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.

The Low Carb-Ketosis Link

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...

1. Atkins Diet lowers glucose and insulin (the body's main energy source)
   
2. Alternative pathways are turned "on" to provide energy
   
3. One alternative pathway breaks down fat and produces ketone bodies
   
4. Ketone bodies represent the state called ketosis
   
5. The brain uses ketone bodies as an alternative source of energy

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...

Atkins Diet and Toxicity

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.

The Final Verdict

1. As an alternative physiologic state, ketosis is not dangerous, assuming the levels of ketone bodies do not increase to acidic levels.

2. 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.

3. 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.

Conclusion

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

Diet Basics.

To Healthy Living!

Dr. Michael A. Smith
Chief Medical Consultant
Diet Basics Website