Obesity, Diabetes, and Physical Activity

1
Chapter 22

• Obesity, Diabetes, and Physical Activity

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Chapter 22 Overview

• Obesity
• Terminology
• Prevalence
• Control of body weight
• Etiology
• Health problems
• Treatment
• Physical activity

• Diabetes
• Terminology
• Prevalence
• Etiology
• Health problems
• Treatment
• Physical activity

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ObesityTerminology and Classification

• Overweight
• Body weight exceeds standard weight for given
  height and frame size
• Not precise terminology
• Does not account for body composition
• Obesity
• Excessive body fat (men gt25, women gt35)
• Borderline obese men 20 to 25, women 30 to 35

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ObesityTerminology and Classification

• Body mass index (BMI)
• Body weight in kilograms/(height in m)2
• Most widely used standard for obesity
  classification
• Does not account for body composition
• Overweight 25.0 to 29.9 kg/m2
• Obese 30.0 kg/m2
• BMI classification cut points change for
  difference races and ethnicities

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Table 22.2
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ObesityPrevalence in the United States

• Prevalence ? dramatically since 1980
• Prevalence of overweight has not changed much
• Obesity continues to increase
• More prevalent in some races and ethnicities
• Mexican-American men
• Black women
• Increasing prevalence in children and teens

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Figure 22.1a
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Figure 22.1b
9
Figure 22.1c
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Figure 22.2
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Figure 22.3
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ObesityPrevalence in the United States

• With age fat mass ?, lean body mass ?
• Over age 25, average person gains 0.7 to 1 lb
  per year
• Up to 33 extra lb by age 55
• Will have significant effect on health care
• Earlier onset of obesity
• Increasing rates of obesity
• Earlier onset of obesity-related diseases

13
Obesity Worldwide Prevalence

• Increases in obesity not unique to United States
• Canada, Australia, Europe have seen increases to
  a lesser degree
• Available data vary
• Most recent studies show obesity spreading to all
  regions of the world

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Table 22.3
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ObesityControl of Body Weight

• Body usually carefully balances kilocalorie
  intake and expenditure
• Gain of 1 lb/year represents imbalance of 3,111
  kcal per year
• Body can balance to within 9 kcal per day
• Body may regulate around set point using
• Resting metabolic rate (RMR)
• Thermal effect of meals (TEM)
• Thermal effect of activity (TEA)

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ObesityControl of Body Weight

• RMR
• Bodys metabolic rate in the early morning
• 60 to 75 of total energy expenditure
• TEM
• Energy expended to digest, store nutrients, etc.
• 10 of total energy expenditure
• May be defective in obese individuals

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ObesityControl of Body Weight

• TEA
• Energy expended to accomplish activities
• 15 to 30 of total energy expenditure
• Balance of RMR, TEM, TEA
• Helps body adapt to ? or ? kilocalorie intake
• Controlled by sympathetic nervous system
• Key for maintaining weight around set point

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Figure 22.4
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ObesityControl of Body Weight

• Set point regulation versus weight gain
• Diet composition alters set point
• Physical activity alters set point
• High-fat diets usually ? overfeeding
• Other factors
• Larger portions/restaurant supersizing
• Higher fat consumption
• More eating away from home

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ObesityEtiology

• Physiological factors
• Heredity/genetics
• Hormonal imbalances
• Altered basic homeostatic mechanisms
• Lifestyle factors
• Cultural habits
• Inadequate physical activity
• Improper diets

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Figure 22.5
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ObesityHealth Problems

• Morbidity presence or rate of disease
• Mortality death from disease
• Obesity and overweight ? ? mortality
• Major increased risk BMI gt35

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Figure 22.6
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ObesityHealth Problems

• Obesity and overweight associated with
• Cardiovascular disease
• Type 2 diabetes
• Cancer (endometrial, breast, colon)
• Liver, gallbladder disease
• Osteoarthritis
• Sleep apnea
• Metabolic syndrome rate parallels obesity

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Obesity Genetic Versus Lifestyle Effects

• Pima Indians study in genetics versus lifestyle
• Native lifestyle ? lean and healthy
• Western diet/lifestyle ? high rates of obesity
• Men 64
• Women 75
• Obesity often accompanied by diabetes
• Men 34
• Women 41

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Obesity Genetic Versus Lifestyle Effects
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ObesityHealth Problems

• Changes in normal body function
• Vary with individual
• Vary with degree of obesity
• Lethargy
• Polycythemia
• Low blood O2/high blood CO2
• Clotting, heart failure

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ObesityHealth Problems

• Body fat distribution disease risk factor
• Upper-body (android) obesity (men)
• Lower-body (gynoid) obesity (women)
• Waisthip girth ratio and visceral fat index
  identify fat distribution
• Android obesity ? higher risk for
• Cardiovascular disease
• Elevated blood lipids
• Diabetes

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Figure 22.7
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Figure 22.8a
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Figure 22.8b-c
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ObesityHealth Problems

• Exacerbates existing diseases
• Weight loss reduces severity of
• Angina pectoris
• Hypertension
• Congestive heart disease
• Heart attack recurrence
• Varicose veins
• Diabetes
• Orthopedic problems

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ObesityHealth Problems

• Emotional and psychological factors
• Can help cause obesity
• Can be exacerbated by obesity
• Obesity social stigma
• Media glamorize thin people
• But norms may shift as obesity becomes more common

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ObesityGeneral Treatment

• Weight loss kilocalorie intake lt kilocalorie
  expenditure
• Oversimplification
• Weight loss treatment multifactorial
• Loss not to exceed 1 to 2 lb per week
• Weight loss a long-term project
• Maintain balanced diet with caloric deficit
• Reduce intake of fat and simple sugars

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ObesityGeneral Treatment

• Hormone treatments
• Decrease appetite
• Increase RMR
• Serious side effects, life threatening
• Surgical treatments
• Intestinal bypass
• Gastric banding or bypass
• Reserved for most extreme, serious cases

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ObesityGeneral Treatment

• Behavior modification change in eating patterns
  or habits. Examples
• Can only eat in one location
• No snacking
• No second helpings
• Appealing, simple weight loss approach

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Obesity Role of Physical Activity in Weight
Control

• Overeating and inactivity major causes of
  obesity
• Kilocalorie restriction and exercise best
  treatments
• Exercise alters body composition
• Significant long-term kilocalorie deficit
• Significant long-term fat loss
• EPOC ? ? postexercise metabolism

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Obesity Role of Physical Activity in Weight
Control

• Body mass and composition changes with exercise
• ? Total weight
• ? Fat mass, percent body fat
• Maintained or ? FFM
• Changes long term (6-12 months)

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Table 22.4
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Obesity Role of Physical Activity in Weight
Control

• Both aerobic and resistance training ? weight
  loss
• Exercise important aspect of weight loss
• Must combine exercise kilocalorie restriction
• Decrease rate of visceral fat accumulation
• Energy balance equation
• Kilocalorie intake kilocalories excreted (RMR
  TEM TEA)
• Helps clarify weight loss mechanisms

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Obesity Role of Physical Activity in Weight
Control

• Exercise effects on appetite
• Leads to appetite suppression in male animals
• Leads to no change or ? intake in female animals
• Less activity ? less food intake
• Causes for appetite suppression
• Higher circulating catecholamines
• Higher body temperature

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Obesity Role of Physical Activity in Weight
Control

• Exercise effects on RMR
• May increase with training
• Resistance training of interest (RMR related to
  FFM)
• Exercise effects on TEM
• Pre- and postmeal exercise ? ? TEM
• Chronic exercise training ? inconclusive
• Exercise effects on fat mobilization
• During exercise, FFA mobilization ?
• Possible causes hGH, sympathetic stimulation,
  catecholamines

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Obesity Role of Physical Activity in Weight
Control

• Spot reduction a myth
• Local exercise ? local fat loss
• Exercise draws on all fat stores
• Local exercise ? local muscle development
• Spot reduction studies
• Tennis dominant versus nondominant arms
• Intense sit-up training program

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Obesity Role of Physical Activity in Weight
Control

• Low-intensity aerobics and weight loss
• High intensity ? ? percent energy from CHO
  oxidation
• Low intensity ? ? percent energy from fat
  oxidation
• Low intensity ? no change in total fat
  kilocalories expended
• Low intensity ? ? in total kilocalories expended
• Fatmax zone
• Zone where fat oxidation rates near peak
• 55 to 72 VO2max

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Table 22.5
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Figure 22.9
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Obesity Role of Physical Activity in Weight
Control

• Exercise gimmicks ineffective. Examples
• Mark II Bust Developer
• Astro-Trimmer Exercise Belt
• Slim-Skins Vacuum Pants
• Reality exercise and weight loss require work

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Obesity Physical Activity and Health Risk
Reduction

• Exercise ? ? risk of disease mortality
• Irrespective of weight loss
• Good news for those who struggle with weight loss
• Active lifestyle and fitness more important

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DiabetesTerminology and Classification

• Diabetes mellitus
• Hyperglycemia
• Insulin insufficiency and/or resistance
• Type 1
• Type 2
• Gestational
• Prediabetes

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DiabetesTerminology and Classification

• Type 1 diabetes
• Autoimmune (b-cells destroyed, no insulin)
• Insulin-dependent diabetes mellitus (IDDM)
• 5 to 10 of all diabetes cases
• Type 2 diabetes
• Loss of insulin sensitivity (insulin resistance)
• Non-insulin-dependent diabetes mellitus (NIDDM)
• 90 to 95 of all diabetes cases
• Term adult onset no longer correct

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DiabetesTerminology and Classification

• Gestational diabetes
• Develops in pregnant women
• 4 of pregnancies, causes complications
• Prediabetes
• Predictor of full-blown diabetes
• Impaired fasting glucose or glucose tolerance
• Glucose tolerance test diagnostic test
• Oral
• Intravenous

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DiabetesTerminology and Classification

• Signs of type 1 diabetes
• Excessive urination, thirst
• Weight loss, extreme hunger
• Fatigue, irritability
• Signs of type 2 diabetes
• Any type 1 symptom
• Persistent infections, sores
• Vision changes
• Tingling, numbness in limbs

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DiabetesPrevalence

• 17 million people diagnosed
• 7 million people undiagnosed
• 57 million people prediabetic
• 50 increase from 1990 to 2005
• Prevalence (diagnosed) varies by group Black
  11.8, Hispanic 10.4, Asian American 7.5, White
  6.6

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DiabetesEtiology

• Type 1 diabetes
• Pancreatic b-cells destroyed
• Cause may be autoimmune, viral infection,
  degeneration
• Sudden onset in childhood, young adulthood
• Type 2 diabetes
• Gradual onset (children and adults)
• Impaired insulin secretion, action,
  responsiveness
• Obesity major factor
• b-cells, target cells less responsive

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DiabetesHealth Problems

• Cardiovascular disease (all forms)
• Kidney disease
• Neural disease
• Eye disorders (blindness)
• Dental disease
• Amputations

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DiabetesGeneral Treatment

• Type 1 diabetes
• Insulin administration
• Diet
• Exercise
• Type 2 diabetes
• Weight loss
• Diet
• Exercise
• Recently developed drugs

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Type 1 DiabetesRole of Physical Activity

• Exercise complicates glycemic control
• Hypoglycemia a risk
• Can lead to unacceptable plasma glucose
  fluctuations
• Requires careful monitoring
• Monitor foot sensation, healing
• Helps reduce risk of coronary, cerebral, and
  peripheral arterial diseases

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Type 2 DiabetesRole of Physical Activity

• Exercise enhances insulin sensitivity
• Muscle contraction mimics insulin action
• Lowers blood glucose
• Decreases insulin requirement
• Short-term (72 h) effect
• Combination of resistance and aerobic training
  may be optimal