On Wed, 31 May 2000, Amadeus Schmidt wrote:

> My question:
> Does glucagon *reduce* insulin, anyway?
> I think they only work against each other?

Glucagon does not reduce insulin, but its effects are opposed to
those of insulin.  Hormonally, glucagon is anti-insulin.

> and:
> Can (high, any, whatever) protein in a meal reduce it's insulin peak?
> I didn't find any reference for this claim.

No.  Since protein does not reduce insulin it cannot reduce the
insulin peak of a meal.  But since protein stimulates only about
40% as much insulin secretion as carbohydrate, *replacing* carbs
with protein will tend to reduce the insulin peak, given equal
calories.  That is, a 500 kcal high-protein meal should generate
a smaller insulin response than a 500 kcal high-carb meal.

> Can anybody mention a reference or study, why or how or when
> protein can decrease insulin levels if protein is *added* to a meal?

I don't think there is any such study, because protein can't do
this.

> These question seem to be essential for the zone diet- aren't they?

There is also the fact that if one consumes more protein at one
time than the body can assimilate, the insulin response will be
comparable to that for carbs, because the protein must be
converted to fat for storage, and insulin is needed for this.
Sears says this ceiling is about 35g of protein, but this is
controversial.

> What i found to be inconsistent in the theory:
> Many small meals or snacks per day are recommended, each including
> carbohydrate foods. But insulin goes up for a certain time after a meal
> only. So with many meals or snacks you won't let the insulin ever
> come back to normal - exept at nicht when sleeping.
> Wouldn't it be much better to have few meals only, so there would be
> only few insulin peaks over the 24 hours?

The Zone requires three moderate (by some standards, small)
meals, after which one should *eat nothing at all for 4 hours.*
This supposedly allows insulin and glucagon levels to return to
baseline.  The timing of snacks depends on your daily routine.
If you have lunch at noon but don't have dinner until six or so,
then you have a snack at about four.  Then, assuming that you go
to bed about 4 hours after dinner, you have another snack at
bedtime.

> Can protein reduce insulin?

No.  One point that Sears doesn't mention (I think) is that the
glucagon response to protein depends to some extent on its amino
acid composition, with arginine being a more potent glucagon
stimulator.

Also, the insulin peak occurs earlier than the glucagon peak.  If
you eat a Zone meal, your insulin should peak about 1.5 hours
later, but the glucagon peak occurs about 2.5 to 3 hours later.
This is why you don't want to eat for four hours after the meal,
because eating almost anything will probably inhibit the glucagon
response (pure fat might be okay).

Of course, all this depends on other factors as well, such as
exercise patterns, stress, and one's degree of insulin
resistance.  In a highly insulin resistant person, it will
probably take much longer for insulin to return to baseline, thus
preventing the glucagon from being as effective as it should be.

Todd Moody
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