Global Health Asia-Pacific September 2020 September 2020 | Page 53

Excess weight doesn’t always equate to poor health
how our diet interacts with our own genetics and
metabolism.
Though the vast majority of people with obesity
don’t have a single gene that explains why they
maintain a very high body weight, a combination
of several genes and the way they interact with the
environment, something called epigenetics, are
thought to play an important role in many instances.
For example, some of our ancestors who had to
survive periodic famines probably developed the
lifesaving ability to absorb all the available calories
from their limited food supply and passed it down
through generations, explained Dr �ody Dushay, an
endocrinologist and obesity specialist at �eth Israel
Deaconess Medical Centre, to Global Health Asia-
�aci�c. �ut in a setting of food excess, this ability
increases the chances of becoming obese.
Genetic and highly individualised factors might
explain why similar eating and exercise habits lead
some people to gain much more fat than others or why
disparate things, like the use of steroidal medications
or pregnancy, have markedly variable effects on
people’s weight.
Metabolism is another powerful and hard-to-control
force that is believed to shape our body weight. Some
research shows that individuals who slim down see
a reduction in their metabolic rate, resulting in their
burning fewer calories, while increased hormone levels
make them hungrier in order to bring them back to
their previous weight. �xperts think this is the result of
still unknown physiological processes that establish a
so-called weight set point that each individual hovers
around.
“It’s unclear when in life this set point gets
established,� said Dr Dushay. �It probably relates to
gender, age, and genetics, but no one really knows.�
While removing some burden of personal
responsibility from people with obesity, this theory
provides strong biological reasons for the di�culty
people face in shedding pounds and keeping them
off � a familiar struggle that’s frustratingly evident in
the dismal track record of diet programmes over the
long term.
A recent review of more than 100 studies measuring
the effectiveness of 14 popular diets in about
22,000 overweight or obese adults shows that all of
them offer modest weight-loss results and positive
improvements in heart health at the six-month mark,
but �at 12 months the effects on weight reduction and
improvements in cardiovascular risk factors largely
disappear,” the authors wrote in The British Medical
Journal.
“If you do follow a very low-calorie diet, say a
500-800 calorie per day diet, in the short term almost
anyone will lose weight because that’s too few calories
coming in,� explained Dr Dushay. The problem, she
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