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Insulin
is a hormone secreted by the pancreas. It helps the body utilize
blood glucose (blood sugar). Think of insulin as a key. Every cell
has a 'lock' (receptor) on it that opens a door that allows glucose
to pass from the bloodstream into the cell. Once the glucose has
entered the cell, it is used for energy. Glucose can be stored for
future use by the liver or muscles in the form of glycogen.
The muscles and liver are the main storehouses of glycogen. Talk
about efficiency of design. The very mechanicals that motivate us
are also storage units! The power source is located right where
the muscle needs it. Low-latency power on-demand! Which is great,
but the most important thing to remember here is that once the muscle
storage units and liver are full of glycogen; the remaining glucose
in the bloodstream that is not being used by the brain or other
vital organs usually gets stored as fat.
As a person gains body fat, the cells of their body become less
sensitive to insulin. Insulin
resistance occurs when the normal amount of insulin secreted by
the pancreas is unable to 'unlock' the doorway of the cells. As
a result, the pancreas must secrete higher and higher levels of
insulin in order to overcome this widespread insulin resistance
as it tries to maintain normal blood glucose levels. High levels
of insulin signal the liver to convert carbohydrates into fat, following
a meal or snack containing carbohydrates. In turn, these fats are
shipped to your fat cells, contributing to weight gain and increased
body fat.
What can cause the body to become insulin resistant? Genetics can
obviously play a role, but I believe it has a LOT to do with the
typical American's poor diet consisting of mainly mid-to-high glycemic
carbs, irregularly spaced feedings and lack of regular exercise
that are mainly to blame. So it really becomes a Catch-22 situation
for a mostly sedentary overweight person. Popular low-fat diets
alone don't get results because your body is conditioned to convert
carbohydrates into fat, due to high levels of circulating insulin.
The other negative effect increased fat storage and no exercise
is the increasingly lower BMR (Basal Metabolic Rate) that occurs
because of this lifestyle. And that's a death sentence for the typically
weak and half-stepping fat-loss efforts; A.K.A. "diet"
that most sedentary types try.
But the really sad thing is that these folks won't exercise or
exercise correctly even it they do. You hear people speak as if
diet is the only thing they need to be concerned about. That type
of thinking doesn't help. Remember it was not just the diet, but
also the lack of exercise that got them into that state.
And it's going to take both diet AND exercise to get them out of
it...
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