A few weeks ago my wife wanted to take a long, long car ride to a Japanese grocery store maybe 50 miles away. As this was my wif’e’s idea and I already drive too far because of my commute, she offered to drive as part of our negotiated settlement for me going. I brought my Kindle and read ‘The Art and Science of Low Carbohydrate Lving‘ – or rather struggled to read. This is the second time. I am going real slow, as this book is by 2 researchers and written more for their colleagues than dopes like me.
Something that blew my mind was right there, in the text, it explained why a few months back as an experiment, I was able to eat phenomenal amounts of butter and not gain weight. I wasn’t losing – but I could add 1,000 calories a day and not gain weight. I didn’t understand why until I read this passage:
Medium-chain fatty acids are found in dairy fats (milk, butter and cream) and in some ‘tropical oils’ like palm oil. These fatty acids, with the slight exception of 12-carbon laurate, are not incorporated into triglycerides and stored in the body. Once eaten, they must be promptly oxidized for fuel by mitochondria. Unlike long-chain fatty acids that require assistance from mitochondrial membrane proteins to get into the mitochondrial matrix, medium-chain fatty acids bypass this regulatory step. If we consume more medium-chain fats than can be burned in a short period of time, our liver converts the excess into ketones, which in turn can be burned by a wider range of organs (e.g., the brain).
Oh, God – I LOVE reading stuff like this…NOT! I end up reading it out loud, my wife wondering what the Hell I am mumbling about. My simplified, de-doctorfied translation of the above is as follows:
Medium-chain fatty acids are a type of fat found in dairy fats (milk, butter and cream) and in some ‘tropical oils’ like palm oil. These types of fats, with one exception, can’t be stored as fat. Once eaten, they get turned into fuel straight away and used by the organs that can use this stuff straight Not all organs can, however, and any leftover gets turned into ketones and can then be used by more fussy organs. If there’s any remaining after that, they can be excreted, which helps turn your ketosticks dark red.
It is also interesting to note as an aside that different organs have different fuel needs. The brain CAN run on ketones for the most part, but does need some glucose – which can be created by the liver as needed. This is why you need the right amount of protein in a very low carb diet: your body can make the glucose it needs from the protein. Too much protein, however, and you might make too much glucose if your body is predisposed to this sort of thing.
So anyway, I’ve convinced myself I can eat all the butter I want and not get fat. That’s awesome – unless I’m totally wrong however.
My one question, which I could not find the answer for in the book, is this: what does the body DO with the extra ketones it doesn’t burn? While you do excrete some in your urine, it can’t account for me eating an extra stick of butter. If it doesn’t get turned to fat and doesn’t get burned, what is the mechanism for the body disposing of it?
Low Carb Confidential 
Hmmm interesting. I’ve got to get that book. I think you explained that well 🙂
“My one question, which I could not find the answer for in the book, is this: what does the body DO with the extra ketones it doesn’t burn? While you do excrete some in your urine, it can’t account for me eating an extra stick of butter. If it doesn’t get turned to fat and doesn’t get burned, what is the mechanism for the body disposing of it?”
I’ve been consuming between two and three pounds of butter a week for at least three decades. Most of the time I’ve weighed around 165 pounds. More recently my weight crept up to 185 and I had to buy trousers one or two inches larger in waist measurement. Wanting to lose the fat around my middle, I tried eating less food – mostly less bread. My weight didn’t budge until I stopped dipping into the mixed nuts jar. (Gotta watch out for those omega-6s) Now I’m down to 170 and can wear my normal waist size again. Increased physical activity may have had something to do with it. I was extraordinary busy this Summer with gardening.
For many years I’ve suspected that there are various limitations on the amount of calories one can absorb as food passes through the digestive tract. I’ve written extensively about these matters and my thoughts on the matter can be accessed if you Google “David Brown Calorie Excretion” and “David Brown Unabsorbed Calories.”
May I so rudely suggest…poop?