Understanding Nutrition

1
Understanding Nutrition

• Chapter 9
• Weight Control
• Overweight and Underweight
• By
• A. Fellah, Ph.D.

2
A Fat Cell

• Excess energy is stored in the fat cells of
  adipose tissue. The amount of fat reflects both
  the number and the size of fat cells

3
An Adipose Cell
An adipose, or fat, cell seems to expand almost
indefinitely. The more fat it stores, the larger
it grows.

• accommodate its swollen contents.

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Fat Cell Metabolism

• Lipoprotein lipase (LPL) promotes fat storage in
  both adipose and muscle cells.
• LPL is mounted on fat cell membranes.
• Obese people have many fat cells, they have more
  LPL activities in their fat cells than lean
  people do.
• LPL activities is partially regulated by
  gender-specific hormones-estrogen and
  testosterone.
• Lower body is less active than the upper body in
  releasing fat.
• Easily regain lost weight LPL activity increases
  after weight lose (the fatter the fastest).

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Fat Cell Development
Fat cells are capable of increasing their size by
20-fold and their number by several thousandfold.
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Causes of Obesity

• Set Point The point at which controls are set.
  The set-point theory that relates to body weight
  proposes that the body tends to maintain a
  certain weight by means of its own internal
  controls.
• 1. Genetics
• Identical twins are 2x as likely to weigh the
  same as fraternal twins.
• Genes may not cause obesity, but genetic factors
  may influence the food intake and activity
  patterns and the metabolic pathways.
• Liptin a protein produced by fat cells under
  direction of the ob gene that decreases appetite
  and increases energy expenditure.
• ob is the obesity gene that expressed in the fat
  cells which codes for liptin.
• It acts as a hormone, in the hypothalamus.
• Mice with a defective ob gene dont produce
  leptin and can weigh up to 3x as normal mice and
  have 5x as much body fat.

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A Model of Leptins effects on Energy Balance and
Body Fatness
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Leptins Action in the Body
Leptin maintains energy homeostasis. When the
body gains fat, the increase in leptin shifts
energy balance toward the negative eat less and
spend more energy. Such a scenario would ensure
that all fat gains were followed by losses, but
this is not the case in reality, of course.

• When leptin levels are high, the hypothalamus
  produces melanocortins, dampen appetite

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Leptins Action in the Body
When the body loses fat, the decrease in leptin
shifts energy balance toward the positive eat
more and spend less energy.
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• Most obese people have high levels of leptin, but
  their energy balance does not automatically shift
  to the negative, suggesting a resistance to
  leptins action in obesity.
• When leptin is low, hypothalamus produces
  neuropeptide Y, which stimulates appetite and
  slows energy expenditure (Leptin inhibits
  neuropeptide Y production)
• When leptin level is high, the hypothalamus
  produces melanocortins, which dampen appetite and
  increases energy expenditure.

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Both mice are genetically Obese, they lack the
gene for Leptin
Receives Leptin
No Leptin
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Mice with and Without Leptin Compared
Both of these mice have a defective ob gene.
Consequently, they do not produce leptin. They
both became obese, but the one on the right
received daily injections of leptin, which
suppressed food intake and increased energy
expenditure, resulting in weight loss.
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Causes of Obesity, cont.

• 2. Environment
• Overeating
• Overweight people overeat, whether this is true
  has been difficult to determine.
• Genetically obese rats eat much more than their
  nonobese littermate at early age.
• Overeating contributes to obesity, but does not
  fully explain it.
• Toxic food environment a term coined to refer to
  the easy access to and overabundance of high-fat,
  high kcalories food in our society.

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• Physical Inactivity
• Modern technology has replaced physical activity
  at home and at work.
• Remote control, escalators, automobiles, buttons,
  ..
• Inactivity contributes to weight gain and poor
  health.
• Watching TV may contribute most to physical
  inactivity.
• People may be obese, not because they eat too
  much, but because they move too little.

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Pear Shaped Body
Basic body shapes. The pear normally has narrow
shoulders, a small chest, and an average-size
waist. Fat is concentrated in the hips and
thighs. Weight loss in these areas is usually
difficult.
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Pear Shaped Body

• The apple looks round in the middle.
• Fat is concentrated in the waist and can be lost
  with diet and exercise.
• Apple-shaped people are at increased risk for
  diabetes, hypertension, high blood cholesterol,
  and heart disease.

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Waist to hip ratio
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Body Fat Location Is Important to Health Apple
The man on the left is 6 feet tall and weighs 240
pounds the man on the right is 6 feet 1 inch
tall and weighs 230 pounds. Although similar in
weight and height, the man on the left is at
higher risk for diabetes, hypertension, and heart
disease due to his apple shape and body fat
content.
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Controversies in Obesity Treatment

• Elusive Goals
• Every overweight person can achieve slenderness
  and should pursue it.
• Only 5 of all people who successfully lose
  weight maintain their losses for at least a year.

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• Dangers of Weight Loss
• Fad Diets often sound good, but fall short to
  delivering on their promises.
• Adverse reactions from headache to death.
• Weight Cycling repeated cycles of weight loss
  and gain, yo-yo effect.
• Increase the risks of chronic disease and
  premature death.
• Psychological Problems
• Most weight-loss programs assume that the problem
  can be solved simply by applying willpower and
  hard work.
• Ineffective treatment and its associated sense of
  failure add to a persons psychological burden.

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The Weight Cycling Effect of Repeated Dieting
Each round of dieting is followed by a rebound of
weight to a higher level than before.
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Obesity in Adults
Prevalence of overweight among adults in the
United States
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Gradual Weight Loss Increases Success
People who lose weight gradually are more likely
to keep it off than those who lose weight
rapidly. The weight loss graphed here averages a
quarter pound per week.
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The Psychology of Weight Cycling

• Shows how the devastating psychological effects
  of obesity and dieting perpetuate themselves.

25
Aggressive Treatments of Obesity

• 1. Drugs
• An effective drug that can used over time without
  adverse side effects currently doesnt exists.
• Sibutramine suppresses appetite by inhibiting
  the uptake of serotonin in the brain, suppressing
  appetite.
• Effective when used with a reduced-kcalorie diet
  and physical activity.
• Dry mouth, headache, constipation, insomnia, and
  high blood pressure.
• Orlistat Inhibits pancreatic lipase activity,
  thus block fat digestion and absorption by 30.
• Effective with a reduced-kcalorie diet, low fat
  diet.
• Gas, frequent bowel movement and reduced
  absorption of fat soluble vitamins.

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Diet Aids

• Herbal Products
• St. Johns wort contains substance that enhance
  serotonin which suppress appetite.

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Weight Loss Drugs
There is no lack of weight-loss books and
products. There is a lack of approaches that help
people keep weight off.
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Weight-Loss Products
A few examples of bogus weight-loss products that
were removed from the market.
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Weight-Loss Products Herbal
A few examples of bogus weight-loss products that
were removed from the market.
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2. Surgical Procedures Used in Treatment of
Obesity
The dark pink areas highlight the flow of food
through the GI tract. Notice that the procedure
maintains a relatively normal flow. The pale
pink areas indicate the sections that have been
bypassed.
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Surgical Procedures Used in Treatment of Obesity
The dark pink areas highlight the flow of food
through the GI tract. Notice that the flow
bypasses most of the stomach, all of the
duodenum, and some of the jejunum. The pale
pink areas indicate the sections that have been
bypassed.
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Gastric Bypass Surgery
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Weight Goals and Expectations Compared
Reasonable weight goals and expectations
compared.
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Reasonable Treatments of Obesity

• Eating Plans
• Be involved in planning.
• Energy out should exceed energy in by about
  500 kcal/day.
• Make nutritional adequacy a high priority.
• Emphasize nutrient-dense foods.
• Eat small portions. Share a restaurant meal with
  a friend or take home half for lunch tomorrow.
• Limit low-fat treats to the serving size on the
  label.
• Make legumes, whole grains, vegetables, and
  fruits central to your diet plan.
• Eat slowly.
• Limit high-fat foods.
• Limit concentrated sweets and alcoholic
  beverages.
• Drink a glass of water before you begin to eat
  and another while you eat. Drink plenty of water
  throughout the day (8 glasses or more a day).

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Reasonable Treatments of Obesity, cont.

• Physical Activity
• Activity and Energy Expenditure.
• Activity and Basal Metabolism.
• Activity and Appetite Control.
• Activity and Psychological Benefits.
• Choosing Activities.
• Spot Reducing.

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Physical Activity Guidelines
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Peoples bodies are shaped by the activities they
perform.
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Reasonable Treatments of Obesity, cont.

• Behavior and Attitude
• Behavior modification the changing of behavior
  by the manipulation of antecedents (cues or
  environmental factors that trigger behavior), the
  behavior itself, and consequences (the penalties
  or rewards attached to behavior).
• Behaviors change tip
• Keep a record of diet and exercise habits it
  reveals problem areas.
• Strategies Dont grocery shop when hungry.
• Eat slowly.
• Exercise when watching TV.
• Learn alternative way to deal with emotions and
  stress.
• Attend support groups regularly or develop
  supportive relationships with others.
• Adopt permanent lifestyle changes to achieve and
  maintain a health weight.

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Reasonable Treatments of Obesity, cont.

• To prevent excessive weight gain
• Eat regular meal and limit snacking.
• Drink water instead of high-kcalorie beverages.
• Select low-fat foods regularly and limit dietary
  fat to 30 of daily kcalorie intake.
• Become physically active and limit TV viewing
  time.
• Underweight
• It is a body weight so low as to have adverse
  health effects it is generally defined as BMI
  lt18.5.
• It is a far less prevalent problem than
  overweight, affecting 5 of US adults.
• Thin people may find gaining wt difficult.
• In wt gain or wt loss, physical activity and
  energy intake are essential components to a sound
  plan.

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Maintainers Versus Weight Regainers
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Maintainers Versus Weight Regainers
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Weight-Gain Strategies

• Eat energy-Dense Foods.
• Eat at least 3 meals a day.
• Eat large potions of food and expect to feel
  full.
• Eat snacks between meals.
• Drink plenty of juice and milk.
• Exercise and eat to build muscles.

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The Female Athlete Triad
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Eating Disorder Terms

• Anorexia Nervosa
• Binge-eating disorder
• Bulimia Nervosa
• Cathartic
• Cognitive therapy
• Eating disorder
• Emetic
• Female athlete triad

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Eating Disorders in Women
Eating disorders occur in males as well as
females, but females make up approximately 95 of
all cases.
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Anorexia Nervosa
A days diet? For a person with anorexia nervosa,
it was. The foods shown provide approximately 562
calories.
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Essential Features Helping to Diagnose
Criteria used for the diagnosis of anorexia
nervosa.
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Women with anorexia nervosa see themselves as fat
even when they are dangerously thin.
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Essential Features Helping to Diagnose, con.
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(No Transcript)
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Diagnosis Bulimia Nervosa
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Eating Disorders
The vicious cycle of restrictive dieting and
binge eating.
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Binge Eating Disorder
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Binge Eating
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Binge - Purge Disorder
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The Clash Between Culture and Biology
The trend toward size acceptance. Acceptance of a
realistic standard of body weight and shapeone
that corresponds to health and physical
fitnessand respect for people of all body sizes
may be the most effective measures that can be
taken to prevent anorexia nervosa and bulimia
nervosa.
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Summary

• Various theories are used to explain obesity.
• Fat cell development, fat cell metabolism, and
  set-point theory are theoretical explanations.
• Genetics and environmental factors have been
  proposed as causes of obesity.
• Differences of opinion lead to controversies in
  weight loss treatment.
• Choices for treatment of obesity are many.
• Aggressive treatments include drugs and surgery.

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Summary

• Weight regains are common.
• Reasonable treatments for obesity involve
  planning well-balanced eating plans with physical
  activity.
• Behavior and attitude are important aspects.
• Weight maintenance programs are valuable after
  weight goals are met.
• Underweight conditioned pose health problems
  also.
• Strategies for weight gain include intake of
  energy-dense foods, regular meals, large
  portions, extra snacks and exercise to build
  muscles.

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Summary

• Anorexia nervosa, bulimia nervosa and binge
  eating are eating disorders characterized by
  sociological, neurochemical and psychological
  problems.
• The nutritional component of treatment involves
  dietary intervention and education.