weight loss and exercisejemmett/4340/4340-wtloss.pdf · weight loss caloric expenditure resting...
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Weight loss and exercise
Obesity
Obesity
Normal weight = 25 billion
Obesity
Normal weight = 25 billion
Obese = 60-80 billion
Obesity
Normal weight = 25 billion
Obese = 60-80 billion
Less severe obesity
Obesity
Normal weight = 25 billion
Obese = 60-80 billion
Less severe obesity
Fat cell hypertrophy
Obesity
Normal weight = 25 billion
Obese = 60-80 billion
Less severe obesity
Fat cell hypertrophy
Severe obesity (fat mass >30 kg)
Obesity
Normal weight = 25 billion
Obese = 60-80 billion
Less severe obesity
Fat cell hypertrophy
Severe obesity (fat mass >30 kg)
Fat cell hyperplasia)
Obesity
Normal weight = 25 billion
Obese = 60-80 billion
Less severe obesity
Fat cell hypertrophy
Severe obesity (fat mass >30 kg)
Fat cell hyperplasia)
Weight loss
Obesity
Normal weight = 25 billion
Obese = 60-80 billion
Less severe obesity
Fat cell hypertrophy
Severe obesity (fat mass >30 kg)
Fat cell hyperplasia)
Weight loss
Fat cell atrophy only
Obesity
Normal weight = 25 billion
Obese = 60-80 billion
Less severe obesity
Fat cell hypertrophy
Severe obesity (fat mass >30 kg)
Fat cell hyperplasia)
Weight loss
Fat cell atrophy only
Hyperplasia ➙more difficult weight loss/maintenance
Obesity
Obesity
Genetic factors
25% of the transmissible variance for fat mass and percent body fat
Obesity
Genetic factors
25% of the transmissible variance for fat mass and percent body fat
Cultural factors (30%)
Obesity
Genetic factors
25% of the transmissible variance for fat mass and percent body fat
Cultural factors (30%)
Individual choices (45%)
Weight Loss
Weight Loss
Caloric balance or imbalance
Energy In > Energy Out = Weight Gain
Energy In < Energy Out = Weight Loss
Weight Loss
Caloric balance or imbalance
Energy In > Energy Out = Weight Gain
Energy In < Energy Out = Weight Loss
Examples
Energy In: Big Mac 540 kcal
Energy Out: Run 40 minutes
Weight Loss
Caloric expenditure
Resting Metabolic Rate = 60-75%
Thermic effect of food = 10%
Physical activity = 15-30% of daily caloric expenditure
Example 3000 calories in one day
RMR = 1,800-2250 kcal
TEF = 300 kcal
PA = 450-900 kcal
Weight Loss
Recommendations:
1-2 lbs of weight loss per week
500-1000 fewer calories per day
or...3,500-7,000 fewer calories per week
Rapid Weight Loss
Rapid Weight Loss
Weight loss greater than 1-2 pounds per week.
Rapid Weight Loss
Weight loss greater than 1-2 pounds per week.
Where is the weight loss coming from?
Low Calorie Diets
Low Calorie Diets
Some diets reduce energy intake by 1,000-1,500 kcals/day (Very-low calorie diets < 800 kcal/day)
Low Calorie Diets
Some diets reduce energy intake by 1,000-1,500 kcals/day (Very-low calorie diets < 800 kcal/day)
temporary results at best
Low Calorie Diets
Some diets reduce energy intake by 1,000-1,500 kcals/day (Very-low calorie diets < 800 kcal/day)
temporary results at best
medical supervision
Low Calorie Diets
Some diets reduce energy intake by 1,000-1,500 kcals/day (Very-low calorie diets < 800 kcal/day)
temporary results at best
medical supervision
Muscle mass?
Low Calorie Diets
Some diets reduce energy intake by 1,000-1,500 kcals/day (Very-low calorie diets < 800 kcal/day)
temporary results at best
medical supervision
Muscle mass?
Metabolic rate?
Caloric Intake and Resting Metabolic Rate ☑
Metabolic Rate
Resting Metabolic Rate is VO2 measured at rest
ave. resting VO2 = 3.5 ml/kg/min
Estimated RMR = 1 kcal/kg/hour
For a 183 pound person, RMR = 2000 kcals.
60-75% of daily caloric expenditure
Basal metabolic rate versus Resting metabolic rate
Metabolic Rate
Metabolic Rate
Genetics
Metabolic Rate
Genetics
Gender
Metabolic Rate
Genetics
Gender
Fat-free mass
Metabolic Rate
Genetics
Gender
Fat-free mass
Dieting
Metabolic Rate
Genetics
Gender
Fat-free mass
Dieting
Hormones (e.g. Thyroid hormones, etc)
Metabolic Rate
Genetics
Gender
Fat-free mass
Dieting
Hormones (e.g. Thyroid hormones, etc)
Over eating (thermogenesis)
Metabolic Rate
Genetics
Gender
Fat-free mass
Dieting
Hormones (e.g. Thyroid hormones, etc)
Over eating (thermogenesis)
Medications/Drugs
Set Point Theory and Obesity
Set Point Theory and Obesity
Hypothalmus input
Set Point Theory and Obesity
Hypothalmus input
Physiological signals (diet composition, fat cell size, body weight, etc.)
Set Point Theory and Obesity
Hypothalmus input
Physiological signals (diet composition, fat cell size, body weight, etc.)
Cognitive signals (how do I look?, size of clothing, health concerns, etc.)
Set Point Theory and Obesity
Hypothalmus input
Physiological signals (diet composition, fat cell size, body weight, etc.)
Cognitive signals (how do I look?, size of clothing, health concerns, etc.)
Hypothalmus output
Set Point Theory and Obesity
Hypothalmus input
Physiological signals (diet composition, fat cell size, body weight, etc.)
Cognitive signals (how do I look?, size of clothing, health concerns, etc.)
Hypothalmus output
eating
Set Point Theory and Obesity
Hypothalmus input
Physiological signals (diet composition, fat cell size, body weight, etc.)
Cognitive signals (how do I look?, size of clothing, health concerns, etc.)
Hypothalmus output
eating
RMR
Set Point Theory and Obesity
Hypothalmus input
Physiological signals (diet composition, fat cell size, body weight, etc.)
Cognitive signals (how do I look?, size of clothing, health concerns, etc.)
Hypothalmus output
eating
RMR
Exercise
Diet composition on weight loss is uncertain
high protein diet may increase thermogenesis and satiety
High carbohydrates (?)
Diet Composition
Appetite
Exercise has variable affects on appetite
sedentary versus trained
exercise intensity level
Physical Activity and Body Fat
Exercise and Weight Loss ☑
Exercise and Weight Loss ☑
Exercise alone
Exercise and Weight Loss ☑
Exercise alone
less effective than diet alone
Exercise and Weight Loss ☑
Exercise alone
less effective than diet alone
Duration:
Exercise and Weight Loss ☑
Exercise alone
less effective than diet alone
Duration:
150 min/wk up to 300 min/wk
Exercise and Weight Loss ☑
Exercise alone
less effective than diet alone
Duration:
150 min/wk up to 300 min/wk
> 2000 calories/wk
Exercise and Weight Loss ☑
Exercise alone
less effective than diet alone
Duration:
150 min/wk up to 300 min/wk
> 2000 calories/wk
Caloric expenditure
Exercise and Weight Loss ☑
Exercise alone
less effective than diet alone
Duration:
150 min/wk up to 300 min/wk
> 2000 calories/wk
Caloric expenditure
0.77 kcal / kg / mile for walking
Exercise and Weight Loss ☑
Exercise alone
less effective than diet alone
Duration:
150 min/wk up to 300 min/wk
> 2000 calories/wk
Caloric expenditure
0.77 kcal / kg / mile for walking
1.53 kcal / kg/ mile for running
Exercise and Weight Loss
Exercise may be most critical to help maintain weight loss
Exercise helps to maintain muscle mass and metabolic rate
Exercise and Weight Loss
Aerobic exercise v Resistance exercise
resting metabolic rate
Aerobic Exercise: Duration versus Intensity
duration
Fat Burning Zone?
Fat Burning Zone?
Exercise and Fat Metabolism
Would you rather have 10% of person A’s money or 90% of person B’s money?
A B
Exercise and Fat Metabolism
Would you rather have 10% of person A’s money or 90% of person B’s money?
A B
Exercise and Fat Metabolism
Would you rather have 10% of person A’s money or 90% of person B’s money?
A B
Exercise and Fat Metabolism
Is low-intensity exercise best for burning fat? [A Closer Look 4.3]
40
%
fa
t
60
%
fa
t
~2
0%
fa
t
Weight Loss
Successful weight loss
diet and exercise
Diet: limited caloric intake (source of calories is unimportant)
Exercise: ~400 kcal/day or 1800-2000 kcals/week
Supplements & Weight Gain
Consumer Reports, June 2001
• Americans spent an estimated $1.4 billion on sports supplements in 1999, hoping that the pills, drinks, and powders would help them bulk up, slim down, or compete more effectively. But people who take these products are actually conducting what amounts to a vast, uncontrolled clinical experiment on themselves with untested, largely unregulated medications.
Consumer Reports, June 2001
• Americans spent an estimated $1.4 billion on sports supplements in 1999, hoping that the pills, drinks, and powders would help them bulk up, slim down, or compete more effectively. But people who take these products are actually conducting what amounts to a vast, uncontrolled clinical experiment on themselves with untested, largely unregulated medications.
• The few good scientific studies available on these "dietary" supplements suggest that they either are ineffective or, at best, produce only slight changes in performance. More disturbing, they can contain powerful and potentially harmful substances, such as:
Consumer Reports, June 2001
• Americans spent an estimated $1.4 billion on sports supplements in 1999, hoping that the pills, drinks, and powders would help them bulk up, slim down, or compete more effectively. But people who take these products are actually conducting what amounts to a vast, uncontrolled clinical experiment on themselves with untested, largely unregulated medications.
• The few good scientific studies available on these "dietary" supplements suggest that they either are ineffective or, at best, produce only slight changes in performance. More disturbing, they can contain powerful and potentially harmful substances, such as:
• Androstenedione, which can upset the body's hormonal balance when it metabolizes into testosterone and estrogen, and may cause premature puberty and stunted growth in adolescents.
Consumer Reports, June 2001
• Americans spent an estimated $1.4 billion on sports supplements in 1999, hoping that the pills, drinks, and powders would help them bulk up, slim down, or compete more effectively. But people who take these products are actually conducting what amounts to a vast, uncontrolled clinical experiment on themselves with untested, largely unregulated medications.
• The few good scientific studies available on these "dietary" supplements suggest that they either are ineffective or, at best, produce only slight changes in performance. More disturbing, they can contain powerful and potentially harmful substances, such as:
• Androstenedione, which can upset the body's hormonal balance when it metabolizes into testosterone and estrogen, and may cause premature puberty and stunted growth in adolescents.
• Creatine, a substance produced by the body that can help generate brief surges of muscle energy during certain types of athletic performance. It may also cause kidney problems in susceptible individuals.
Consumer Reports, June 2001
• Americans spent an estimated $1.4 billion on sports supplements in 1999, hoping that the pills, drinks, and powders would help them bulk up, slim down, or compete more effectively. But people who take these products are actually conducting what amounts to a vast, uncontrolled clinical experiment on themselves with untested, largely unregulated medications.
• The few good scientific studies available on these "dietary" supplements suggest that they either are ineffective or, at best, produce only slight changes in performance. More disturbing, they can contain powerful and potentially harmful substances, such as:
• Androstenedione, which can upset the body's hormonal balance when it metabolizes into testosterone and estrogen, and may cause premature puberty and stunted growth in adolescents.
• Creatine, a substance produced by the body that can help generate brief surges of muscle energy during certain types of athletic performance. It may also cause kidney problems in susceptible individuals.
• Ephedra, an herbal stimulant that acts like an amphetamine ("speed") and that some investigators hold responsible for dozens of deaths and permanent injuries.
Consumer Reports, June 2001
• Tests on products show 24.8-26% contained illegal products
• Some contain toxic levels of vitamins and minerals
• Some products contain lead, broken glass, animal feces, etc
Supplement Contamination
• Research
• For endurance, most effective in well training, caffeine naïve people (?)
• Less useful for improving strength
• Caffeine appears to enhance performance during short-term, intense cycling lasting ~5 min in the laboratory and in simulated 1500 m race time.
• Risks/Concerns
• Studies have shown that as little as one strong cup of coffee (150 to 200 milligrams of caffeine), consumed 30 to 60 minutes can affect the quality of sleep
• 400 to 500 milligrams may cause nausea, abdominal discomfort and irritability, elevated heart rate and blood pressure, and increase arrhythmias and dehydration(?)
• Withdrawal from regular caffeine ingestion also produces an array of negative side effects, including headaches, irritability and drowsiness
• USOC limit 12 ug/ml (more than 2 cups of coffee)
Caffeine
•Research
• Increase time to exhaustion or decrease sense of fatigue
• Increase speed, power, and strength
• Weight loss
•Risks/Concerns
• Injuries due to decrease awareness of fatigue and/or pain
• Acute Mild: Anxiety, insomnia, headache, restlessness, dizziness, palpitations, nausea, etc.
• Acute Severe: Arrhythmias, angina, MI, hypertension, cerebral hemorage
• Chronic: paranoid, psychosis, addiction, neuropathy, etc
Amphetamines
•Research
• The few studies that examined ephedrine as an ergogenic aid have not found significant benefits, and serious adverse events have resulted from taking ephedrine prior to strenuous exercise.
•Risks/Concerns
• Increase heat production and body temperature
• Dizziness, headache, GI distress, arrhythmias, seizures, psychosis
• Risks can be increase when combined with other substances
• Ephedrine is banned by the International Olympic Committee (IOC) and the National Collegiate Athletic Association (NCAA) and NFL.
Ephedrine
•Risks/Concerns
• New England Journal of Medicine, December 2000
•Hypertension
•Heart palpitations or heart rate increases
•Stroke
•Seizures
• Ten events resulted in death and 13 produced permanent disability.
• Less serious adverse events reported in the literature include dizziness, headache, and gastrointestinal problems.
• Also, several episodes of psychosis with ephedrine use have been reported.
• GSSI
Ephedrine Risks
• RESEARCH
• Research findings are mixed due to dosage and training differences.
• Theraputic doses: no increase in mass or strength
• Supraphysiologic doses
• Increase body mass
• Increase strength
• Increase VO2max - no
• Decrease recovery time?
• Increase aggression
• Heavy resistance training required
• Possible increase the number of receptor sites
Anabolic Androgenic Steroids
•RISKS/CONCERNS
•More risks associated with oral forms
•Men
• testicular atrophy
• decrease testosterone and sperm production
• enlargement of male breast
• prostate enlargement
•Women
• disrupts menstruration and increase masculization
• breast regression and clitoris enlargement
• deepening of voice and growth of facial hair
• Cause personality changes, liver damage, and cardiovascular disease
Anabolic Androgenic Steroids
•Steroid-like products
• Mimic testosterone functions
• Form androgen-like derivatives
•Dehydroepiandrosterone (DHEA)
•Androstenedione
•5-androstenediol
•4-androstenediol
•19-norandrostenedione
•19-norandrostenediol
Androgen Prohormones
Weight Gain
Weight Gain
• Genetics
• Body Type / Somatotype
Weight Gain
Weight Gain
•Caloric intake greater than caloric expenditure (20 calories per pound to maintain weight; 25-30 calories per pound to gain weight).
Weight Gain
•Caloric intake greater than caloric expenditure (20 calories per pound to maintain weight; 25-30 calories per pound to gain weight).
•Example for 140 and 200 pounds.
Weight Gain
•Caloric intake greater than caloric expenditure (20 calories per pound to maintain weight; 25-30 calories per pound to gain weight).
•Example for 140 and 200 pounds.
•Carbohydrates: energy for anabolism (2,000-2,800 kcals)
Weight Gain
•Caloric intake greater than caloric expenditure (20 calories per pound to maintain weight; 25-30 calories per pound to gain weight).
•Example for 140 and 200 pounds.
•Carbohydrates: energy for anabolism (2,000-2,800 kcals)
•Protein: amino acids for anabolism (360-660 kcals)
Weight Gain
•Caloric intake greater than caloric expenditure (20 calories per pound to maintain weight; 25-30 calories per pound to gain weight).
•Example for 140 and 200 pounds.
•Carbohydrates: energy for anabolism (2,000-2,800 kcals)
•Protein: amino acids for anabolism (360-660 kcals)
•Fat: can’t avoid it (340-690 kcals)
Weight Gain
•Caloric intake greater than caloric expenditure (20 calories per pound to maintain weight; 25-30 calories per pound to gain weight).
•Example for 140 and 200 pounds.
•Carbohydrates: energy for anabolism (2,000-2,800 kcals)
•Protein: amino acids for anabolism (360-660 kcals)
•Fat: can’t avoid it (340-690 kcals)
•PSM
Weight Gain
Weight Gain
• Recovery/Rest
• Eccentric muscle contractions damage muscle proteins.
• Proteins are replaced for the next 48 hours or more.
• Inadequate recovery period prevents complete muscle repair.
Weight Gain