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Weight management

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Greatest in people who were the heaviest before weight loss. LPL works to restore set point... 33. Weight loss and health status ... – PowerPoint PPT presentation

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Title: Weight management


1
Weight management
  • Overweight
  • Obesity
  • Underweight

2
Overweight and obesity
  • 66 of of adults in US have BMI 25 or greater
  • 33 children 2-19 in US are overweight or at risk
  • So prevalent is considered an epidemic
  • 300 million adults worldwide in both developed
    and developing countries

3
Fat cell development
  • Fat cells increase rapidly in late childhood and
    early puberty
  • Fat cells may continue to increase in number
    after body growth stops if there is an excess of
    calories
  • Overweight people have more fat cells and the
    cells contain more fat that a lean persons

4
Fat cell loss
  • Does not occur
  • When weight loss occurs, fat cells shrink, but do
    not go away
  • Makes it easier to regain weight

5
Lipoprotein lipase (LPL)
  • Enzyme that promotes fat storage in fat cells and
    muscle
  • Obese people have more activity in fat cells than
    lean people (same in muscle)
  • Fat storage in obese people is more efficient and
    moderate increases in energy intake result in a
    more fat storage than a lean person

6
Acitivity of LPL
  • Gender specific
  • Partially regulated by estrogen and testosterone
  • In women LPL is more active in breasts, hips and
    thighs
  • In men LPL is more active in abdomen
  • …

7
  • Release of lower body fat is less active in women
  • Release of abdominal fat is less active in men
  • Women have a harder time loosing weight,
    especially around hips and thighs

8
LPL activity after weight loss
  • Weight loss signals fat cells to produce more LPL
  • Greatest in people who were the heaviest before
    weight loss
  • LPL works to restore set point…

9
Set point theory
  • Body adjusts metabolism to restore original
    weight
  • Energy expenditure increases after weight gain
    and decreases after weight loss
  • Energy expenditures differ from what is expected
    from body composition alone
  • Explains why it is difficult for an overweight
    person to maintain weight loss and for an
    underweight person to maintain weight gain

10
Causes of overweight and obesity
  • Genetics
  • Environment

11
Genetics
  • True causative role is rare
  • Prader-willi syndrome excessive appetite, short
    stature, massive obesity, mental retardation
  • Does affect susceptibility to overweight and
    obesity
  • Activity of leptin and grhelin is genetically
    regulated…

12
Leptin
  • Obesity gene (ob) codes for leptin in adipose
    (fat) tissue and stomach cells
  • Leptin is a hormone that affects the hypothalamus
    of the brain

13
Leptin from fat cells
  • Signals hypothalamus that fat stores are
    sufficient
  • Signals long term satiety
  • Promotes negative energy balance
  • Suppresses appetite
  • Increases metabolism

14
Leptin from stomach cells
  • Released in presence of food
  • Signals short term satiety

15
Defective ob gene
  • In mice reduced amount of leptin and consequent
    weight gain
  • Rare leptin deficiencies in human
  • Leptin injections decrease appetite and stimulate
    weight loss

16
Normal ob gene
  • Most obese people produce sufficient, or high,
    leptin
  • Weight gain seems to increase concentrations
  • Obese people may be resistant or insensitive to
    leptin
  • Not a useful treatment for common overweight and
    obesity

17
Leptin and energy intake decrease
  • May be a starvation hormone
  • Levels decline when energy intake is low
  • Metabolism slows

18
Other functions of leptin
  • Must be present for female fertility
  • Stimulates growth of new blood vessels
  • Promotes formation of red blood cells
  • Supports immune system
  • Elevated levels seen in obese children may
    promote early puberty

19
Ghrelin
  • Secreted by stomach
  • Interacts with leptin
  • Influences hypothalamus
  • Promotes positive energy balance
  • Stimulates appetite
  • Promotes fat storage

20
Ghrelin levels
  • Blood levels rise and fall before and after
    eating
  • Fasting levels correlate inversely with body
    weight
  • High in lean
  • Exceptionally high in anorexics
  • Indication that both body weight and nutritional
    status influence amounts
  • Remain high after eating in Prader -Villi
    syndrome
  • Remain higher than normal in obese people who
    binge eat

21
Role of ghrelin during famine
  • Maximizes fat storage
  • Fights to maintain body weight

22
Factors affecting ghrelin levels
  • Declines after gastric bypass surgery
  • Declines in positive energy balanceweight gain
  • Decline on proportion to PPY (polypeptide Y)…

23
PPY
  • Secreted by GI tract cells in proportion to kcals
    consumed
  • Signals satiety and decreases food intake
  • May become a useful treatment in overweight and
    obesity

24
Other functions of ghrelin
  • Growth
  • Sleep
  • Lack of sleep increases ghrelin and decreases
    leptin

25
Uncouples reactions
  • Energy is lost as heat
  • Energy is not trapped in ATP
  • Occurs in brown fat
  • Important in infants and hibernating animals
  • Occurs in white fat and other tissues
  • Resists weight gain
  • Increases BMR
  • Genetic variations occur
  • May account, in part, for ease or resistance to
    weight gain

26
Opposing hormones
  • Satieting hormones
  • Leptin
  • PPY
  • CCK
  • Appetite stimulating hormone
  • Ghrelin

27
Ideal diet
  • Stimulates satiety hormones and suppresses
    ghrelin
  • Low fat, high fiber diets are the best at
    achieving this goal

28
Environment vs. genetics
  • Both appear to play a role in body weight
  • Interactions between the two occur
  • Genetic factors involved in behaviors

29
Current trends
  • Average weight has increased over the past three
    decades
  • Genetics has not changed
  • Recent weight gain trends appear to be
    environmentally caused

30
Overeating
  • Encouraged by environment that constantly exposes
    us to high calorie, high fat foods that readily
    accessible
  • Portion sizes of ready made food are often huge

31
Physical activity
  • Current environment encourages inactivity
    through sedentary life styles
  • Physical activity has been decreased through
    reliance on technology
  • Home
  • Work
  • Transportation

32
Weight loss
  • 35-45 women and 20-30 of men in U.S. are
    trying to loose weight

33
Weight loss and health status
  • If overweight person is in good health, potential
    for harming health if weight loss is achieved
    through poor nutritional methods
  • If overweight person is in bad health with two or
    more risk factors for chronic illness, weight
    loss through a nutritionally sound plan is
    advised
  • If overweight person has a life threatening
    condition, weight loss through sensible means is
    indicated

34
Social issues
  • Stereotyping overweight people
  • Psychological problems resulting from hostility
    and contempt of others

35
Dangerous interventions
  • Yo-yo dieting
  • Fad diets
  • Check out the end of the chapter for pros and
    cons
  • Some weight loss products (non prescription)
  • Ephedrine, which is no longer in use
  • Laxatives found in dieters teas senna,
    cascara, aloe castor oil, etc.
  • Gimmicks
  • Cellulite same as any other fat

36
Aggressive treatments drugs
  • Prescription drugs
  • Sibutramine
  • Appetite suppressant
  • Many side effects rise in blood pressure, rapid
    heart rate, dry mouth , headache
  • Not indicated if patient has high blood pressure
  • Orlistat
  • Inhibits pancreatic lipase
  • Blocks dietary fat by 30
  • Side effects include gas, frequent bowel
    movement, reduced absorption of fat soluble
    vitamins
  • OTC low dose version approved Alli

37
Aggressive treatment surgeries
  • Gastric bypass
  • Gastric band

38
Weight loss stategies
  • Limit discretionary calories
  • Limit fat
  • Eat healthy fats
  • Increase fiber
  • Drink adequate water
  • Eat lower energy dense foods
  • Eat smaller portions
  • Eat balanced diet
  • Increase activity
  • Continue behavior changes to maintain weight loss

39
Underweight
  • Genetic and environmental causes

40
Weight gain strategies
  • Increase caloric intake with energy dense foods
  • Eat regular meals
  • Large portions
  • Extra snacks
  • Drink extra juice and milk
  • Strength training to add muscle, which weighs
    more than fat/equal volume

41
The end
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