Fructose, in the long run, is nasty stuff. It is a non-essential molecule, and it doesn't matter what source it comes from, it is detrimental. It could be from a nice crisp Fuji apple or classic Coke; once absorbed into the blood stream it doesn't have a label such as "organic apple, I'm okay" it will just do its damage.

Another thing that Dr Lustig contends is very suspect in my mind. He claims that fiber, such as in whole fruits and vegetables, by slowing down absorption of sugars, makes them okay. A few minutes delay to even a couple of hours delay would be expected to make little difference in the number of molecules the body must deal with. And, even when phosphorylated on the first pass through the liver, fructose has become an active triose. There's a slight beneficial effect but it's unlikely to be major protectionprotective effect.

Fructose should really be eliminated from the diet to the greatest extent possible. I have done so for 8 years now, and the health benefits are amazing. I was, at age 60, in metabolic syndrome. On the very low fructose diet I lost 60 lbs, blood pressure went from 145/95 to 115/70, fasting blood glucose went from 95-65 mg/dl, LDL cholesterol dropped 80 mg/dl while HDL went up and triglycerides went down, too. All from simply keeping fructose below 4 g/day. These benefits happened in less than a year and I have maintained them for 8 years, "effortlessly" with no hunger, loss of energy or headaches; just better health. The mentioned effects are very well spelled out in Dr Lustig's lecture on hepatic fructose metabolism. Had that lecture been around I would have expected those effects, but my research was still in its beginning stages then and much of the information he presents has been discovered in the mean time. I was surprised at how it worked on so many criteria at the same time.

I finished transitioning onto a very low carb, limited protein, high fat diet the first of March and the benefits of that: a wonderful feeling of well-being and an increased level of steady energy are great.

Only simple sugars are absorbed into the blood stream: glucose, galactose and fructose. All are hexoses. Glucose is a universal sugar. Galactose is an animal sugar. Fructose is a plant sugar and we are poorly adapted to eat it as Dr Lustig points out in his video. Fructose, uniquely, has only 5 carbons in its inner ring structure while the other 2 have six carbons. That means fructose must be handled by different enzymes than glucose, and it turns out they are much the same ones used for alcohols, which we are also poorly adapted to eat. The adaptations we do have are probably the result of avoiding the relatively short term toxic effects we would get from eating spoiled fruit (alcohol) and the fruit sugars themselves. Fruits were, after all, a source of energy in the energy limited paleo world. They tended to come on mostly in the Fall when we needed to fatten for the rigors of winter and early spring. It was adaptive to fatten then. Now, when we have huge amounts of fructose all year round, it is causing serious diseases of civilization.

Dr Lustig also failed to mention other bad effects of fructose. It is roughly 10X more active than glucose at glycation formation, similar in glycation activity to galactose. Mother Nature seems to have selected the least damaging sugar for the basic fuel. Glycations, as they transform to AGEs (advanced glycation end products, produce ROS (reactive oxygen species) and many other nasties such as formaldehyde and beta-amyloid proteins (implicated in Alzheimer's). In fact, AGEs appear to be primary causes of autoimmune disorders including neuropathies, arthritis, macular degeneration and more. AGEs are directly involved in cataracts and other diseases. Fructose, because of its high glycation potential, can bond to DNA and can even split DNA thus it may be a teratogen and, through blockage of gene functionality, may be a cancer promoter.

Fructose, in the long run, is nasty stuff. It is a non-essential molecule, and it doesn't matter what source it comes from, it is detrimental. It could be a nice crisp Fuji apple or classic Coke; once absorbed into the blood stream it doesn't have a label such as "organic apple, okay" it will just do its damage.

Another thing that Dr Lustig contends is very suspect in my mind. He claims that fiber, by slowing down absorption of sugars, makes them okay. A few minutes delay to even a couple of hours delay would be expected to make little difference in the number of molecules the body must deal with. There's a slight beneficial effect but unlikely to be major protection.