The Obesity module is available here.Presentation Transcript
Obesity Welcome to the obesity module. The rapid rise in the prevalence of obesity in both rich and poor countries in recent years has been described as an epidemic. At the global level, excess body weight is the sixth most important risk factor for ill health. Many adverse health outcomes are strongly associated with obesity. For more information about the authors and reviewers of this module, click here
We suggest that start with the learning objectives and try to keep these in mind as you go through the module slide by slide, in order.
Print-out the mark sheet.
As you go along, write your answers to the questions on the mark sheet as best you can before looking at the answers.
Award yourself marks as detailed on the mark sheet: one mark for each keyword (shown in red text) in the short answer questions and for every correct answer in the True/False questions.
How should I study this module?
Repeat the module until you have achieved a mark of >80%.
Finish with the formative multiple choice questionnaire to assess how well you have covered the material as a whole.
You should research any issues that you are unsure about. Look in your textbooks, access the on-line resources indicated at the end of the module and discuss with your peers and teachers.
Finally, enjoy your learning! We hope that this module will be enjoyable to study and complement your learning about obesity from other sources.
By the end of the module, you should be able to:
Define obesity in terms of body mass index (BMI)
Classify obesity in terms of body fat distribution and BMI values
Describe the burden of obesity on the world population
Discuss the role of lifestyle, genetic predisposition and other causal factors in the pathogenesis of obesity
Describe the association between obesity and type II diabetes, hypertension , cancer and reproductive disorders
Define childhood obesity and understand how it relates to adult obesity
Identify the treatment options available for people with obesity
Obesity is defined as the excessive accumulation of body fat.
There are a number of ways to measure body fat:
Measurements that are simple, cheap and appropriate for routine use include:
waist-to-hip circumference ratio
Indices derived from weight and height, e.g. body mass index
skin fold thickness using callipers (e.g. triceps, scapular)
Measurements of body fat that are expensive and require special equipment and highly trained personnel include:
How i s obesity measured?
C lassification of obesity (1) – ‘apples’ and ‘pears’
The apple shape:
also called “android”,
“ abdominal” or “central”
people with high waist-to-hip ratios are "apples", their body fat is distributed mainly on the upper trunk, the chest and abdomen giving the typical ‘apple shape’
individuals are mostly male
A waist-to-hip ratio >1.0 for men and >0.8 for women indicates an increased risk of cardio-vascular disease and diabetes mellitus
The pear shape:
also called “g ynaeoid” or
“ peripheral” obesity
people with lower waist to hip ratios are "pears“ - their body fat is distributed mainly on the lower trunk, the hips and thighs giving the typical ‘pear shape’.
individuals are mostly female.
associated health risks are minimal if any
Obesity can be classified into two groups on the basis of body fat distribution and the waist-to-hip circumference ratio. This simple classification is easily understood by the public and also predicts the risk of obesity-related health problems.
Classification of obesity (2) – body mass index (BMI)
The internationally accepted classification for obesity is the Quetelet's Index, also called the Body Mass Index (BMI)
The BMI is a measure of a person’s weight in r elation to height and it is calculated as:
weight divided by height squared (kg/m 2 )
BMI = w eight in kilograms = kg/ m 2 square of height in meters
Note: Although overweight is identified by a BMI of ≥ 25.0 kg/m 2 , the risks of obesity-associated diseases, such as diabetes, hypertension and dyslipidaemia, increase from a BMI of about 21.0 kg/m 2 .
Source: Adapted from WHO 1997 WHO classification of obesity Increased as follows:
Obesity, further classified as:
Increased Not increased Risk of co-morbidity
35.0 - 39.9
30.0 - 34.9
25.0 - 29.9 Overweight or pre-obese 18.5 - 24.9 Normal BMI (kg/m 2 ) Classification
oduction 1 Source: Weight Control Information Network , NIH A weight and height chart is a useful clinical tool to determine a person’s BMI
Advantages of BMI
Advantages of using BMI to classify obesity:
i t is low-cost and easy to use for health professionals for assessing individuals
it is commonly used to determine desirable body weights and allows people to compare their own weight status to that of the general population
it correlate s w ell with the amount of body fat as measured by more complex techniques
it predicts dangers associated with obesity; as BMI increases the risk for diseases increases
it is a useful screening tool to use at the population level and, because it is universally accepted, BMI reference data is available for many different populations
Disadvantages of BMI
Which of these men is at risk of ill health and why?
(b) (a) These men have the same height, weight and BMI, but have different percent body fat BMI calculated as follows: BMI = 84 = 84 = 28.4 kg/ m 2 (1.72) 2 2.96 Although BMI is equally high in both men, in (a) it is due to lean body mass whereas in (b) it is due to body fat. This shows that, used alone, a high BMI is not diagnostic of obesity. BMI also varies with age and sex in those <18 years. These are some of the disadvantages of using BMI to assess health risks. 1.72 metre Ht 1.72 metre 84 Kg Wt 84 Kg 28.4 BMI 28.4 Click to reveal answer
End of Section 1 Well done! You have come to the end of the first section. We suggest that you answer Questions 1 to 3 to assess your learning so far. Please remember to write your answers on the mark sheet before looking at the correct answers!
Question 1: Write “T” or “F” on the answer sheet. When you have completed all 5 questions, click on each box and mark your answer.
Obesity is the excessive accumulation of body fat
Body mass index (BMI) is the most universally accepted index of obesity
A woman with a BMI of 46.0 is overweight
To calculate the BMI of an individual, we need the weight, height and body fat distribution
A man with weight 76 kg and height 1.55 m is obese
Click for the correct answer a b c d e
Question 2: Complete the missing information on your mark sheet regarding the classification of obesity and the associated health risk Award yourself 1 mark for each right answer Click to Reveal Answers Health risk BMI Classification e ? Increased b? <25.0 d ? c ? Overweight 40.0 a?
Question 3: A 25 year old male athlete weighs 87.3kg and has a height of 1.7 5 m Write your answers on the mark sheet. When you have completed all 3 questions, click on the box and mark your answers.
Calculate his BMI
How would you classify his BMI ?
Is the classification of obesity based on BMI reliable for his man and, if not, why?
Click to Reveal Answers
The global burden of obesity
The obesity epidemic that began in the United States during the late 1970s is now occurring the rest of the world. Public health officials are concerned that obesity is reaching epidemic proportions in both adults and children . A high prevalence of obesity now occurs in the more affluent populations of countries that have food security problems and significant rates of under-nutrition . Current data indicate that in the world today:
there are > 1.1 billion overweight adults, and at least 312 million of them are clinically obese
10% of all children are either overweight or obese, while 17.6 million children under the age of five are estimated to be overweight
The prevalence of obesity has increased by about 10-40% in the majority of European countries in the past 10 years. Britain now has the highest obesity rate in Western Europe: 50% of the UK population are overweight (BMI 25.0 kg/m 2 ) and about 20% are obese (BMI 30.0 kg/m 2 ).
Obesity levels range from 5% in China, Japan, and certain African nations to over 75% in urban Samoa. Even in low prevalence countries like China, rates are almost 20% in some cities.
The USA has the highest obesity rate in the world. IN American adults, 50m are obese (BMI >30.0) and 6 m have class III obesity (BMI >40.0) . Obesity in adolescents has increased from 5% in 1966 -1970 to 14% in 1999.
Recent increase in the prevalence of obesity in the USA (1) Partners in Global Health Education Source: U.S. Center for Disease Control
Obesity in adults on the increase - worldwide Dramatic increases in obesity in recent years is not confined to the USA. These graphs illustrate the rise in obesity in adults in both rich and poorer countries. The growing epidemic of obesity - Source: IOTF Prevalence of obesity (%) Prevalence of obesity (%) England 16-64 yrs. USA 20-74 yrs. Former E. Germany25-65 yrs. W. Samoa (urban) 25-69 yrs. Japan 20+ yrs. Brazil 25-64 yrs.
1975 1989 1980 1966 1991 1995
1985 1989 1992 1978 1991
1975 1989 1980 1966 1991 1995
1985 1989 1992 1978 1991
Obesity in children living in poorer countries Africa & Middle East: 4 year olds Latin America and Caribbean: 4-10 year olds Source: adapted from IOTF unpublished data
Prevalence of overweight in 10-year old children in selected countries Source: adapted from IOTF unpublished data
Projected prevalence of obesity in adults by 2025 Source: IOTF data
The burden of obesity – costly, deadly…
The financial burden of obesity:
WHO data show that obesity
accounts for 5-10% of the total health
care budget in several developed
This is probably a low estimate as not all of the cost of management of obesity and its related problems can be calculated
In 2000, the U.S. spent $117 billion on obesity (9% of the national total health budget)
The morbidity and mortality burden of obesity:
Overall, about 2.5 millions deaths are attributed to overweight/obesity worldwide
In the UK, about 30,000 deaths are attributable to obesity. Ten times this figure occurs in the US where obesity is the second greatest preventable cause of death following smoking
Nearly 70% of cases of cardiovascular disease are associated with obesity
Obesity predisposes to an overall reduction of quality of life and premature death from diet related, chronic non-communicable diseases
End of Section 2 Well done! This is the end of the second section. We suggest that you proceed to answer question 4 to assess your learning further. Do remember to write your answers on the mark sheet before looking at the right answer!
Question 4: Write “T” or “F” on the answer sheet. When you have completed all 5 questions, click on each box and mark your answer.
obesity is a worldwide public health problem
obesity is not a major public health problem in developing nations
the highest rate of obesity is found in the U.S.A
obesity related problems account for less than 5% of healthcare budget in developed countries
obesity leads to premature death from diet related chronic communicable diseases
Click for the correct answer a b c d e
Calories in and calories out – the imbalance
The energy value of food can be expressed in calories. Obesity occurs when a person consumes more calories than h is/her body needs.
Excess calories are stored as fat and lead to weight increase. For example, consuming 3,500 calories more than the body needs results in a gain of 0.45kg of fat.
The factors which affect the balance between calories in and calories out differ from one person to another . Obesity is believed to result from a complex interplay of the following factors ( click each factor for details ) :
Socio-economic (lifestyle and diet)
Psychological and medical factors
Genetic factors We know that obesity tends to run in families, suggesting a genetic cause. Although, families also share diet and lifestyle, both of which contribute to obesity, research has shown that genetic factors account for as much 80% of the link between heredity and obesity .
Studies in adoptees and twins strongly
support this link:
Adults who were adopted as children have weights closer to their biological parents than to their adoptive parents
Monozygotic (identical) twins show a much stronger correlation in body weight than dizygotic (non-identical) twins
Source: NHS Health Scotland Back
Socio-economic factors and lifestyle (1)
Apart from our genes, environmental factors also contribute to the recent surge in obesity. The following changes in diets across the world play a major role:
increase in consumption of energy dense foods – containing animal fats
decrease consumption of complex carbohydrates and fibre - coarse grains, fruits
increase intake of alcohol and salt
In recent years, societies of the western world have enjoyed an over abundance of food – so people feast on larger portions at low prices. As this “affluence” creeps into the urban centres of the developing world, we are beginning to see a rise in obesity.
T he growth of the fast food industry has made an abundance of high fat, inexpensive meals widely available, resulting in a shift in stable foods from low quality staples (cassava, corn) to high quality refined staples (processed rice, wheat) .
Socio-economic factors and lifestyle (2)
Exercise – or the lack of it…
Urbanization and economic development in
the western world have led to t he ‘affluent
lifestyle ’ which include less physical activity.
the car - driving to work and school instead of walking or cycling
TV and computer games - long hours sitting watching
energy/time saving devices and machines (e.g. washing machines) reduce manual labour in the home
Source: http://www.aces.edu/dept/extcomm/newspaper/child-obesity.html Next
Socio-economic factors and lifestyle (3)
Socio-economic status has been found to relate to the risk of obesity in both adults and children . Although obesity is a feature of “affluence”, i n the UK, obesity is more common in poorer families.
An increasing incidence of obesity is being seen in the poor, developing countries of the world . In South Africa, obesity was found to be increased among the poorest women.
What are the reasons for this?
poorer families tend to eat energy dense, convenience foods – often they have no alternative as these tend to be low cost foods
people from lower socio-economic strata participate less in sports or physical activity in general and have lower weight control awareness
Cultural factors (1)
The cultural practice of placing young women in
‘ fattening rooms’ for months before marriage or
In fattening rooms, t he daily routine was to
sleep, eat and grow fat. The women spent their
time resting like beached whales and gorging
on a high-fat, high-calorie diets .
This practice has greatly reduced in recent
years in south-eastern parts of Nigeria.
Source: Where BIG is beautiful! Women who are not fattened are CURSED! National Examiner may 1, 2001 page 10 In certain culture s of the world ‘big is beautiful’. Obesity was a sign of wealth and well-being in the past and still is in many parts of Africa. In contrast to many Western cultures where thin is in, m any culture-conscious people in these parts hailed a woman's rotundity as a sign of good health, prosperity and allure. Next
The Japanese sumo wrestlers are well
known obese individuals. They achieve
their big size from an an elaborate rice-
based diet , fat-rich stew and lots of
Source: Print by Kunisada II Back
Psychological and medic al factors
Psychological factors are known to influence eating habits . Many people eat in
response to negative emotions, such as anger, sadness or boredom .
Metabolic and organic factors including drug therapies have been associated with obesity
as metabolic rate slows down, the tendency to gain weight increases . Slow metabolic rate is found with reduced physical activity, advancing age , and in females compared to males
certain medical conditions are associated with obesity: depression , hypothyroidism, Cushing’s syndrome, pituitary tumours,cerebral diseases including infections, hydrocephalus, as well as certain chromosomal anomalies – Down syndrome, Klienfelter syndrome
drugs that can cause weight gain include: corticosteriods , anti-depressant drugs , antipsychotics, oral contraceptive and progestagenic compounds, oral hypoglycaemic agents, insulin, antihistamines, blockers, pizotifen
End of Section 3 Well done! This is the end of the third section. We suggest that you proceed to answer questions 5 and 6 to assess your learning further. Do remember to write your answers on the mark sheet before looking at the right answer!
Question 5: Which of t he following factors will increase the risk of obesity in an individual ? Write “T” or “F” on the answer sheet, then click on each box to mark your answer.
consumption of fast foods
normal sized parents
Click for the correct answer a b c d e
Question 6: Several factors play a role in the pathogenesis of obesity. What risk factors match the following pictures ? a) ? d) ? c) ? b) ? Click to Reveal Answers
Obesity is a disease. Associations with obesity are protean. Click on each medical association for details
Medical associations of obesity
Hypertension and type II diabetes
coronary artery disease, and stroke, cancers and reproductive abnormalities
psychological complications including eating disorders, respiratory and other complications
Other effects of obesity
increase burden of disease world wide
increase financial burden on national health budgets
decrease in overall life expectancy
social effects including poor quality of life
Effects of obesity
Obesity - a known risk factor for several life-threatening medical conditions (1)
the risk of hypertension is five times higher among the obese than the non-obese population
studies confirm that 85% of hypertension arises in people with BMI values >25kg/m 2
increase body mass is associated with: increase blood volume, increase blood viscosity, increase release of angiotensinogen from adipocytes resulting in increase blood pressure
dietary fats consumed by obese individuals induce a direct rise in body cholesterol levels and blood pressure
Diabetes Mellitus (DM) :
the relation between obesity and type II diabetes (non-insulin dependent diabetes) has been established since the 1970s
excess fat deposits in obesity is associated with insulin resistance, glucose intolerance and premature type II diabetes
90% of patients with type II diabetes have BMI higher than 23kg/m 2
the risk of type II DM is greatly increase where there is a history of early weight gain (childhood obesity), android obesity, positive family history of DM, and maternal history of gestational DM
excess fat accumulation is linked with a rise in free oestrogen concentrations from the activity of the enzyme aromatase on sex hormones in adipose tissue
this high oestrogen level affects normal hormonal balance and accounts for menstrual irregularities, ovarian dysfunction, impotence and impaired fertility amongst men
6% of primary infertility is attributed to obesity in women
pregnancy complications, maternal and infant deaths, infant macrosomia have been found to increase by 3-10 fold in obese women
Obesity - a known risk factor for several life-threatening medical conditions (2)
Coronary artery disease and stroke:
The effect of obesity on cardiac function is thought to be due to a combination of hypertension, diabetes mellitus, dyslipidaemia and increased fat mass
The risk increases as BMI values exceed 21.0 kg/m 2. Studies show that heart failure in 14% women and 11% men is due to obesity
the risk for cancers is more among the obese than the non-obese population
estimates indicate that overweight and inactivity account for a quarter to a third of cancers of the breast, colon, endometrium, kidney and oesophagus
obesity worsens existing respiratory disease
sleep apnoea occurs in the obese due to mechanical obstruction from bulky fatty tissue around the neck
obesity has recently been sited as a risk factor for atopy
Obesity leads to joint pains and arthritis of the weight bearing joints – hips, knees
Obesity is also closely linked with the rapidly rising prevalence of non-alcoholic steatohepatitis in the developed world
The incidence of gall bladder disease and gall stones is higher in women with BMI of > 45 kg/m 2
Psychological features of obesity:
in US women obesity increases the risk of being diagnosed with major depression by 37%
low self esteem, anxiety, depression and obsessive behaviours are common among obese individuals especially women
obesity and depression are linked closely with two eating disorders: night eating syndrome and binge eating disorder (including bulimia nervosa). These need early recognition and early psychotherapy
Obesity - a known risk factor for several life-threatening medical conditions (3) Next
Other effects of obesity (1)
Increased body weight is now the 6th most important risk factor contributing to the overall burden of disease worldwide. Regions particularly affected are eastern Europe and America.
Obese individuals have a reduced life expectancy . Recent studies show that obesity reduces life expectancy by 7 years at age 40. The UK government’s recent estimates show that a BMI of 25kg/m 2 reduces the life expectancy of English men by two years.
Obesity is associated with an increase risk of premature death from several chronic diseases; as body weight increases to >20% of expected weight for height and age, the mortality risk has been shown to increase by 20% in males and 10% in females.
Apart from the ill health, premature death and disability resulting from obesity-related medical conditions, several billions of dollars are expended on their treatment . Obesity accounts for 5-10% of the total health care budget in several developed countries.
Other effects of obesity (2)
Obesity has serious deleterious effects on quality of life. There is the social stigma associated with obesity
20% of obese people are less likely to marry than their thinner counterparts
t he annual household income of obese people is nearly $7,000 less than that of thinner people
a n obese person is 10% more likely to live a life of poverty
With obesity there is restricted activity, exercise intolerance, pain, worry, low self esteem, and depression
End of Section 4 Well done! This is the end of the fourth section. Please answer questions 7. Do remember to write your answers on the mark sheet before looking at the right answer!
Question 7: Which of t he following are recognised associations of obesity . Write “T” or “F” on the answer sheet, then click on each box to mark your answer. a) Hypertension b) Type 1 diabetes c) Osteoarthritis d) Ovarian cancers e) Coronary heart disease Click for the correct answer a b c d e
What is childhood obesity ? Source: 1998-2005 Self Realization Publications
Defining childhood obesity (1)
Obesity in childhood has reached epidemic levels. In the US, it is the most common nutritional
disorder in children. Developing countries are also affected as the prevalence rises
among children of urban dwellers who emulate the ‘affluent western lifestyle’
As in adults, the WHO uses the body mass
index (BMI) as the standard definition of
obesity in children.
BMI is calculated with the same formula for children and adults, but the results are interpreted differently :
BMI for children, also referred to as BMI-for-age, is gender and age specific
BMI changes dramatically with age in children as body fat changes with growth, and between girls and boys with maturity
BMI-for-age, gender specific growth charts used for children and teens 2 – 20 years of age.
Defining childhood obesity (2)
BMI-for-Age is used for children and teens because of their rate of growth and development. It is a useful tool because :
BMI-for-age in children and
adolescents compares well to
laboratory measures of body fat
BMI-for-age can be used to track body
size throughout life
In children, obesity is defined as a BMI greater than the 95 th percentile for age while overweight is a BMI greater than the 85 th percentile for age > 95th percentile obesity 85th percentile to < 95th percentile Overweight 5th percentile to < 85th percentile Normal < 5th percentile Underweight BMI-for-age Classification
Risk factors for childhood obesity
obesity in one or both parents
infants of diabetic mothers
children from single parent families and families with fewer children
higher birth weight and rapid growth during infancy are associated with an increased prevalence of obesity
formula feeding during infancy ( breast feeding in women who did not smoke during pregnancy [ but not in women who smoked during pregnancy ] was significantly associated with a reduced risk of obesity )
sedentary lifestyle – increase TV viewing, computer games, car rides, including a reduction in number of mandatory physical education classes in schools especially in the US
increase consumption of sugar sweetened drinks , soda, snacks, energy dense fast food in large portions
The relationship between childhood and adult obesity
Thirty percent of childhood obesity leads to adult obesity and 70% obese adolescents become obese adults . The longer a child remains obese beyond age 3 years, the more likely that the obesity will persist into adulthood . This true life story illustrates this – reproduced with the kind permission of Mrs. S.
Born in the 60’s with a birth weight of 2.7kg ( normal weight ), she quickly became plump in infancy. Neither parent was overweight (father 82.6kg and1.52m; mother 50.8kg and 1.52m) From the age of 7, she was significantly heavier than her peers. In her early teens, she “weighed 88.9kg” and was advised by her paediatrician to join a slimming club. The weight gain persisted till adulthood. She is currently on nine different medications for obesity related problems Aged 13 – bridesmaid at wedding Married at age 40 weight - 178 kg, Height - 1.65m BMI = 66 kg/m 2
The relationship between childhood and adult obesity Now that you have read this story, list 5 obesity-associated problems that may occur in this woman.
End of Section 5 You have come a long way! This is the end of the fifth section. Please answer question 8. Do remember to write your answers on the mark sheet before looking at the right answer!
Question 8: The following are statements about childhood obesity. Write “T” or “F” on the answer sheet, then click on each box to mark your answer. a) obesity is not a problem in children b) BMI-for-age is used for children and teens because of their rate of growth and development c) the use of BMI to define obesity does not depend on gender d) BMI-for-age in children and adolescents compares well to laboratory measures of body fat e) t he longer a child remains obese beyond age 3 years, the more likely that the obesity will persist into adulthood Click for the correct answer a b c d e
Management of obesity
Effective management of obesity requires long-term strategies and an integrated, multi-disciplinary approach that includes community-based support for behavioural modification including diet and exercise. Research over the last decade indicates that a 5-10% reduction in body weight is sufficient to significantly improve medical conditions associated with obesity, such as hypertension, diabetes mellitus, and elevated cholesterol levels.
Currently there is lack of evidence of effective programmes for integrated management of obesity. But the following management options for the management of obesity exist:
bariatric s urgery
As always, “prevention is better than cure”. Recently the UK government has set a target to halt the rise in obesity in children aged ≤11 by 2010. Strategies for the prevention of childhood and adult obesity may need to address factors during or before infancy that are related to infant growth .
Management options (1)
the most common and conservative treatment for obesity utilizes a nutritionally balanced, low calorie diet
diet must include more fruit and vegetables, nuts, whole grains and exclude fatty and sugary foods
weight-loss programs recommend diets consisting of 1,200 to 1,500 calories per day, usually in the following proportions: 60 percent carbohydrate, 30 percent fat, and 10 percent protein
individuals must be carefully screened and medically supervised while on the diet (the degree of weight loss being dependent on individuals ability to adhere to dietary recommendations)
studies have shown that meal replacements are often more effective than very low calories diets, resulting in an increase in the amount of initial weight loss and enabling dieters to maintain their weight loss
Management options (2)
many eating and exercise habits combine to promote weight gain.
keeping a food diary that records times, places, activities, and emotions may be linked to periods of overeating or inactivity will reveal areas needing modification
lifestyle modification is best achieved when the affected individual is motivated, enthusiastic and supported to achieve set goals
patients are helped to avoid eating while on their feet, watching TV or
playing games. Eat home cooked meals rather than fast foods
motivated to walk rather than use cars, escalators, lifts. Reduce TV, computer game hours, and use of energy saving devices
research clearly indicates that regular exercise is the single best predictor for achieving long-term weight control
regular exercise leading to weight loss has been shown to improve blood pressure control, blood sugar levels in diabetics and other obesity-related complications
Management options (3)
It is recommended that anti-obesity drugs be used only :
in individuals aged 18-75yrs with a BMI of 30kg/m 2 or more
in individuals with a BMI of ≥27kg/m 2 with existing risk factors such as diabetes, cardiac disease, obstructive sleep apnoea or hypertension
in individuals with a BMI of >30kg/m 2 , in whom at least 3 months of managed care (supervised diet, exercise, and behaviour modification) fails to lead to significant reduction in weight
Two drugs have been licensed for use in the treatment of obesity:
Orlistat - prevents fat digestion and absorption by binding to gastrointestinal lipases; useful for those with a high intake of fat
Sibutramine - r educes appetite and increases thermogenesis ; recommended for those who cannot control their appetite
These drugs should not be used as sole therapy for obesity. Their use requires strict regular monitoring and must be discontinued if weight loss is <5% after 12 weeks of use or weight gain recurs while on the drugs
Anti-obesity drug treatment should not be used beyond a year and never beyond two years as few studies have examined the consequences of their long-term use
Gradual reversal of weight loss is known to occur on stopping pharmacotherapy
Management options (4)
Surgery may be a weight-loss option for patients who are severely
obese (with a BMI of 40 kg/m 2 or those with BMI 35kg/m 2 who suffer
from serious medical complications).
There are two accepted surgical procedures for reducing body weight: gastroplasty and gastric bypass; both reduce the stomach to a small pouch that markedly limits the amount of food that can be consumed at any one time.
Studies show that there is weight loss of 25 to 30% over the first year post operatively with rapid normalization of blood pressure and glucose in patients with hypertension and diabetes. This is maintained for about five years after surgery. However, longterm monitoring is needed and surgery is not without attendant operative risks.
End of Section 6 Well done! This is the last of the sections. Please answer questions 9 and 10. Do remember to write your answers on the mark sheet before looking at the right answer!
Question 9: Answer the following questions on the management of obesity
List the current management options for obesity
b) Surgery is sometimes considered in the management of obesity,
list the criteria for surgery
what surgical options exist?
Click to Reveal Answers
Question 10: Mark the following statements as either True or False
obesity management requires an integrated multi - disciplinary approach
regular exercise is the single best predictor for achieving long-term weight control
diet must exclude more fruit and vegetables, nuts, whole grains and include fatty and sugary foods
the criteria for use of pharmacotherapy is a BMI > 20 kg/m 2 with persistent co-morbidity
a 5-10% reduction in body weight is sufficient to significantly improve medical conditions associated with obesity
Click for the correct answer a b c d e
What Have I Learnt about Obesity? (1)
Obesity is the excessive accumulation of body fat, best defined by the Body Mass Index (or Quetelet's Index).
BMI is the universal and convenient measure of obesity. It is calculated as weight divided by height squared ( kg/m 2 ). The BMI-for-age is used to assess obesity in children.
In adults (age >18years), obesity is defined by a BMI of 30 kg/m 2 , and overweight by a BMI between 25 and 29.9 kg/m 2 . A child with a BMI-for-age >95 th percentile is obese while one with a BMI-for-age >85 th percentile is overweight.
The longer a child remains obese beyond age 3 years, the more likely that the obesity will persist into adulthood . 30% of obese children are also obese as adults. 70% obese adolescents end up as obese adults.
Obesity is believed to result from a complex interplay of several factors; genetic, environmental (lifestyle and dietary), cultural, socio - economic, psychological and medical conditions.
Obesity is a known risk factor for several life-threatening, chronic medical and metabolic conditions: hypertension, coronary artery disease, stroke, type II diabetes, cancers.
A 5 - 10% reduction in body weight has been shown to significantly improve medical conditions associated with obesity.
What Have I Learnt about Obesity? (2)
Obesity has reached epidemic proportions in several developed countries of the world and is also creeping up in urban cities of the underdeveloped world.
Globally, there are more than 1.1 billion overweight adults, and at least 312 million of them are clinically obese. 10% of all children worldwide are either overweight or obese, while 17.6 million children under the age of five are estimated to be overweight.
Rapid urbanization and economic development have led to changing lifestyles and diets across the world which promote excessive weight gain.
An increasing incidence of obesity is also being seen in the poor, developing countries of the world
Increase body weight is now the sixth most important risk factor contributing to the overall burden of disease worldwide
Sources of Information/images and References
Baird J, Fisher D, Lucas P, et al. Being big or growing fast: systematic review of size and growth in infancy and later obesity. BMJ 2005; S1:468-583
Bray G A, Popkin B M. Dietary fat intake does affect obesity! Am J Clin Nutr . 1998, 68:1157-73
Calle EE, et al. BMI and mortality in prospective cohort of U.S. adults. New England Journal of Medicine. 1999;341:1097–1105.
Cole TJ and Rolland-Cachera MF. In: Childhood and Adolescent Obesity. Burniat W, Cole T, Lissau I and Poskitt (Eds). Cambridge University Press, 2002
Haslam DW, Jones WPT. Obesity. L ancet 2005; 366:1197-1209
Garrow JS, Webster J. Quetelet's index (W/H 2 ) as a measure of fatness. International Journal of Obesity. 1985;9:147–153.
Gallagher D, et al. How useful is BMI for comparison of body fatness across age, sex and ethnic groups? American Journal of Epidemiology 1996;143:228–239.
Rudolf M C J, Hochberg Z, Speiser P. Perspectives on the development of an international consensus on childhood obesity. Arch Dis Child 2005; 90:994-996.
Stamatakis E, Primatesta P, Chinn S et al . Overweight and obesity trends from 1974 to 2003 in English children: what is the role of socioeconomic factors? Arch Dis Child 2005; 90:999-1004
World Health Organization. Physical status: The use and interpretation of anthropometry. Geneva, Switzerland: World Health Organization 1995. WHO Technical Report Series
WHO Obesity; Preventing and managing the global epidemic. Report of a WHO Consultation on Obesity. Geneva, 3-5 June 1997
Cartoon characters from the WeightWise campaign of the British Dietetic Association.
Drent ML, van der Veen EA. Lipase inhibition: A novel concept in the treatment of obesity. Int J Obes Relat Metab Disord 1993; 17:241-244.
Authors and reviewers
Dr. Affi ong Ben-Edet, Consultant Paediatrician and Lecturer I, University of Uyo Teaching Hospital, Akwa-Ibom State, Nigeria
Dr. Ike Lagunju, Consultant Paediatrician and Associate Lecturer, College of Medicine, University of Ibadan, Ibadan, Nigeria
David Lewis, Learning Technologist, The School of Medicine, Swansea University, Swansea, UK
Dr. Stephen Allen, Senior Lecturer in Paediatrics and Honorary Consultant Paediatrician, The School of Medicine, Swansea University, Swansea, UK
Professor Rhys Williams, School of Medicine, University of Wales Swansea, UK
Dr Jeffrey Stephens, Senior Lecturer in Diabetes & Honorary Consultant Physician, Morriston Hospital Swansea, UK
We would like to acknowledge the of the Association of Commonwealth Universities, London for awarding the Fulton Fellowship which supported Dr. Lagunju in developing this module Back
Answer to Question 1a This statement is True . The body naturally stores fat under the skin and around joints and internal organs. Fat provides energy, insulation and protection. However, accumulation of excess body fat results in obesity and is associated with increased health risks. Back
Answer to Question 1b This statement is True . Body mass index (BMI) is the most widely used index of obesity. Back
Answer to Question 1c This statement is False . This woman is classified as Class III obesity. This is associated with severe health risks. Back
Answer to Question 1d This statement is False . T he BMI is calculated using only weight and height. Back
Answer to Question 1e This statement is True . T his man is classified as obesity Class I. Back
Answer to Question 2 Back Health risk BMI Classification e) Not i ncreased Increased b) Severely increased <25.0 d) Normal c) 25.0 - 29.9 Overweight 40.0 a) Obesity Class III
Answer to Question 3
BMI = 87.3 kg = 28. 5 kg/m 2
(1. 75 m) 2
H is BMI lies in the “ overweight range” (25 – 29.9 kg/m 2 )
The likely reason for the increased BMI in an athlete is an increase in lean muscle mass
BMI does not distinguish between lean body mass (accumulation of muscle mass) and body fat. Hence, this athlete is wrongly classified as overweight.
Answer to Question 4a This statement is True . O besity occurs in all countries in the world. There are currently 1.1 billion adults and 10% children classified as overweight or obese in the world. Back
Answer to Question 4b This statement is False . O besity is a significant health problem in both the developed and developing world . Back
Answer to Question 4c This statement is True . The United States of America has the highest obesity rate in the world . Back
Answer to Question 4d This statement is False . Obesity and its related health problems place serious financial burden on the health budget of a country. Back
Answer to Question 4e This statement is False . O besity leads to premature death from diet related non- communicable chronic diseases such as type II diabetes mellitus, cardiovascular disease and hypertension. Back
Answer to Question 5a This statement is True . Physical inactivity reduces the utilisation of calories, the excess is stored up as fat - obesity Back
Answer to Question 5b This statement is True . Fast foods often are over-processed foods, with a high concentration of fat, salt & refined sugar, all of which promote excessive weight gain . Back
Answer to Question 5c This statement is True . Psychological depression has been associated with an increased risk of obesity, consequent on increased food intake Back
Answer to Question 5d This statement is False . Genetic predisposition is a major risk factor for obesity. A positive family history of obesity in one or both parents is associated with increase risk of obesity Back
Answer to Question 5e This statement is False . Hyperthyroidism is associated with weight loss. Hypothyroidism is associated with weight gain due to reduced metabolic rate . Back
Answer to Question 6 (a) Socio-economic (Dietary and Lifestyle) factors (b) Psychological factors (c) Cultural factors (d) Genetic factors Back
Answer to Question 7a This statement is True . A n increased risk of hypertension is associated with obesity Back
Answer to Question 7b This statement is False . O besity is associated with Type II and NOT Type I diabetes. Obesity is associated with insulin resistance, glucose intolerance and early onset of type II diabetes Back
Answer to Question 7c This statement is True . O besity results in increased risk of osteoarthritis, particularly affecting the weight-bearing joints Back
Answer to Question 7d This statement is True . O bese women are at increased risk of ovarian cancers Back
Answer to Question 7e This statement is True . Coronary heart disease strongly associated with obesity Back
Answer to Question 8a This statement is False . Obesity in childhood has reached epidemic levels. In the US, it is the most common nutritional disorder in children and its prevalence is increasing. Back
Answer to Question 8b This statement is True . Using BMI-for-age accounts for the changes in body fat that occur normally with growth and development in children Back
Answer to Question 8c This statement is False . BMI-for-age is gender specific. Age-related changes in body fat differ between boys and girls. Use gender specific BMI-for-age chart when assessing obesity in children. Back
Answer to Question 8d This statement is True . Studies have shown that BMI-for-age in children and adolescents compares well to laboratory measures of body fat . Back
Answer to Question 8e This statement is True . Studies have shown that t he longer a child remains obese beyond age 3 years, the more likely that the obesity will persist into adulthood. Back
Answer to Question 9 Back
Management options for obesity include:
behavioural modifications including diet and physical activity
Surgery may be a weight-loss option for patients
the criteria for surgery include:
Severe obesity (BMI of 40 kg/m 2 )
Occurrence of serious medical complications (with a BMI 35kg/m 2 )
the two accepted surgical procedures for reducing body weight are : gastroplasty and gastric bypass
Answer to Question 10a This statement is True . Effective management of obesity requires the involvement of a multi-disciplinary team and longterm strategies Back
Answer to Question 10b This statement is True . Research clearly indicates that regular exercise is the single best predictor for achieving long-term weight control Back
Answer to Question 10c This statement is False . Diet must include more fruit and vegetables, nuts, whole grains and exclude fatty and sugary foods Back
Answer to Question 10d This statement is False . The criteria for use of pharmacotherapy is: a BMI ≥ 27kg/m 2 with persistent co-morbidity or a BMI >30 kg/m 2 Back
Answer to Question 10e This statement is True . Research over the last decade indicates that a 5- to 10-percent reduction in body weight is sufficient to significantly improve medical conditions associated with obesity Back