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by dschleef 5168 days ago
Lustig's premise (from this and other sources) is essentially: (translated for a techie audience)

1. There is a clean pathway and dirty pathway for converting fructose to glycogen in the liver. The clean pathway is easily overloaded by consuming a lot of fructose at once. ("A lot" being more than 12 oz of soda, roughly.) The key bit is that the bad effects are non-linear.

2. The dirty pathway produces metabolites that cause the body's metabolism to switch to an imbalanced state, which if not corrected, leads to metabolic syndrome and type-II diabetes.

3. The dirty pathway is similar to alcohol consumption, with similar long-term effects. This is why he calls fructose a poison.

4. Dietary fiber slows down absorbtion of fructose, thus giving the liver more time to process fructose using the clean pathway. So an apple (fiber!) causes less of a fructose overload problem than a similar quantity of apple juice.

From this, Lustig hypothesises that metabolic syndrome is primarily caused by overconsumption of fructose, and that a diet that has low or zero fructose and high in fiber will correct metabolic syndrome. This is a testable hypothesis, and should be relatively easy to test, even by individuals.

My added notes:

1. There's lots of talk about "sugar", which is dumb, because "sugar" means different things to different people. Lustig means "fructose", which is present in sugar, HFCS, agave nectar, honey, all sweet fruits, fruit juices, etc.

2. Everyone's body, lifestyle, eating habits, exercise habits, and metabolic syndrome level is different, thus everyone will respond to fructose (and indeed any food) differently. If you care, learn how food works in your body and create a diet that fits your needs. And especially, don't extrapolate from your own experience to all people.

3. Several fad diets of recent years fit rather neatly into Lustig's recommendation, including Atkins, South Beach, mediterranean, raw vegan. If you care, find one that works for you.

1 comments

> should be relatively easy to test, even by individuals.

I did this. I cut my fructose consumption to the equivalent of two pieces of fruit a day and easily lost weight after years of struggling. My cholesterol fell from 255 to 160 mg/dl with an inprovement in the good/bad cholesterol ratios and a fall in triglycerides and uric acid. Also my inflammatory markers fell dramatically in some cases to unmeasurably low levels.

Lustig is spot on. A lot of people are heavily invested in the old orthodoxy and react accordingly. Fructose is a carbohydrate, but in any but small quantities it is metabolically a fat.

My wife and I did the same and she lost 40 pounds in nine months. I happen to notice that our appetite grew smaller during the period possibly explaining the weight loss. I have good data on this because we eat pancakes every sunday. I always cook the same amount since i use the whole buttermilk carton. Over time we went from eating 9 pancakes to eating 6 of the twelve I make. Also I cook 250g of pasta for us (including our two year old). We used to often eat it up. Now we always have leftovers. My daughters food intake has increased from one to two years old increasing the effect.
Can you tell me how you reduced your fructose consumption? What foods did you eliminate and what did you replace them with?
> Can you tell me how you reduced your fructose consumption? What foods did you eliminate and what did you replace them with?

Basically I stopped adding honey to my coffee (sad - it's delicious) and cut my fruit intake from 10-15 pieces to 2 per day. Also I eliminated all other sources of sugar such as cake, though these had been pretty minor in my case anyway.

I agree with Lustig that fruit is less toxic than concentrated sucrose or HFCS, but I am living proof that in sufficient quantities it is still bad news.

I added some extra fats (nuts, flax oil) and some extra protein (beans, peas, fish, red meat, chicken).

The best thing about the weight loss is that I lost weight in the bad places (ie my stomach) which previously had been impossible to move.