Thursday, May 24, 2007

Metabolism and Ketosis

Dr. Michael Eades, co-author of Protein Power, recently made a very interesting blog entry on metabolism and ketosis. I highly recommend that if you are doing a low-carb diet that you read the original post ( I am very impressed by how quickly and thoroughly the Drs. Eades answer my questions.

I wrote the this comment:

May 24th, 2007 at 9:40 am

You said that the average person requires about 200 gr. of sugar. And that when the ketosis process is humming along the requirement for glucose drops to about 120-130 gm per day.

What is the reason for the drop in glucose requirements?

Can this help explain why many people doing low carb often lose 10-30 pounds per month the first few months then substantially less the subsequent months?

I am struggling to understand why weight loss seems more and more difficult the longer I am on a low-carb diet. I have lost 80 pounds over 9 months and am 20 pounds away from having 18% body fat. The first six months were pretty much by the book. At the end of the sixth month, I was losing at a rate of less than 5 pounds per month, 1/6 of what I experienced during the first month. There was a noticeable slow-down during the 3rd month. Any thoughts on why the slow-down?

His Reply:

Hi Daron–

It takes a while to become fully ketone adapted. At first, the body is making the ketones, but the tissues haven’t completely converted to using them for energy yet. The body then wastes the unused ketones (which are highly caloric) in the breath and urine. As time rolls on and the body becomes ketone adapted, it wrings every smidgen of energy it can out of the ketones, so you don’t get as great a loss as you do early on.

Second, as you lose weight, you decrease your metabolic rate. Resting metabolic rate is a function of weight more than anything else, and resting metabolic rate is the largest component of most people’s total metabolic rate. As you lose and the metabolic rate falls, it becomes more difficult to lose more. Sometimes it’s easier to think of weight loss in terms of percentage of body weight than in pounds. As you get smaller, you lose less, but even though you’re losing less, that less represents about the same percentage of your overall body weight as did the larger amounts you lost when you were larger.

The very best way to look at it is by percentage body fat. If you’re a male, then you should shoot for a body fat percentage of around 15-18% irrespective of what overall weight that represents. Which seems to be what you’re doing. Remember, you can decrease body fat percentage without losing any weight if you increase your muscle


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