weight loss and exercisejemmett/4340/4340-wtloss.pdf · weight loss caloric expenditure resting...

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