3.5 mph for 30 minutes?
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What is nonexercise activity thermogenesis (NEAT), and what are some examples of NEAT activities?
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What is the thermic effect of food (TEF), and what percentage of total caloric intake does it typically represent?
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How can an individual manipulate their energy output to increase, decrease, or maintain their weight?
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What is the recommended limit for nonwork-related screen time, including activities involving computers and video games?
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According to Table 10.4, which physical activity expends the most kilocalories per 30 minutes for a 150-pound person?
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What is the estimated daily energy expenditure in kilocalories that can be attributed to NEAT for some individuals?
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How can an individual estimate their daily energy expenditure, according to the chapter?
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What is the relationship between watching television and obesity, according to scientific studies?
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Why is it important to consider individual differences in energy expenditure when developing a weight management plan?
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Study Notes
Energy for Living
- Energy is the capacity to perform work and is essential for the body's functions.
- There are various forms of energy, including heat, mechanical, chemical, and electrical energy, which can be stored, released, moved, or transformed from one kind to another.
Energy Intake
- The body uses a mixture of biological fuels (macronutrients) and oxygen to obtain energy.
- Biological fuels are foods and beverages that contain macronutrients, such as glucose, fatty acids, and amino acids.
- Cells release energy stored in biological fuels by breaking bonds within the molecules, capturing and storing it in compounds like ATP.
Energy Output
- Energy output (energy expenditure) refers to the energy cells use to carry out their activities.
- Energy output includes:
- Basal metabolism (energy used for vital physiological activities)
- Physical activity (voluntary skeletal muscle movement)
- Nonexercise activity thermogenesis (NEAT, involuntary skeletal muscle activity)
- Thermic effect of food (energy used for digestion, absorption, and processing of macronutrients)
Basal Metabolism
- Basal metabolism is the minimal number of calories the body uses for vital physiological activities after fasting and resting for 12 hours.
- Basal metabolic rate (BMR) is influenced by:
- Thyroid hormone
- Body composition (lean body mass)
- Sex
- Body surface area
- Age
- BMR declines with age, primarily due to the loss of fat-free tissues like muscle.
Factors that Influence Metabolic Rate
- Factors that increase metabolic rate:
- Fever
- Stimulant drugs (e.g., caffeine)
- Pregnancy
- Milk production in lactating females
- Recovery after exercise
- Emotional stress
- Factors that decrease metabolic rate:
- Hypothyroidism (underactive thyroid gland)
- Low calorie intake
Calculating Metabolic Energy Needs
- The "rule of thumb" formula for estimating daily metabolic rate:
- For men: 1.0 kcal/kg/hr
- For women: 0.9 kcal/kg/hr
- Estimate daily basal metabolic rate by multiplying the hourly value by 24.
Physical Activity
- Physical activity increases energy expenditure above basal energy needs.
- Energy expenditure during physical activity depends on:
- Type and intensity of activity
- Duration of activity
- Weight of the person
- A heavier person expends more kilocalories when performing the same activity.
Nonexercise Activity Thermogenesis (NEAT)
- NEAT refers to involuntary skeletal muscle activity, such as shivering, fidgeting, and maintaining muscle tone.
- NEAT can account for up to 700 kcal daily in some individuals.
Thermic Effect of Food (TEF)
- TEF is the energy used for digestion, absorption, and processing of macronutrients.
- TEF accounts for 5-10% of total caloric intake.
Putting It All Together
- To estimate daily energy expenditure, add kilocalories burned for basal metabolism, physical activity, and TEF.
- Use formulas published by the Food and Nutrition Board of the Institute of Medicine to estimate daily energy expenditure.
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Description
Test your knowledge on energy metabolism, basal metabolic rate, and factors that influence it. Learn how vitamins and minerals regulate energy levels.