Ch 5: Energy Balance and Metabolism Flashcards
Chemical Processes within a living organism that provide energy
Metabolism
Storage form of Glucose
Glycogen
What is a chemical compound that provides energy to to drive muscle contraction, transmission of nerve impulses and chemical reactions that facilitate life
Adenosine Triphosphate (ATP) - The energy currency of life
ATP consists of:
Adenosine molecule bonded to 3 Phosphate Groups
Estimated calorie needs per day, by age, sex, and physical activity level.
Total Daily Energy Expenditure (TDEE)
Total number of calories required
Age, sex, and physical activity level, thermic effect of feeding (TEF), resting metabolic rate (RMR), and non-exercise activity thermogenesis (NEAT)
Relationship between Heat and Energy (Mechanical, Electrical or Chemical) and how these are converted into one another
Thermodynamics
First Law of Thermodynamics
Law of Conservation of Energy
Energy can be transferred from one form to another
Energy for Survival
Basal Metabolic Functions
Calories burned during the digestion and processing of food
TEF
Non-Exercise Activity Thermogenesis
NEAT
Calories burned during exercise and physical activity
TEA
Energy Out
Resting Metabolic Rate (RMR)
Thermic Effect of Feeding (TEF)
Thermic Effect of Activity (TEA)
Non-Exercising Activity Thermogenesis (NEAT)
Total number of calories burned when the body is completely at rest
Resting Metabolic Rate (RMR) also known as Basal Metabolism
What does Resting Metabolic Rate (RMR) support?
Breathing, Circulating Blood, Organ Functions and Basic Neurologic functions
Low Metabolic Rate
Low Thyroid Hormone production, High percentage of Body Fat and Low level of Lean Body Mass, Age
High Metabolic Rate
High Thyroid Hormone production, High level of Lean Body Mass (Muscle)
Percentage of calories burned during Thermogenic Effect of Food (TEF)
10% Consuming, Digesting and Utilising Food (protein is the most)
Accounts for the most variability of Energy Expenditure
Thermic Effect of Activity (TEA) 15 - 30% of energy burned
All Energy expended that is not sleep, eating or exercising
Non-Exercise Activity Thermogenesis (NEAT)
One Metabolic Equivalent (MET)
One MET is often used to describe RMR and energy expenditure. One Metabolic Equivalent (MET) = 3.5 ml O2 / Kg/min. METs can be used to prescribe exercise training intensities
Light Intensity Activities
Less than 3 METS
Sleeping, watching TV, light walking
Moderate Activities
MET 3 - 6
Bicycling, Moderate walking, Calisthenics
Vigorous Activities
Over 6 METS
Jogging, Pushups, pullups, Running in place, Jump rope
Metabolic rate when sleeping
Reduced by 15%
Short Sleep Patterns
Increased Obesity Risk
Hormonal response, Appetite, Food Choices and RMR
Effects of Sleep Deprivation
An increase in insulin resistance at a cellular-signalling level and increased glucose, insulin and cortisol.
Sleep-deprived individuals consume more calories from fatty foods versus protein.
Sleep-deprived people may also experience a decrease in plasma leptin and an increase in ghrelin, which increase hunger and appetite.
Even a single night of total sleep deprivation can influence energy expenditure and metabolism.
Hormone that increases appetite
Ghrelin
Hormone that decreases appetite
Leptin
Hormones that affect Energy Out
Thyroid Hormone, Cortisol and Testosterone
The biological process of combining free fatty acids with Glycerol to form Triglycerides
Lipogenesis
Biological process of breaking down stored triglycerides into free fatty acids and Glycerol
Lipolysis
Process of breaking down the glycogen molecule into its individual glucose units for entry into the energy pathways
Glycogenolysis
A metabolic pathway that results in the generation of glucose from non-carbohydrate carbon substrates such as Lactate, Glycerol and Glucogenic Amino Acids
Gluconeogenesis
Thyroid Hormone stimulation of Metabolism
Increased Oxygen consumption and rates of ATP breakdown. When Thyroid Hormones are elevated, fat loss is enhanced
Hyperthyroidism Effects
Increased resting energy expenditure
Weight Loss
Reduced Cholesterol Levels
Increased Lipolysis and Gluconeogenesis
Cortisol
Stress Hormone released by Adrenal Glands
Glucocorticoid
Rapidly Increases Blood Glucose Levels
Works against Insulin, keeps blood glucose elevated by Gluconeogenesis
Effect of Testosterone
- Testosterone is a hormone that plays a key role in carbohydrate, fat and protein metabolism. It has a major influence on body-fat composition and muscle mass in men.
- Testosterone helps control pathways involved in glycolysis, glycogen synthesis and lipid and cholesterol metabolism
Testosterone Deficiency
Increased fat mass (central adiposity in particular), reduced insulin sensitivity and impaired glucose tolerance, which may be related to diabetes and risk for heart disease
Factors involved in Energy In
Appetite
Environmental factors
Psychological factors
Individual Variation
Food Processing
Factors involved in Appetite
Food in Stomach
Leptin and Ghrelin production
Social Factors
Activity Level
Hormones in the control of appetite
Leptin, CCK, Ghrelin and PPY
Hormone produced by adipose cells that decreases appetite when released. Leptin sends a signal to the brain signaling that enough food has been consumed and appetite should be inhibited. Leptin is supposed to tell the brain that we have reached a state of desired caloric intake and how many calories are stored
Leptin
Low Leptin Levels
Induce Appetite, suppresses energy expenditure, thyroid and reproductive hormones and Immunity
Leptin Resistance may play a role in Obesity
Hormone produced by the stomach with small amounts produced by Small Intestine, Pancreas and Brain
Ghrelin (hunger hormone)
Effects of Ghrelin
- Stimulates Appetite, Increases Food Intake. promotes fat storage
- Stimulates fat deposition and Growth Hormone Release
Hormone released in the gastrointestinal system (Cells of the Upper Small Intestine) and is responsible for stimulating the digestion of fat and protein. Stimulates the Gallbladder to contract (bile)
Cholecystokinin (CCK)
- Neuropeptide hormone linked to the autonomic nervous system. Neuropeptides are small protein-like molecules used by neurons to communicate with each other
- Helps stimulate the sympathetic nervous system, which stimulates appetite and fat storage (Beck, 2006).
NPY (Neuropeptide Y)
Environmental Factors Influencing Energy Intake
- Access/Availability to Food and Drinks
- Desirability to Food and Drinks
- Prices
- Shopping Atmosphere
- Marketing
- Demand Side Effects
- Individual Preferences to Food and Drink
Mindful Eating
- Eat when Hungry
- Do not allow Emotions to Control Eating
- Engage all 6 Senses
- Modest Portions
- Savor Small Bites
- Eat Slow
- Chew thoroughly
- Do not skip meals
Individual Factors that Affect Metabolism
- Body Composition (Lean body weight)
- Very Low Calorie Diets
- Age
- Brown Fat (Genetics)
- Food Allergies
- Lifestyle Habits
- Caffeine
- Thyroid Function
- Food Processing (Thermogenesis)
Digesting, absorbing, transporting and storing the food you consume which takes calories
Thermogenesis
Any procedure that alters food from its natural state.
Food Processing
Types of Food Processing
Freezing, Drying, Milling, Canning, Mixing or adding Sugar, Fat, Salt or Additives
Types of Energy Usage
Biosynthesis
Detoxification
Thermogenesis
Ion Transport
Muscle Contraction
Three Primary Energy Systems
ATP-PC Phosphagen System (15 seconds)
Glycolysis (60 seconds)
Oxidative (180 seconds)
Human storage of ATP
80-100 grams (a few seconds of high-intensity activity)
ATP-PC System
adenosine triphosphate-phosphocreatine
Uses the energy released from the breakdown of phosphocreatine (also called creatine phosphate) Anaerobic
It is the primary energy system used for all-out exercise.
- Limited amount stored in skeletal muscle
- Creatine kinase is the enzyme that breaks down phosphocreatine (PC) into creatine and an inorganic phosphate (Pi).
ATP-PC System
Replenishment of PC Stores
After 2 Minutes of Rest
Provides energy for medium to high-intensity bursts of activity that last from 10 seconds to 2 minutes
Anaerobic (glycolytic) system
The breakdown (-lysis) of glucose through a series of enzymatic reactions. Glycolysis uses glucose in the blood or glycogen to form ATP rapidly without oxygen. If glucose is used, two ATPs are generated. If glycogen is used, three ATPs are formed.
Glycolysis
Product of Glucose breakdown during Glycolysis (Anaerobic)
Lactate
Pathway of Anaerobic Glycolysis (2-3 min of exercise)
Glucose -> Anaerobic Glycolysis -> Pyruvate ->Lactate
Lactic Acid (lactate + Hydrogen Ion)
Pathway of Aerobic Glycolysis
Glucose->Pyruvate->Krebs Cycle->Electron Transport Chain - 36 ATP
Ratio between the amount of carbon dioxide (CO2) produced in metabolism and oxygen (O2) used.
Respiratory Exchange Ratio (RER)
commonly measured during a VO2 max test
Respiratory Exchange Ratio (RER) at rest
0.8
RER that indicates that mix of fat and carbohydrates is the predominant fuel source
RER of 0.85
RER that indicates that fat is the predominant fuel source
RER of 0.70
RER that indicates that carbohydrates are the predominant fuel source
RER of 1.00 or more
Breaking down fat for energy; does not directly
Fat Oxidation (Beta Oxidation)
Lipolysis (Free Fatty Acids and Glycerol) transported to the mitochondria as acetyl-CoA