Obesity

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Obesity
By Nelson Cheung May 25th, 2006 Biology 12
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Definition of Obesity
A thick section of adipose tissue.

• Obesity is defined as the build up of fatty
  (also called adipose) tissue.
• People become obese or overweight by consuming
  food, then not expending enough of the energy
  taken in by the food.
• The excess energy that is not expended by the
  person is stored as excess fat. In this way, body
  fat builds up.
• The built up body fat interferes with the
  functioning of several organs, which can put a
  person at increased risk for several health
  problems.

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Obesity Factors

• Genes
• Some people have a tendency, due to their genes,
  to gain weight and store fat.
• The genetic is not required for people to become
  obese, although it makes it more likely.
• Researchers are constructing a Human Obesity
  Gene Map to find the genes linked to the above
  tendencies.
• Environment
• A persons environment is also an influence in
  whether they will become obese or not.
• A healthy environment would be one that promotes
  healthy food and regular exercise.

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Measure of Obesity
- Obesity is measured through a persons Body
Mass Index (BMI).
- BMI is based on both a persons weight and
height it is a measure of the persons weight
related to their height.
- A BMI of below 18.5 indicates that the person
is underweight, a BMI of 25 indicates that the
person is overweight, and a BMI of 30 or above
indicates that the person is obese.
- Different classes of obesity exist in BMI a
person with a BMI above 25 but below 30 is
considered pre-obese, and a person with a BMI
above 35 is considered severely (morbidly) obese.
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The BMI Formula

• Developed by Belgian statistician Adolphe
  Qutelet.
• Calculates BMI by taking the persons weight and
  dividing it by their height, which is squared.
  Weight is in kilograms and height is in metres.
• BMI Weight(kilograms)/Height(metres)²
• The BMI formula has also been adapted for
  imperial units of measure (feet, inches etc.)
• BMI (703)(Weight(lbs.)/Height(inches)²)

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Other Obesity Measures

• Two other ways of measuring obesity are through
  waist circumference (abdominal obesity) and body
  fat measurement.
• In body fat measurement, the standard body fat
  for males is 15 to 18 of total body weight, and
  in females the standard body fat is 20 to 25 of
  total body weight.
• For males, obesity is defined as having more
  than 25 body fat of total body weight. In
  females, obesity is defined as having more than
  30 body fat of total body weight. (adult
  figures)
• In waist circumference measurement, the last
  healthy waist size in males is 40 inches, and
  in females it is 35 inches.
• Having a waist circumference above the above
  totals classifies a person as obese, and puts
  them at greater risk for cardiovascular disease
  and other health problems, such as type 2
  diabetes.

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Health Problems from Obesity

• Obesity is linked to higher occurrence of
  osteoarthritis (degradation of joint cartilage)
  in the hand, hip, knee, and back.
• A weight loss of ten to fifteen pounds can help
  relive symptoms and delay the progression of knee
  osteoarthritis.
• Obesity in pre-pregnant women has been shown to
  increase the frequency of neural tube defects
  (failure of neural tube to close properly)
• Folate intake, which is linked with decreasing
  the occurrence of neural tube disorders, has
  found to be less effective with higher
  pre-pregnant weights.
• Many obese people say that they have experienced
  daytime sleepiness and fatigue, both of which are
  heavily linked to accidents in transportation.

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Obesity and Cancer
Obesity has been found to have a strong
correlation with esophagus cancer, and the
chances of it rise as BMI rises. While,
premenopause, a high BMI decreases the danger of
breast cancer, there is an increased risk of
inflammatory breast cancer in overweight and
obese women. In women, endometrial (uterine)
cancer is two to four times more likely to occur
in obese women than normal women. Also, in
affluent societies, it has been estimated that
obesity accounts of 40 of uterine cancer cases.
While most studies conclude no association
between obesity and prostate cancer, it is
suggested that obese men are more likely to have
more aggressive tumours.
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Obesity and Your Heart

• Severe obesity greatly increases your chance of
  developing a cardiovascular disease. (affects
  heart and bodys circulatory system.
• Obesity greatly increases the chance that an
  individual will develop high blood pressure
  (hypertension). A theory about why the obese are
  more likely to develop hypertension is that the
  obese state of the persons body puts additional
  stress on the heart and circulatory system to
  move blood throughout the body.
• More than 75 of all hypertension cases have
  been linked directly to obesity.
• Atherosclerosis (fat deposits on artery walls
  which restrict blood flow) is much more likely to
  develop in obese people due to their increased
  fat intake and the fact that obese people are
  also more likely to develop diabetes and
  hypertension, which worsens atherosclerosis.
• Congestive heart failure (ventricle abnormality)
  and coronary artery disease (results of
  atherosclerosis) are two common cardiovascular
  diseases that have been directly attributed to
  obesity.

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Obesity and Diabetes

• Around 90 of people with Type 2 diabetes had it
  caused by being overweight or obese.
• Type 2 diabetes rates in the U.S. have tripled
  in the past thirty years.
• If you are overweight, your extra weight puts
  added stress on your body to regulate your blood
  sugar, greatly increasing your chances of
  developing diabetes
• A small weight loss, in the five to ten percent
  range can delay/prevent the development of Type 2
  diabetes in adults who are high-risk.
• In a given population, the rate of obesity is
  the greatest factor environmentally in the
  determination of the rate of diabetes.

The cost of several obesity related diseases (US)
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Obesity Trends

• According to the World Health Organization,
  there are over 300 million obese adults
  worldwide, and 1.1 billion overweight people
  worldwide.
• The condition of being overweight and being
  underweight occur today with about the same
  frequency being overweight used to be much rarer
  than being underweight.
• Several populations worldwide, including the
  Pima Indians, Australian Aborigines, and native
  Hawaiians have had increases in obesity and
  obesity-related diseases after being introduced
  to a Western diet.
• Obesity rates are highest in the poorly
  educated, although obesity rates have increased
  over all levels of education.

A chart showing obesity figures for levels of
education in 1991 and 1998.
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Obesity and Discrimination

• In a recent survey, 33 of physicians noted
  obesity as a characteristic that they felt and
  responded negatively to, behind mental illness,
  alcoholism, and drug addiction.
• 2/3 of physicians were surveyed as feeling that
  obese patients lacked the ability to control
  themselves, with 39 surveyed as feeling they
  were lazy. Surveys for nurses resulted in similar
  figures.
• In a review of employment discrimination
  studies, Prof. Mark Roehling found that
  overweight employees were assumed to be
  emotionally impaired, socially handicapped and
  as possessing negative personality traits.
• In a study performed in the 1960s, children were
  shown six pictures depicting six children a
  child with crutches, a child in a wheelchair, a
  facial disfigured child, a child with a hand
  amputated, and an overweight child. A majority of
  children viewing the pictures chose the
  overweight child as the least desirable friend.
  The study was repeated recently by researcher
  Janet Latner, among fifth and sixth grade
  children. Latner reported that the overweight
  child was chosen as the least desirable friend.