When we talk about "global issues", it's
generally to do with trade or the environment. But there's another area
where global trends are apparent - the whole world is getting fatter!
This trend translates to an increased risk of a number of diseases
including diabetes. The prevalent rates of obesity and diabetes have
increased dramatically in the last decade and are expected to double in
the next 25 years.
According to Dr Wayne Calloway, Associate Clinical
Professor of Medicine at George Washington University, a gradual
increase in the incidence of overweight and obesity was observed
worldwide from the 1960s to the 1980s. "However, the last fifteen years
have seen a rapid increase, most notably in children," said Dr Calloway
speaking at the Seminar on Risk Assessment and Dietary Use of High
Intensity Sweeteners in Thailand in November 1999.
"In the United States, nearly one in four children is
overweight," said Dr Calloway. "There has been a doubling of the
incidence of obesity in the United States and Japan between 1973 and
1994. Even Thailand experienced a 12-16 percent increase in obesity
between 1991 and 1993."
The picture is similar when the prevalence of
diabetes is looked at. The World Health Organization of the United
Nations has projected a tripling in the incidence of diabetes mellitus
in Southeast Asia over the next 25 years.
Multiple factors
What is the cause of this epidemic and how can we
arrest it?
There are multiple factors that contribute to both
obesity and diabetes including genetic makeup, activity levels and
energy intake. According to Dr Calloway, one of the most important risk
factors for both obesity and diabetes is a lack of physical activity or
more specifically, problems in balancing energy intake and energy
expenditure.
"In the United States, energy intakes have decreased
over the past decade or so, however levels of energy expenditure have
fallen even more," said Dr Calloway. Studies in the United States have
linked an increase in physical activity with lower body weights.
Limiting television viewing and computer play to less than an hour a day
is associated with a reduction in body weight in children, according to
Dr Calloway.
Fat distribution important
Recent studies point to the distribution of body fat
as being more important than overall body weight in the development of
insulin resistance and, therefore, diabetes There are two types of body
fat distribution - android and gynoid. The android shape is often
referred to as the "apple" shape and is the shape most often associated
with an increased risk of diabetes. Body fat is distributed mostly in
the upper half of the body and in the abdominal area. The "beer belly"
found on many men typifies this body shape.
Women are more likely to have a gynoid or "pear"
shape where most of the fat is found around the thighs, hips and buttock
area. While many women complain about having large hips, this type of
body distribution is actually healthier than the apple shape and does
not appear to be linked to an increased risk of diabetes.
Genes or environment?
Should we point the finger of blame for an increase
in diabetes at our genes or today's environment? According to Dr
Calloway, both factors are important. "Genes only express themselves in
an environment," he said. "When environmental change occurs, those with
a genetic predisposition are the most susceptible."
Several studies have indicated that certain ethnic
groups may be more at risk of developing diabetes. Such groups include
those of Asian extract, American Indians, Pacific Islanders and
Australian aborigines. When these groups are exposed to an environment
that increases the risk of diabetes - such as low activity levels and
high-energy diets - the risk of developing diabetes is increased
significantly.
Preventing diabetes
Dr Calloway highlighted the need for better screening
of both individuals and populations at risk of diabetes, especially
overweight children. "This data needs to be culturally-specific," he
said. "Countries need to collect information on the normal weights and
heights of their population. They also need data on waist circumferences
and to look at any correlation between insulin resistance and the above
parameters."
Reversing the worldwide epidemic in diabetes means
arresting the alarming rise in obesity. While the latest fad diets will
always exist, the basic advice of nutritionists has remained the same
for years - balance what you eat with how much energy you burn up.
"Severe calorie restrictions don't usually work in
controlling body weight in the long term," said Dr Calloway. "The body
responds by reducing metabolic rate to conserve energy and people tend
to compensate by snacking more or taking in more calories at the next
meal."
Getting more active will not only burn up extra
calories; it also helps reduce abdominal obesity (the apple shape) and
lowers the risk of developing diabetes. New food products can help in
weight control. High intensity sweeteners (often referred to as low
calorie sweeteners) and fat substitutes can help in reducing calories in
the diet plan.
"A healthful diet that tastes good and is culturally
appropriate, combined with physical activity, is the best advice for
those wishing to reduce the risk of diabetes," concluded Dr Calloway.
RISK FACTORS FOR DIABETES MELLITUS
OR DIABETES MELLIT
- Family history of diabetes
- Being overweight or obese
- Race/ ethnicity - Asians, Australian Aborigines and Pacific
Islanders seem to be at increased risk
- Age greater than 45 years
- Impaired glucose tolerance
- High blood pressure
- Low levels of "good" (HDL) cholesterol
- Raised triglyceride levels
- History of diabetes during pregnancy or giving birth to large
infants (more than 9 pounds in weight)
- Being physically inactive
