Présentation de l’interview qui va suivre dans les jours qui viennent, et qu’il faut aussi que je traduise.
Stephen Phinney is an MD with a PhD in nutritional biochemistry who has been studying low-carb diets and their implications on the human metabolism for more than 30 years. He wrote two books with Jeff Volek, “The art and science of low-carbohydrate living” and “The art and science of low-carbohydrate performance” (and also a couple of other ones, including a science fiction novel “Above Evil”).
I read both of them and found them very interesting and inspirational. But although low carb seemed immediately obvious to me (after reading a couple of Jared Diamond books), nutritional ketosis (what?) always had a mysterious, scary vibe.
My mother’s face, my dietician friends or my fellow runners always expressed the same thing “are you nuts” ? Not to mention what you can find on the Internet.
But I may be a little nuts, and I like scary things …
To make the following posts easy to understand for all readers, here are a couple of quick definitions. Pardon me Dr Phinney, this is VERY reductionist 🙂
Our body needs energy to move and survive.
The energy comes from food (amazing, isn’t it ? I think sometimes we forget this).
In a very caricatured way, the food falls in 3 categories: carbohydrates (sugar and starches), proteins (meat, dairy/cheese, and some legumes) and fat (animal or vegetable);
The common dogma in the western industrial countries is that our energy should come from the three sources, with ratios such as 40 to 55% of energy coming from carbs, because carbs are “the fuel for your muscles and the only energy your brain can use”.
But… at the biochemical level, down deep in your cells, the mitochondria (organelles that provide energy to you cells) can use either carbs or fat as fuel to generate ATP, which is the actual source of energy for most of the organs. Then it becomes really complicated.
So, when there is no glucose available, fat is used. Or even protein.
Which means is it’s OK that people use low-carb diets (with typically less than 20% of the energy coming from carbs).
Even the brain, which requires close to 25% of the energy spent per day, still can function on mysterious substances called ketones, generated by the liver from fat when there is no carbs in sight.
The body generates ketones when you eat very little carbs for more than a day or two: it’s called nutritional ketosis.
Distance runners are obviously interested in the flexibility of human metabolic paths.
Every marathon runner knows that his carbs stores (glycogen) will be depleted before the end of the race. On the other hand, a very lean athlete (let’s say, me, with 7% body fat), has 5 kilos of fat stored, or 45.000 calories of energy reserve – when a marathon requires less than 5.000!
So … as a runner having switched to low carb a couple of years ago I wanted to know more about the subject, specially the nutritional ketosis and Stephen Phinney was nice enough to accept my request for a written interview, followed by a phone interview and in the upcoming posts you will be able to read the transcript of what we discussed.
As a fascinating bonus, he pointed me to this very, very interesting article in Science, that I commented in a former post, that shows that nutritional ketosis has very powerful positive effects on gene transcription and strong antioxidant properties, which is kind of a total scoop in the nutritional world : ketones are not only proper energy, but also influence our gene expression … for the best. As Stephen says “if it was a molecule that could be patented, it could be worth 100 billion dollars”. And it’s right there, inside your body – for free.
Stay tuned …