Supporters of the Atkins Diet claim that a low
carbohydrate diet is a safe and effective method for losing weight.
This article evaluates the low carbohydrate diet and specifically the
claims made about ketosis.
<h4>The Low Carb-Ketosis Link</h4>
By severely limiting carbohydrates in your diet,
the main energy source used by your body, glucose, drops to low levels.
In return, insulin levels also drop. With low glucose and low insulin
levels, the body turns to alternative sources of energy.
Because of a significant change in your body's
chemistry when on the Atkins Diet, certain metabolic pathways are
turned "on" that are normally not "on" or run at very low levels. One
such pathway involves the breakdown of fat, called Beta-Oxidation of
Fats.
Now, normally fats are broken down to produce
energy when your body senses a need. But in the context of a low Carb
diet, the normal breakdown pathway of fats is altered and an
alternative pathway kicks in. This alternative pathway produces what
are called ketone bodies.
Ketosis is the term used to describe when ketone
bodies are circulating in your bloodstream. The ketone bodies can be
used as alternative sources of energy by, most importantly, your brain.
In case you might be curious, the three ketone
bodies produced by this alternative pathway for breaking down fat are
acetoacetate, beta-hydroxybutyrate, and acetone. These ketone bodies
are formed in your liver and then are transported to other tissues,
mainly the brain. In your brain, they are converted back to a form that
can provide direct energy during times of starvation.
Here is the whole process...
<ol><li>Atkins Diet lowers glucose and
insulin (the body's main energy source)
<li>Alternative pathways are turned
"on" to provide energy
<li>One alternative pathway breaks
down fat and produces ketone bodies
<li>Ketone bodies represent the
state called ketosis
<li>The brain uses ketone bodies as
an alternative source of energy</li></ol>
So, the Atkins Diet (and any low Carb diet)
produces a low energy state (low glucose) that causes the breakdown fat
using an alternative pathway that leads to the development of ketosis.
So far it sounds pretty good. By limiting Carbs in
your diet, you can essentially force your body into breaking down
stored fat, the very thing you need to get rid of to lose weight.
But there are problems...
<h4>Atkins Diet and Toxicity</h4>
Ketone bodies are toxic. Many supporters of low
Carb diets claim that ketosis is safe. They state that they are natural
byproducts of fat breakdown and even babies have high levels of
circulating ketone bodies.
First, they are not natural by-products of fat
metabolism. The normal beta-oxidation of fats does produce ketone
bodies but these are incorporated into the normal cycle of energy
production, called the Krebs cycle. When ketone bodies are circulating
in your bloodstream, it signals an abnormal physiologic state, called
starvation. They are not incorporated into the normal energy cycle, the
Krebs cycle, and spill into the bloodstream.
Just because your body has the ability to
transport ketone bodies to certain tissues and then use them for
energy, does not make it a normal process. It is an alternative pathway
that turns "on" only when your body is faced with depleted levels of
the main energy source, glucose.
Secondly, babies are not small adults. A baby's
liver and brain tissue are made up of different chemicals and pathways,
specifically geared to handle the high fat diet coming from mother's
milk. These pathways change as a baby grows and starts to eat other
foods. Eventually, the normal adult pathways are set up and the
infantile chemistry used as evidence to support the safety of ketosis,
stop working.
But this is not even related to the fact that
ketone bodies are toxic. In medicine, the three ketone bodies mentioned
above are classified as toxic acidic chemicals. At high levels, they
can cause your blood to become too acidic, a disease state called
ketoacidosis.
Granted, this is rare because most of the ketone
bodies will be used by the brain as an energy source. Ketoacidosis is
usually seen in type 1 diabetics. It is a medical emergency.
So, is ketosis dangerous to your body? Yes and no.
Yes, ketosis represents a state of starvation. Losing weight when the
body thinks you're starving is the best way to guarantee weight regain.
The weight will come back and come back as fat. No, ketosis will not
cause ketoacidosis in non-diabetics. And as long as you have a large
storage of fat, your brain will not starve for energy.
<h4>The Final Verdict</h4>
<ol><li>As an alternative physiologic
state, ketosis is not dangerous, assuming the levels of ketone bodies
do not increase to acidic levels.
<li>As a diet plan, ketogenic diets
are not recommended because of the state of starvation they create.
Your metabolism will eventually slow down setting you up for weight
regain in the near the future.
<li>Ketogenic diets, like the Atkins
Diet, may also be dangerous not because they cause ketosis, but because
they promote high protein and fat intake. High protein diets, unless
you're body building, increases urea production and can damage the
kidneys. Supporters claim that this just doesn't happen, reporting that
no kidney damage has occurred to the millions of dieters on Atkins Diet
or other ketogenic diets.
However, it is well known that microscopic damage
can occur to the kidneys effecting their ability to filter the blood.
But clinical signs of this damage may take several years to manifest.
Chronic renal insufficiency is a concern for ketogenic dieters, which
may cause problems in the years to
come.</li></ol>
<h4>Conclusion</h4>
Atkins Diet and other ketogenic diets (low Carb)
can be safe and effective in causing weight loss. However, I recommend
keeping ketosis to a minimum and keep your carbohydrate intake above 50
grams a day. Don't follow the suggestions for reaching an "induction"
phase. It's not necessary to turn "on" the alternative pathways
described above and burn fat.
Remember, healthy weight loss is to burn fat and
fat only. But it also involves keeping your rate of weight loss around
2-3 pounds/week. The induction phase promoted by the Atkins Diet can
result in a rate of weight loss far greater than 2-3 pounds/week. It
may sound good to you now, but how does gaining it all back as fat
sound? Because that will happen if you lose weight too fast.
For more information on ways to experience healthy
weight loss, visit
www.weight-loss-professional.com/articles
To Healthy Living!
Dr. Michael A. Smith
Chief Medical Consultant
Diet Basics Website
About the Author
Dr. Smith is the Chief Medical Consultant for Diet
Basics, a content based weight loss web site dedicated to all dieters
fighting to lose weight. Please visit his site at
www.weight-loss-professional.com/articles
Just one visit and you'll be hooked.