Lustig fructose 

"Lustig" is German for "funny" or "amusing".  Usually Ashkenazi  when used as a surname

Robert Lustig is an attention-seeking food-fanatic and seems to be some kind of nut.  But a small recent study suggests that he may be on to something.

His extreme claims about natural fruit sugar (fructose) being a "poison" have rightly put most of the medical research fraternity against him and the research evidence  against his demonization of fructose is strong.  There are even some studies (e.g. here) that suggest that fructose is good for you.

He does seem to have crumpled under the weight of opposition  and now demonizes sugar generally, including ordinary table sugar, which is a combination of fructose and glucose.  And, broadly speaking, his argument that in some way we get used to a high sugar intake and thus consume more sugar that we otherwise would is reasonable enough.  Habituation is a well-known process in many things.  I reproduce below some comments on his latest book.

But has he given up too soon?  A recent study does show a strong differential response to fructose versus glucose.  Admittedly the study is small and very short term but it is carefully constructed, cautiously analysed and relies on direct brain measurements rather than subjective judgments.

On the other hand (you almost need to be an octopus in this matter) measuring cerebral blood flow is a pretty crude measurement of anything -- but on yet another hand several different measures produced similar results

What I think the latest results suggest is that there needs to be more attention to glucose.  Fructose may not be the villain but glucose may be the saviour!  Lustig may have been right in separating out different types of sugar, even if he originally focused on the wrong one.  Should we replace ordinary table sugar with glucose only?

Glucose is not as sweet as table sugar so we would have to use more of it  -- which might not be good.  But we could add a bit of aspartame for more sweetness.  Yes:  I know the cannonade of condemnation that will greet me from the aspartame freaks.  Been there.  Done that.

Excerpt:

Waistband feeling a bit tighter, or buttons straining after Christmas?

While it’s easy to blame your appalling willpower or TV-inspired lethargy, according to a respected U.S. obesity expert, weight gain might not be your fault at all.

In a fascinating new book, Robert Lustig, a professor of clinical paediatrics at the University of California, expounds a whole new scientific theory.

He argues that the urge to overeat and lounge around doing nothing is not a sign of weakness.

It is, he says, a hormonal issue, triggered by eating too much sugar.

He points the finger of blame at the hormone leptin, which acts like an appetite thermostat.

As one of two ‘hunger hormones’ in the body, leptin works to decrease the appetite (its partner, ghrelin, increases appetite).

When you have had enough to eat, your fat cells release leptin, which effectively dulls the appetite by instructing the brain that it’s time to stop eating.

But Professor Lustig warns that our sweet tooth is sending this process haywire.

For many years scientists thought obesity could be caused by a shortage of leptin — thinking that without adequate levels, overweight people simply never received the message that they were full.

But more recent studies have shown that obese people have plenty of leptin (in fact, the fatter you are, the more of it you appear to have), but are more likely to be ‘leptin-resistant’.

This means the cells in the brain that should register leptin no longer ‘read’ the signals saying the body is full, but instead assume it is starving — no matter how much food you continue to eat.

In panic, the brain pumps out instructions to increase energy storage — instigating powerful cravings for high-fat, high-sugar foods because these are the easiest and most immediate forms of energy — and conserve energy usage, by dampening any urge to get up off the sofa and go for a run.

The food cravings are made even more intense — and impossible to resist — because leptin is supposed to dampen the feeling of pleasure and enjoyment you get from food by suppressing the release of the brain chemical dopamine, helping to decrease appetite.

But if you are leptin-resistant, food never stops tasting delicious, no matter how much of it you eat.

This, says Professor Lustig, is why many overweight people find it so hard to stop eating, and why diets so often fail.

Scientists have been struggling to work out what causes leptin resistance.

But now Professor Lustig and his team have been able to show — in repeated studies on humans — that too much sugar in the diet is to blame.

High sugar diets lead to spikes in the hormone.  This is needed to clear sugar out of the blood and into storage as fat.

But repeated insulin spikes, due to a high sugar diet, can lead to a condition called ‘insulin resistance’ (when the cells have been so bombarded by insulin they no longer respond to it).

Professor Lustig believes insulin resistance triggers leptin resistance, and, crucially, he has discovered that by reducing insulin levels it is possible to improve ‘leptin signalling’ (the brain’s ability to read leptin), stop cravings, put the brakes on food consumption — and trigger weight loss.

In his new book Fat Chance, Professor Lustig explains that leptin resistance — and sugar — is at the root of the obesity epidemic.

More here


Posted by John J. Ray (M.A.; Ph.D.).