What’s Our Preferred Fuel?

Dr. Jay Wortman has been thinking about whether our bodies prefer to run on carbohydrates (as a source of glucose) or, instead, on fats.  The standard American diet provides derives about half of its energy from carbs, 35% from fats, and 15% from proteins.  So you might guess our bodies prefer carbohydrates as a fuel source.  Dr. Wortman writes:

Now, consider the possibility that we weren’t meant to burn glucose at all as a primary fuel. Consider the possibility that fat was meant to be our primary fuel. In my current state of dietary practice, I am burning fat as my main source of energy. My liver is converting some of it to ketones which are needed to fuel the majority of my brain cells. A small fraction of the brain cells, around 15%, need glucose along with a few other tissues like the renal cortex, the lens of the eye, red blood cells and sperm.Their needs are met by glucose that my liver produces from proteins. The rest of my energy needs are met with fatty acids and these come from the fats I eat.

Dr. Wortman, who has type 2 diabetes,  in the same long post also writes about oolichan grease (from fish), an ancestral food of Canandian west coast First Nations people. 

Steve Parker, M.D.


Filed under Carbohydrate, Fat in Diet, Fish

4 responses to “What’s Our Preferred Fuel?

  1. Philip Thackray

    I’ll read the article just to stroke my conformational bias! But I don’t need any more convincing. I’m about 8 years into low carb high (SATURATED!) fat and it is a wonderful life style. (I’m not diabetic but I did/do have a dramatic hypo-glycemic reaction following consumption of carbohydrates. So carbs are not an option for me.)

    It is too bad that every piece of dietary advice from Big Government, Big Medicine and Big Business is exactly the opposite of Dr Wortman’s.

    • Steven

      Your inability to tolerate carbohydrate is rather disconcerting… It is my understanding that metabolic flexibility is a rather important attribute. But maybe I’m jumping the gun, maybe you are just referring to a hypoglycemic reaction upon first adding carbs to a lower carb diet–without time to adapt..

  2. Philip Thackray

    Dr. Parker,

    Good reference, my conformational bias is greatly satiated!

    Phinney and Volek talk about the oolichan grease in their recent book. I followed some links to a paper that details the contents of the oolichan grease. In the abstract, the author states that the oolichan grease has a different lipid profile than the oolichan fish fat itself. The process of making the grease may be important to the nutritive value of the grease.



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