Atkins & Low-Carb – Part 5

With the popularity of low-carb diets today, most of us have at
one time or another considered cutting carbs. In this series of
articles we have discussed ‘low-carbing’ and whether or not it’s
right for everyone.

In this article we’re going to talk about carbohydrates and how
they are stored in the body. Does a large supply of excess carbs
make us fat?

Many people believe that only dietary fat will lead to body fat.
False! Actually, eating more calories than your body needs to
perform daily activities and daily metabolism is what causes
body fat. It is as simple as putting 20 gallons of gas in a 15
gallon gas tank…..the excess must go somewhere. In the case of
human nutrition, the excess is stored as fat.

Just as excess protein can be stored as body fat, excess
carbohydrate can be stored as body fat. Unfortunately for the
American public, our consumption of simple carbohydrates has
skyrocketed over the last ten years! Too many of us took the
popularity of the low-fat and fat-free diets as an excuse to
fill up on empty carbo-calories. After all, it’s okay to eat the
entire package of licorice since it’s all fat free….right?
Again, False!

Carbohydrates that the body cannot use are stored as body fat,
plain and simple. Carbohydrates usually are ingested in the
forms of polysaccharides (starches), disaccharides (sucrose and
lactose) and monosaccharides (glucose and fructose). Essentially
what occurs in the digestive process is a breakdown of the
polysaccharides and disaccharides to the monosaccharides. The
primary site of digestion is the small intestine, where the
monosaccharides are then absorbed into the blood. Of the three
monosaccharides, glucose is of most importance to human
physiology. This is called blood sugar. Fructose and galactose
are converted to blood glucose either in the intestinal wall or
the liver.

A high-carbohydrate meal will lead to a rapid increase in the
blood sugar level, usually within an hour. Naturally, the higher
the food is on the glycemic index (refined sugars), the higher
the blood sugar level will rise. The maintenance of a normal
blood sugar level is very important for proper metabolism. The
human body regulates blood sugar levels by a hormone called
insulin. The rises in blood sugar levels stimulate the pancreas
to secrete the hormone insulin into the blood. Insulin then
facilitates the uptake and utilization of blood sugar by various
tissues in the body, most notably the muscles and adipose tissue.

The fate of blood sugar is dependent on many factors, with
exercise being one of the most important.

1) Blood sugar may be used for energy, particularly by the brain
and other parts of the nervous system.

2) Blood sugar may be converted to either liver or muscle
glycogen. Liver glycogen may then be later converted to blood
sugar. Muscle glycogen is, for the most part, locked into the
muscle cell once it enters, where it is converted to energy.

3) Blood sugar may be converted to and stored as fat in the
adipose tissue. This situation occurs when the dietary
carbohydrate, in combination with caloric intake of other
nutrients, exceeds the energy demands of the body, and the
storage capacity of the liver and muscles for glycogen.

4) Some blood sugar also may be excreted in the urine if
excessive amounts occur in the blood, because of rapid ingestion
of simple sugars.

So, what happens if we don’t consume enough carbohydrates?
Because the carbohydrate stores in the body are rather limited,
and because blood sugar is normally essential for optimal
functioning of the central nervous system, it is important to be
able to produce blood sugar or glucose internally if the stores
are depleted by starvation or a zero-carbohydrate diet. This
process is called gluconeogenesis, meaning the formation of
glucose. In this process, protein is converted to glucose, and
fat is converted to glucose by breaking down glycerol in the
liver. The by-products of carbohydrate metabolism, lactate and
pyruvate, may also be converted back to glucose in the liver.

With this understanding of how carbohydrate is metabolized in
the body, it is clear that low-carb or no-carb diets may lead to
decreased levels of energy.

Low-carb diets, however, have been proven to take off the
weight. In some cases, weight loss has been dramatic when the
subjects abruptly switched to a no-carb diet. Such rapid weight
loss is attributed to water loss. Low carbohydrate intake
depletes liver and muscle glycogen (stored sugars) and water
molecules linked to these sugars. This depletion triggers a drop
in body weight.

Especially during the introduction phase of a low-carb diet (2
weeks), the dieter is encouraged to eliminate virtually all
carbohydrates from the diet. Even a slight intake of high
glycemic foods during this phase would cause immediate weight
gain by rebuilding glycogen stores.

Because carbohydrate is the body’s preferred fuel source, this
first phase of the diet would most certainly challenge exercise
enthusiasts.

So, is the low-carb lifestyle right for you? Maybe. We hope that
this series of articles has helped you understand low-carb diets
and their potential impact on the body.

SOURCE: (International Sports Sciences Association; Frederick C.
Hatfield, Ph.D.; 2001)

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