Tuesday, May 17, 2011

The Difference between Ketosis and Ketoacidosis

I was talking to the mother of a type 1 diabetic eight year old last week.  She closely monitors her daughter's insulin and usually injects her seven times a day.   I don't know the mom very well, and she has no idea I'm writing this blog.  I'm also not an expert on diabetes, so I didn't want to suggest that I might know something better than she does.  In general, my experience has been that parents of diabetic children are pretty knowledgeable, so the last thing I wanted to do was to come across as preachy in an area that's not my area of expertise.

So we talked in general about the practical difficulties of living with diabetes.  At one point the subject turned to carb counting, which she told me they do at every meal.  I asked whether life would be any easier for them if they eliminated or severely restricted the carbohydrates in their diet.

"Oh, no," the mom quickly assured me, "We couldn't do that.  It would lead to keto-what's it called?"

I left it at that.

But it reminded me that there is general confusion between the terms ketosis and ketoacidosis.

Let's start with ketoacidosis:  This is well-described in the medical literature, and there is an excellent description in the Merck Online Medical Library.

In layman's English, ketoacidosis is the potentially life-threatening situation that occurs when diabetics (usually type 1) cannot metabolize the sugars in their bloodstream because their pancreas isn't producing insulin.  This might typically happen when a patient is unaware that they are diabetic, or when they don't properly control their insulin for one reason or another.

A number of metabolic processes are set in motion, one of them being hyperglycemia (essentially the opposite of low blood sugar, or hypoglycemia).  Remember that insulin's role in the body is to regulate blood sugar levels to ensure the right amount of glucose gets to the brain and tissues, while storing excess energy in the fat cells for when it might be needed.

So with ketoacidosis, the body reacts to the large amount of unregulated blood sugar by going into what is essentially metabolic overdrive.  It starts metabolizing large amounts of fatty acids and proteins, ostensibly to produce the glucose the body needs to stay alive.  This in turn results in the creation of acids as a byproduct, and they are excreted in the urine in the form of ketones.   However, the body is in a crisis situation in which its getting the wrong amounts of the nutrients it needs, and can result in the patient being really hungry, needing to pee a lot, feelings of nausea and headaches.  In the worst cases, loss of consciousness can result.

Let's switch to ketosis, which is not life-threatening, and which results in the excretion of significantly fewer ketones.  According to Gary Taubes, the difference is ten- to forty-fold.

When you eat very little or no carbohydrate, the body switches to burning fat and muscle to satisfy its internal energy needs.  This is a clever adaptation to ensure we don't starve easily in times of famine.

You could compare this to a widget-producing machine that switches from oil to coal when the price of oil goes up, allowing production levels to stay the same.

Ketosis is fundamentally very different from ketoacidosis, because while in both cases fat and muscle are burned and the by-product is ketones in the urine, with ketosis the metabolic process is a normal one, not one that is caused by an underlying internal crisis.

The way I see it, whether you are on a standard weight-loss diet or whether you restrict your carbohydrates, the only way to burn fat is by putting your body into ketosis.  The difference is only one of degree.

To use the machine analogy again, an alternative way to confront higher oil prices could be to economize by using less oil, though this would likely result in the production of fewer widgets, just as a standard weight loss diet often results in an across the board reduction of nutrient intake.

So to get back to the story of the mom of the diabetic eight year old, it seems to me that she was confusing the two terms. 

I don't understand why on earth restricting her daughter's carbohydrates would result in ketoacidosis.  If anything, it would be the opposite.  In fact, this is why diabetics need to monitor their blood sugar very closely if they decide to reduce their carb intake - not because they might go into ketoacidosis, but because their regular medication might be too strong for their lower blood sugar levels.

The only reason I can possibly think of why a parent might be hesitant to eliminate carbohydrates in a diabetic child would be if the child was already on the thin side.

In poorer nations than ours, where more children don't get enough food to eat, this probably wouldn't be an issue.  Here, where a large percentage of children are chubby, a parent might be concerned about the prospect of their child being skinnier than the rest.

Having said that, I don't believe that being lean, in and of itself, is a bad thing.

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