|
|
Heartline Magazine July - September 2005
Obesity
By Dr. Anselm Hennis
Nearly 1 billion persons worldwide are overweight!
Overnutrition is, however, not a new phenomenon. Overweight has traditionally
been regarded as a good thing ¡V a sign of good health and prosperity.
Stone-age artefacts of corpulent women in the Palaeolithic era dating some
25,000 years ago, have been found in sites across Europe. However, larger
numbers of humans are now obese than has ever been evident before. We live in an
era of a new and expanding global epidemic of obesity.
Does obesity have any significance?
At the beginning of the 20th century, analyses of life insurance data clearly
showed that obesity was associated with increased risk of premature death.
Obesity also increases the likelihood of many diseases including 1)
cardiovascular disease ¡V including hypertension, heart disease, stroke and
peripheral arterial disease; 2) diabetes; 3) elevated cholesterol and associated
disturbances 4) gall bladder disease - i.e. gall stones 5) certain cancers ¡V
breast cancer (post-menopausal), endometrial (uterine), ovarian; possibly ¡V
gall bladder and cancers of the large bowel (colon and rectum); 6) arthritis
(and also gout); 7) respiratory problems such as obstructive sleep apnoea; 8)
psychosocial problems; and not to be ignored, 9) social bias, prejudice and
discrimination.
What are the causes of obesity?
Obesity may be considered a state of imbalance where more energy has been taken
in and stored, than the energy expended (or burnt off) over a considerable
period of time, leading to a state of positive energy balance. Energy Intake is
comprised of all food and drink consumed. Of the food groups, fat has the
highest energy value (9 kcal/g), while protein and carbohydrate have the same
energy value (4 kcal/g).
Energy expenditure consists of the 1) energy expended in
physical activity and 2) energy used to maintain the basal metabolic rate (BMR)
needed at rest to keep the various bodily functions (e.g. heart pumping, brain
working, respiration etc.) operative.
The only means of losing weight sustainably, require a
decrease in food intake and increased physical activity.
We can all identify individuals who can eat continuously and
never seem to gain weight, and there are others who only have to walk past the
Bar-B-Q barn to gain 10 lbs. This relates to individual (biological)
susceptibility to becoming obese. Because of various inherited characteristics,
persons exposed to identical conditions will have differing chances of becoming
obese.
How is obesity defined?
Obesity is defined as the body mass index (BMI), which is calculated as weight
(kg) divided by the height (metres) squared. An adult weighing 154 lbs (70 kg)
and of height 5 ft 9 inches (1.75 m) has a BMI of (70/(1.75*1.75)) 22.9 kg/m2.
BMI ranges from: low <18.5 kg/m2; normal 18.5 ¡V 24.9 kg/m2; overweight 25 ¡V
29.9 kg/m2; to obese >30 kg/m2. There are however, important limitations in that
BMI cannot differentiate body mass due to increased muscle bulk, and it may be
difficult to interpret in e.g. muscular individuals.
A healthy weight may be defined as a BMI between 18.5 and
24.9 kg/m2. A recent World Health Organisation (WHO) report suggests that
non-smoking individuals will have an optimum life expectancy by maintaining a
BMI at about 20 kg/m2 throughout life. At the level of a population, WHO
recommends that the population BMI should range between 21 and 23 kg/m2.
Another measure of obesity is the waist circumference (WC),
which measures abdominal fat and is linked to high risk of diabetes, elevated
cholesterol and heart disease. High WC gives rise to the so-called apple shape
(exemplified by the ¡¥beer belly¡¦ in men).
WC and sex-specific risk of increased metabolic
complications:
Increased risk Substantially increased risk (MS)
Men „d94 cm (37 in) „d102 cm (40 in)
Women „d80 cm (32 in) „d88 cm (35 in)
What then is a healthy shape? A narrow waist based on the
cited cutpoints. For women WC<32 inches (or 80 cm) and men WC<37 inches (94 cm).
What is the relevance of obesity to Barbadians?
A study was conducted in the early 1990¡¦s of hypertension in populations of the
African diaspora and included persons living in cities in West Africa, Caribbean
¡V Jamaica, Barbados and St. Lucia, USA ¡V Chicago, UK ¡V Manchester. It
demonstrated a number of important new findings. The rates of hypertension and
diabetes increased from Africa, across the Caribbean to the USA and this was
linked to increasing rates of obesity. Rates of obesity in Barbados were
exceeded only by those in the USA in African-Americans. Among Barbadians, 60% of
women were overweight and 30% obese, compared to 30% of men being overweight and
10% being obese. Overweight is twice as common in women than men and obesity is
three times as common among women than men. While the recommendations are for a
mean population BMI to range between 21 and 23 kg/m2, men had an average BMI of
25.8 kg/m2 and women, 29.3 kg/m2. Higher rates of obesity in Barbadian women
mirror the higher rates of diabetes and hypertension.
At the beginning of the 20th century 3 generations ago,
Barbados was considered the ¡¥unhealthiest colony in the British empire¡¦.
Infant malnutrition and infectious disease were still major killers by the
1950s. However by the time of the nutrition survey in the 1980s, Dr. Frank
Ramsey recognised that we were on the verge of an epidemic of the other type of
malnutrition ¡V overnutrition. We are once again infamous; comments were made in
Newsweek in August 2003 about the allocation of approximately half of the health
budget for medications to treat obesity related disorders.
Few of us walk, nightly traffic jams identify the routes to
fast food joints, and we seem to be oblivious of the need to modify our
lifestyles in order to live both better and longer. Indeed we celebrate
overnutrition with the Miss Big and Beautiful contest uncaring about the
subliminal messages which this pageant broadcasts. There is a clear view that in
the USA, the obesity epidemic will reverse many of the gains in the public
health achieved over the past century and this will also be our reality here in
Barbados. Our rates of obesity are similar to those in the USA and other more
developed regions, our principal cause of death nationally remains
cardiovascular diseases, and we have to face the reality that unless we modify
the way we live our gains in life expectancy will be offset by longer periods of
ill health which will cost each and every one of us dearly. There will be many
more persons requiring treatment for heart disease and stroke, and these persons
will be us. We have seen the onset of the obesity epidemic in adolescents and
the evolution of type 2 diabetes in children, and unless we make dramatic
changes, this will merely be the beginning.
We have a clear sense of the problem, and we all know what
is required. While the government has committed its support to a Chronic Disease
Commission which will have the mandate of translating policy into action to
reduce the burden of obesity-related ill health nationally, each citizen has to
play his or her part individually.
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| |
|
|
|
|
 |
|
