Dr. Robert Lustig lectures on the perils of sugar, Fructose in particular.
He talks about how obesity has risen at the same time as fat
consumption has decreased, how soft drinks and the invention of
High-Fructose Corn Syrup are two of the larger culprits and the
biochemistry of Fructose.
Below I have summed up the lecture in plain English, simplifying
facts and eliminating scientific terms. Towards the end I sum up a few
points from a rebuttal and end with my own opinion of the lecture.
Cliffnotes:
* We are eating more calories than before. This wouldn’t happen if
the brain were suppressing your appetite properly. The suppressor is
being circumvented.
* Coca Cola uses sugar to hide how much salt it contains. The salt is
there to make you thirsty again. (I have been unable to confirm that
Coke contains any salt)
* All countries that have adopted the US diet are having the same problems with obesity, heart disease and diabetes.
* Up to 30% of Fructose is metabolized into fat. A low-fat high-Fructose diet isn’t really low-fat.
* Fat consumption has reduced by25% in the last three decades. At the same time obesity has increased.
Summary of the movie:
Obesity:
We all weigh 25 pounds more than we did 30 years ago because we eat more calories.
Obesity is a problem for children down to 6 months old.
There is a mechanism in the body that is supposed to tell you when you
are full. The only way to eat more than you should is to suppress this
mechanism.
The extra calories we are eating come from carbohydrates like sugar and
not fat. (Note that the speaker uses figures for 1-17 year olds to
demonstrate this point and that this does not hold for adults where
calorie consumption has increased across the board)
All countries that have adopted the US diet have this same problem.
Soft Drinks:
In the last three decades fat consumption has decreased 25% and yet
obesity has increased. During this time there has been a 41% increase in
the consumption of soft drinks.
Coke uses sugar cleverly to disguise all the salt they put in it to make
sure you get thirsty again very shortly. The caffeine augments this
effect as it makes you pee. (Note that I have been completely unable to
confirm that Coke contains any salt at all, it does contain high
quantities of sodium, which usually indicates salt, but this may also be
because of the preservatives they use)
Consumption of soft drinks has been shown to increase odds of obesity and type-2 diabetes.
High Fructose Corn Syrop:
High-Fructose Corn Syrop (Glucose-Fructose
in Canada, Isoglucose in Europe) is an extremely common replacement for
white sugar (Sucrose). It is made from corn and contains about 55%
Fructose and 45% Glucose, while Sucrose contains exactly 50% of each.
HFCS is sweeter than Sucrose, by ca. 20%. It is also cheaper to make,
which is why it is extremely popular in food production. The average
American eats 63 pounds (30kg) of it each year.
The speaker asserts that HFCS is no worse for you than any other source of sugar. (This is highly debated)
Fiber:
Fiber has
dramatically reduced in our diet in the last few centuries. The caveman
got 100-300 grams of fiber each day but we get around 12. The reason is
that food with a lot of fiber is slow to cook and doesn’t store well.
Fast food invariably has less than 1g of fiber per serving.
Glucose:
When Glucose enters the body, most of it is used up by
cells and organs before it reaches the liver. What does enter the liver
is easily stored there as Glycogen. When this happens the liver releases
chemicals to signal to the brain that it should stop eating.
Fructose:
When Fructose enters the body, all of it reaches the liver where 30% of
it gets turned into fat. Harmful chemicals are generated in the process.
These chemicals can cause Gout and Hypertension, increase
blood-pressure and suppress the signal to the brain that you should stop
eating. (This part is hugely simplified. In the talk this is a long
drawn-out discussion about the biochemistry of metabolizing Fructose)
Fructose metabolized in much the same way as alcohol, only it doesn’t affect the brain directly.
What to do to counteract obesity:
1. Stop consumption of all sugary drinks, including juices.
2. Always eat carbs with fiber. Fiber counteracts many of the negative aspects of Fructose and makes you feel full faster.
3. Wait 20 minutes before second portions.
4. Buy TV or computer time minute-for-minute with physical activity.
(this doesn’t necessarily mean high-intensity exercise but can merely
be doing the dishes, walking from work etc)
Exercise:
Exercise isn’t
really about burning calories. It makes it easier for the body to tell
you when to stop eating and helps it regulate blood sugars. It reduces
stress and therefore appetite and it speeds up the metabolism, burning
off chemicals before they get turned into fat.
Final Points
The earlier you expose children to sweets, the more they will crave
sugar later in life. This also goes for pregnant women and their unborn
babies.
So why doesn’t the FDA regulate Fructose if it is this harmful?
Apparently they only regulate toxins that have a harmful effect in a
single dose, not those that need chronic exposure. So sugar is excluded.
Rebuttal:
Some points of criticism have already been included inline in parenthesis but additional points from “The bitter truth about fructose alarmism”, a rebuttal to the lecture, are included below.
One of Lustig’s main points is that when Fructose is consumed it does
not send a signal to the brain to stop eating. However, when one eats
anything sugared, the Fructose is always accompanied by (nearly) as much
Glucose which DOES send such a signal to the brain.
Most of the effects Lustig claims Fructose has on appetite has only
been shown in studies where Fructose was 30% or more of total calorie
consumption, which is unreasonably high.
Like the effects of Ethanol, the effects of Fructose are doze-dependent.
http://froztwolf.com/2010/05/sugar-the-bitter-truth-review-and-summary/
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Sugar: The Bitter Truth
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