"...So the sugar, once you start absorbing the sugar, it will over time, reduce your mitochondria so, mitochondria, our body is made up of cells, and we have millions and millions of cells that constitute our body. And each cell has a nucleus, which is kind of brain of the cell, but each cell also contains little units called mitochondria. These mitochondria are what produce energy.Mitochondria are more like turbine engines than batteries (which only store energy), but that's quibbling.
"SHELLEY: Are they like batteries? Our EverReady battery inside the cell?
"RICHARD JOHNSON: They are like our batteries. They’re basically the energy factories of the cell, and they produce the energy that runs our cells. When you produce a lot of energy, that it is important in being able run, and to bicycle, and to climb mountains, and to swim and stay up. The energy we produce is very important, and that energy is called ATP. When a person eats more food, generally they will produce more energy. But with fructose, when you eat more, it actually slows the production of the energy, so it has an opposite effect. So you produce less energy, and you accumulate more fat, and when you produce less energy, you tend to be more tired. Now what happens over time — the more sugar you eat, it actually seems to cause damage to the mitochondria. Over time, you may actually lose mitochondria. At that point, you are almost locked into a lower energy state. Unless you can stimulate the growth of more mitochondria to allow you to get back to your original energy level.
"SHELLEY: You mean that once a child or a grownup’s body is in trouble, metabolically, then eating more sugar will help them feel more energetic for a few minutes or perhaps an hour or so. But in the long run, eating that sugar might be killing more of the batteries inside of their cells?
"RICHARD JOHNSON: Yes. Basically over time, you start to lose these mitochondria. Now in children who become obese, most of them still are have quite a few mitochondria, so they can recover quicker. You can get them back to normal weight easier than you can a 55-year-old or 60 year old, who may have lost quite a few mitochondria. It’s going to be harder to get that person back to a low stable weight, unless you find ways to stimulate their mitochondria to increase their numbers. The very best way is exercise."
A more substantive difference is that I don't think it's fructose which causes mitochondrial death, but glucose. From what I've read, unless your're a spermatazoa, you're not using much in the way of fructose as a fuel source.
While this study states that a "High-fructose diet, an animal model of insulin resistance, causes mitochondrial dysfunction by altering the activity of respiratory chain complex I." this one doesn't find direct effects from fructose, and was looking for them. I suspect that since complex I uses glucose as a fuel source, and fructose is metabolized into fat, having complex I down-regulated is a logical consequence.
But, if you eat lots of fructose in the Modern American Diet, you're also eating lots of glucose since sugar is 50% glucose and 50% fructose; and that we eat too much sugar is the point of Dr. Johnson's book.
I've come to the conclusion that Dr. Johnson states here from my own reading, and have been pursuing a strategy to promote mitochondrial growth for a while now. Seems to work well, as my race time are improving, the races are getting easier, and I feel better at the end. I also find my cold tolerance has improved markedly over the summer, which is a first. I've been skiing and motorcycling and I feel much, much warmer in sub-freezing temperatures than I remember from last year.
I've not read Dr. Johnson's book, but I have read one with a detailed program on how to promote mitochondrial growth, if you're interested. It's Dr. Maffetone's Big Book of Endurance Training and Racing. I suspect diligent walking for longer periods will also work (if you don't like running), which is why Seth Roberts has seen the results he has.