"If Fructose is Bad, What About Fruit?"
If the fructose in sugar and high fructose corn syrup
has been considered "alcohol without the buzz",
in terms of the potential to inflict liver damage,
what about the source of natural fructose: fruit?
Only industrial, not fruit fructose intake
was associated with declining liver function.
Same thing with high blood pressure.
Fructose from added sugars was associated with hypertension;
fructose from natural fruits is not.
If you compare the effects of a diet restricting fructose
from both added sugars and fruit to one just restricting fructose from added sugars,
the diet that kept the fruit did better.
People lost more weight with the extra fruit present
than if all fructose was restricted across the board.
The deleterious effect of fructose was limited to industrial fructose,
meaning table sugar and high fructose corn syrup,
with no evidence for a negative effect of fructose in whole fruit.
This apparent inconsistency might be explained
by the positive effects of other nutrients (e.g.,fiber and antioxidants) in fresh fruit.
Well, let's find out.
If you have people drink a glass of water
with three tablespoons of table sugar in it,
which is like a can of soda,
this is the big spike in blood sugar you get within the first half hour.
Our body freaks out and releases so much insulin to drive down this spike
we actually overshoot and 90 minutes in
we’re relatively hypoglycemic, dropping our blood sugar
below where it was before we drank the sugar.
In response, our body dumps fat into our blood stream as if we’re starving,
because our blood sugars just dropped so suddenly below fasting levels.
Our body got worried.
What if you add blended berries in addition to the sugar, like a berry smoothie?
Now, they have sugars of their own, in fact in this experiment,
an additional tablespoon of sugar's worth,
so the blood sugar spike should be worse, right?
No, not only was there no additional blood sugar spike,
here’s the critical part, no hypoglycemic dip afterwards.
Blood sugar just went up and down without that overshoot,
and without the surge of fat into our blood.
This difference was attributed to the semisolid consistency of the berry meals,
which may have decreased the rate of stomach emptying
compared with just guzzling sugar water.
In addition, the soluble fiber in the berries has a gelling effect
in our intestines that slows the release of sugars.
To test to see if it was just the fiber, they repeated the experiment
with berry juice that had all the sugar but none of the fiber.
As you can see, there was a clear difference observed
early on in the blood sugar insulin responses.
At the 15 minute mark, the blood sugar spike was significantly reduced
by the berry meals but not by the juices.
But the rest of the beneficial response, like at 90 minutes,
were almost the same between the juice and the whole fruit,
suggesting that fiber may just be part of it.
It turns out there are fruit phytonutrients that inhibit
the transportation of sugars through the intestinal wall into our blood stream.
Phytonutrients in foods like apples and strawberries can block
some of the uptake of sugars by the cells lining our intestines.
So, adding berries can actually blunt the insulin spike from high glycemic foods.
Here’s what white bread does to our insulin levels within 2 hours after eating it.
Eat that same white bread with some berries, though,
and you’re able to blunt the spike.
So, even though you’ve effectively added more sugars, in the form of berries,
there’s less of an insulin spike,
which has a variety of potential short and long-term benefits.
So, if you’re gonna make pancakes,
make sure they’re blueberry pancakes.