Optimum Nutrition - Winter 2021 - PREVIEW

Feature
IN BRIEF
• Research suggests insulin
resistance rather than overeating is
the primary cause of obesity.
• Insulin resistance can also be
driven by stress and poor sleep.
• Insulin resistance drives chronic
diseases including heart disease,
dementia and type 2 diabetes.
• A low carb diet can support insulin
sensitivity and reverse type 2
diabetes in some instances.
• Glucose tolerance (i.e. the amount
of carbohydrate your body can
handle) varies between individuals.
Growing evidence suggests that our
bodies do not act like bank accounts
for calories. One recent paper,
published in the American Journal of
Clinical Nutrition, suggests that insulin
resistance, rather than overeating, is
the primary cause of obesity. It also
lays the blame for obesity on excessive
consumption of foods with a high
glycaemic load (GL); in other words,
rapidly digestible carbohydrates. These
foods, the researchers propose, cause
changes to the hormone insulin, which
changes metabolism, and drives fat
storage, weight gain and obesity. 1
So this January, rather than focusing
on how much we’re eating, could
focusing on what we’re eating and how
it affects our insulin be the key to losing
weight?
Lock and key
Insulin is a vital hormone, with the
essential job of getting rid of sugar in
our bloodstream after we eat. Think of
it like a lock and key mechanism. Sugar
(glucose) in the blood is trying to get
through the door of the cell. But to get
inside, it must have a key to open that
door. Insulin is that key.
But what happens if you have too
much sugar in your bloodstream? Then,
the doors of the cell become resistant
to the insulin — think of the keyhole
getting rusty through over-use. This
means that the pancreas has to pump
out more insulin to try to get the cells to
unlock, thus elevating levels of insulin.
Excess sugar can also get pushed
into belly fat and the liver. The latter
is what’s known as non-alcoholic fatty
liver disease (NAFLD); a condition
that affects around a quarter of
the developed world. NAFLD also
interferes with the action of insulin
itself, which means the pancreas has to
produce even more insulin to get rid of
all the sugar from your blood.
Insulin acts as a key for opening cells to store glucose away as energy (left); when cells
become 'insulin resistant', glucose remains in the blood, raising blood sugars (right)
Insulin resistance can be considered
a spectrum as, over time, more and
more cells become resistant to insulin.
Eventually, the pancreas gets worn out
and can no longer produce enough
insulin to overcome the cells’ resistance.
The result is type 2 diabetes.
The driver of disease
Whilst not all of us might be diagnosed
as diabetic, Bikman’s book raises the
question as to whether many of us are
somewhere on this insulin resistant
spectrum, and that this is driving
chronic disease.
“People don’t die from insulin
resistance,” Bikman tells Optimum
Nutrition. “They die from the diseases
that insulin resistance is causing.
Alzheimer’s disease, heart disease; those
are the complications that are arising
from the insulin resistance, which
ultimately prove lethal.”
When it comes to heart health, for
example, Bikman says that insulin
resistance promotes higher blood
pressure. “It does this through several
different mechanisms. One is forcing
the kidneys to hold onto more salt than
normal, which means they’re forced to
hold onto more water as well. And if
they’re holding onto more water, blood
pressure starts to climb.”
Insulin also helps to promote the
dilation of our blood vessels, he adds.
However, when the blood vessels
become insulin resistant, they stay
constricted and can’t move as much
blood as they did before, causing blood
pressure to increase.
“People don’t die from insulin resistance…They die from the diseases
that insulin resistance is causing…"
Image: Elyomys © 123rf.com
Image: Simpson33 © 123rf.com
OPTIMUM NUTRITION | WINTER 2021/22
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