Obesity

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Obesity Body Composition
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Obesity

• Multi-million dollar industry
• Listed as a major risk factor by AHA in 1998
• Without obesity...
• 25 less CHD
• 2 years to average life expectancy

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Obesity

• What diseases are associated with obesity?
• Heart disease
• Hypertension
• Diabetes
• Renal disease
• Pulmonary disease
• Osteoarthritis
• Cancers

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Obesity

• 58 million
• Creeping obesity
• lower metabolic rate
• sedentary lifestyle
• Over-eating
• Not a requirement of aging
• A long-term process
• Is not solely related to overeating

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Obesity

• How does it develop?
• Obesity cycle

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Obesity

• Genetics
• Number of calories consumed
• Dietary recall
• Isotope studies
• Types of foods eaten
• Fat is more easily stored than carbohydrates or
  proteins
• High fat and high glycemic index foods
• Daily activity
• Which comes first inactivity or obesity?
• Increases resting metabolic rate (due to increase
  in fat free mass)
• Increases caloric expenditure(during exercise

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Obesity - Genetics

• 25-40 of the cause of obesity
• Internal fat more so than subcutaneous fat
• Ob gene
• Creates leptin (Greek for thin) that is
  responsible for satiety
• Leptin inhibits neuropeptide Y (NPY) which
  stimulates food intake

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Obesity - Genetics

• Genes may decrease number of leptin receptors in
  hypothalmus
• Differences in resting metabolic rate
• Predisposition of sweet, high-fat food
• Impaired hormonal functions
• Insulin, cortisol, hGH
• Greater number of fat cells

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Obesity Calories Consumed

• 3500 calories equal a pound of fat
• Over eating can make is easier for the body to
  store fat and harder for it to remove fat

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Insulin
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Fat Transport
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Lipoprotein Lipase

• Adipose (Capillary) LPL
• Breaks down Chylomicrons, VLDL and LDL
• Their triglycerides are stored in fat cells
• Muscle LPL (or type L-Hormone sensitive lipase)
• Breaks down fats for metabolism inside muscle
  cells

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Syndrome X

• Consider a person who over eats (high fat, high
  sugar) and is inactivity
• What affect would this lifestyle have on insulin?
• 1. Insulin resistance and Hyperglycemia
• How would this affect body composition?
• Obesity

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Syndrome X

• Insulin resistance and Hyperglycemia
• Decrease in muscle LPL (type L-HSL)
• Decrease in fat metabolism
• Increase in adipose LPL in adipose cells
• Increase in fat storage

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Syndrome X

• Other conditions of syndrome.
• 1. Insulin resistance and Hyperglycemia
• 2. Hypertension
• 3. Hyperlipidemia

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Syndrome X

• Hypertension
• Hyperinsulinemia
• Sodium retention
• Increased arterial resistance
• Increase adipose tissue with relatively fewer
  capillaries

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Syndrome X

• Hyperlipidemia (high blood fats)
• With obesity...
• High cholesterol (25)
• High triglycerides (75)
• Low HDL
• Decease LPL in liver
• Less TG removal
• Increase LDL production
• Increase HDL removal

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Syndrome X

• How does exercise help?
• Exercise increases GLUT-4 (reduces insulin
  resistance)
• Increase oxidative enzymes (increase fat
  metabolism)
• Increase muscle blood flow
• Reduces abdominal fat

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Obesity Type of Food

• Glycemic Index
• Less sugars and straches
• More fruits, vegetables, and whole grains
• Thermic effect of foodHighest for protein,
  carbohydrates and then fats
• Fats can only be stored as fat
• Carbohydrates and proteins have other options

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Obesity - Environment
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Obesity - Inactivity
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Obesity

• Energy Imbalance

INTAKE Big Mac 590 calories
EXPENDITURE Running ? miles 590 calories
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Energy Balance

• Energy (food) intake
• Energy expenditure

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Energy Balance

• Unbalance...
• Eat less
• More active
• Both
• Diet
• 3 of calories to store fat
• 25 of calories to store carbohydrate
• Exercise

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Total Energy Expenditure

• Resting Metabolic Rate
• Thermogenesis
• Thermic effect of food
• Thermogenic substances (catecholamines, drugs,
  etc)
• Facultative Thermogenesis (cold exposure)
• Psychological stress
• Physical Activity

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Energy - Resting Metabolic Rate

• Approximately 1 kcal/kg/hr

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Energy - Resting Metabolic Rate

• 70 of total energy expenditure (TEE)
• 10 difference among people
• RMR influenced by body size, age, sex, and
  Fat-free mass (FFM)

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ACSM
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Energy - Resting Metabolic Rate

• RMR influenced by body size, age, sex, and
  Fat-free mass (FFM)
• RMR 370 (21.6 x fat-free mass in kg)

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Energy - Thermic effect of food

• 5-10 of TEE
• Highest for protein, carbohydrates and then fats
• Less for obese
• Higher if exercise before (or after) eating

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Energy - Facultative Thermogenesis

• Shivering
• Increase metabolic rate up to 5 times
• Brown adipose tissue (BAT)
• Higher metabolic rate than white fat

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Energy - Food Intake

• Hypothalmus
• Hunger center
• Satiety center
• Gluostatic theory
• Lipostatic theory
• Leptin
• Released from adipose cells
• Decreases appetite
• Obese may have defective leptin receptors in brain

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Energy - Food Intake

• Aminostatic theory
• Thermostatic theory
• Heat from digestion
• Other factors
• GI stretch receptors
• Nutrient level
• Hormone levels
• Psychological factors

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Energy Set Point Theory

• Hypothalmus controls body weight similar to how a
  thermostat controls temperature
• Increase body fat releases leptin
• Leptin inhibits neuropeptide Y (NPY) which
  stimulates food intake
• Fat levels decrease to normal or previous levels
• Decrease body fat inhibits leptin release
• NPY increase and stimulate hunger
• Fat levels increase to normal or previous levels

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Energy Expenditure
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Energy Expenditure
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Energy Weight Gain
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Energy Weight Gain

• Obesity Larger cells or more cells?
• Obese individuals have 3x more and 40 larger
  adipose cells
• Weight loss mainly through decrease size
• However, fat cells can be added or deleted in
  adulthood

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Energy Weight Gain

• Hypertrophy
• Hyperplasia
• Average person 25-30 billion
• Obese person 260 billion
• Number of cells increase up to age 10
• Further weight gain due to hypertrophy
• Hyperplasia occurs with extreme weight gain

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Energy Weight Gain

• Nutrition
• Rats and litter size
• Activity
• Active at young age
• The key is early prevention

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Energy Healthy Weight Gain

• Increase caloric intake by 200 to 1000 kcals per
  day
• Increase healthy carbohydrates
• If needed, increase protein intake but no more
  than 2.0 g/kg of body weight
• Proper training with adequate rest

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Weight Loss
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Weight Loss - Dehydration

• Sweating
• Lose up to 1.5 to 4.0 liters per hour
• Low carbohydrate diet
• 1 gram of glycogen is stored with 3 grams of
  water
• Deamination of protein results in water loss

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Weight Loss - Medical Procedures

• Starvation diets
• Surgery
• Bypass
• Liposuction
• Drugs
• Appetite-suppressing drugs
• Thermogenic drugs (RMR)
• Fat blocking drugs

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Weight Loss - Dieting

• Water loss due to glycogen depletion
• 1/3 to 2/3 weight loss regained within 5 years
• Setpoint Theory metabolic rate
• Weight cycling and Lipoprotein Lipase (LPL)

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Weight Loss - Caloric Restriction

• Most common method
• Carbohydrate restriction
• Dehydration
• Loss of LBM
• Limits exercise
• Weight loss in independent of dietary composition
  (i.e. the type of food)

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Weight Loss - Semi-starvation Diets

• Theory less caloric intake, suppress appetite,
  change eating behavior,
• Concerns requires medical supervision.

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Weight Loss - Ketogenic Diet

• Ketones are a by product of lipid metabolism
• Ketones can serve as fuel to CNS
• Theory is they suppress appetite
• Excess ketones (a form of energy) is lost in
  urine rather than stored in the body

OAA
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Weight Loss - Ketogenic Diets

• High uric acid levels
• Electrolyte loss
• Arrhythmias
• Acidoisis
• Kidney damage
• Fatigue

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Weight Loss Low Carbohydrate Diets

• Theory suppress appetite, elevated thermic
  effect of digestion, better insulin control
• Concerns kidney and liver damage, dehydration,
  electrolytes, loss of lean tissues, adequate
  vitamins and minerals, low energy level

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Bowman SA  Spence JT Am Coll Nutr (Journal of
the American College of Nutrition.) 2002 Jun
21(3) 268-74

• OBJECTIVES To evaluate free-living adults' diets
  that ranged from very low to high amounts of
  carbohydrate for their energy content,
  nutritional quality and correlation to Body Mass
  Index.
• METHODS Adults ages 19 years and older, who had
  complete dietary intake data on day-1 of the
  USDA's 1994 to 1996 Continuing Survey of Food
  Intakes by Individuals (CSFII 1994-1996), were
  divided into four groups--very low, low, moderate
  and high carbohydrate--based on the percent total
  energy from carbohydrate. Mean energy, nutrient,
  food intakes and Body Mass Index values were
  compared among the groups. SUDAAN software
  package was used for the data analysis and
  pair-wise mean comparisons (p
• RESULTS The high-carbohydrate diet was lower in
  energy and energy density (number of kilocalories
  per gram of total amount of food consumed) than
  the other three diets. Macronutrient composition
  varied significantly among all the four groups.
  Nutrient density (amount of nutrient per 1,000
  kilocalories of energy consumed) of vitamin A,
  carotene, vitamin C, folate, calcium, magnesium
  and iron increased and that of vitamin B12 and
  zinc decreased with an increase in the percent
  total energy from carbohydrate. The
  high-carbohydrate group ate more of low-fat
  foods, grain products and fruits. This group also
  had the lowest sodium intake. Adults eating a
  high-carbohydrate diet are more likely to have
  Body Mass Index values below 25.
• CONCLUSION A study of diets of free-living
  adults in the U.S. showed that diets high in
  carbohydrate were both energy restrictive and
  nutritious and may be adopted for successful
  weight management.