On Tue, 26 Feb 2002, Adrienne Smith wrote:

> Could you please clarify what you mean by "fruit sugar"?  I thought that
> the sugar present in fruit was fructose.  If this is incorrect, and fruit
> actually contains fructose, sucrose and glucose, then are there any food
> source that solely contain fructose??

See the table at
http://www.orst.edu/food-resource/sugar/com2.html  There do not
appear to be any fruits that contain just fructose.  I haven't
computed the fructose:glucose ratios, but just eyeballing the
list suggests that apples, pears, and watermelon are the best,
although apples and watermelon also have a liberal amount of
sucrose, which is half fructose and half glucose.

> I also thought it
> could replenish glycogen stores.  I simply tire out way too soon when
> working out after weeks of ultra low-carbing.  I am thinking of only eating
> fruit during a meal that also contains protein to blunt any insulin
> spikes.  Thoughts??

Since fruit does contain glucose, it can help to replenish
glycogen, but you'd have to eat more of it than you would have to
eat of a comparably dense starch, since the fructose won't help
(much) with that.

As for insulin spikes, consider this.  If your diet is generally
low-carb, then your glycogen stores are almost always low.  When
you eat glucose under these conditions, there should be virtually
*no* insulin spike.  This is because insulin is not involved in
the depositing of glucose into glycogen stores.  In short, your
liver and muscles will suck up that glucose very quickly, without
the help of insulin.  Carbs cause an insulin spike only when
glycogen stores are full.  In that case, there's no place for the
glucose to go, but it has to be pulled out of the blood, so it
must be converted to fat, and insulin is required for that.

This is why the CAD idea of a higher-carb "reward meal" that
doesn't trigger a big insulin response works.  By the time you
get to that meal, the glycogen tank is empty, or at least has
room for a liberal amount of glucose.  This is also why vigorous
exercise helps to improve "insulin sensitivity" -- it actually
depletes glycogen so that insulin has less work to do.

Furthermore, I believe (but I don't have any research on this)
that glycogen level is an independent determinant of appetite.
That is, when glycogen gets low enough, even though blood sugar
is normal, I get hungry.  This is why, like Richard Geller, I
seem to do much better with a sweet potato or some other starch
at dinner.  If I don't, I'm likely to binge later in the evening,
and whether it is a "paleo" binge or not, it's a problem.

Todd Moody
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