Biochemistry of the Atkins post Induction pause

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Doug Freyburger - 29 Jan 2004 22:16 GMT

http://www.lowcarb.org/josh_yelon/topic3.html

There are 3 listed studies. The first explains the
biochemical basis for the standard post-Induction pause,
the reason that most folks lose best near that CCLL not
at 20, why so many stall if they stay at 20, and hints
why folks who stay low over 6 months can fall out of
ketosis Eskimo-style.

> Serum T4 was not significantly affected during the VLCD.

This implies that low carbing is not bad for the thyriod.
The thyroid serves as a throttle, but it does not appear
to be harmed by low carbing if T4 levels are any indication.

> Although serum T3 decreased during the VLCD for both groups,
> the decrease occurred faster and to a greater magnitude in
> LC (34.6% mean decrease) than HC (17.9% mean decrease).

This shows that thyroid is *how* weight loss gets throttled
while low carbing. As the level of thyroid decreases, the
general metabolic rates goes down as well.

> Both groups exhibited similar progressive decreases in RMR
> during treatment (12.4% for LC and 20.8% for HC)

This explains why no matter what plan you follow, early loss
rates are higher than later loss rates.

> but values were not significantly lower than baseline until
> week 3 of the VLCD.

Bingo. This study has located the metabolic cause of the
standard post-Induction pause in week 3. *Extremely*
interesting. The initial loss during Induction is fast
because the body has not had time to become more efficient.
The sticks test dark early on then and then move towards
light in week 3 just as the study predicts.

> dietary carbohydrate content had an influence on the
> magnitude of fall in serum T3 ...

Folks, HERE is the CORE of why less is not more. Eat too
little carbs, and your thyroid turns down its output. Eat
enough carbs and the thyroid does not turn down its output.
This is why finding your CCLL works better for most than
staying low.

> RMR declined similarly for both dietary treatments.

Something similar happens to low fat folks, but the study
did not identify what it was.

Here is the entire text of the abstract.

The effect of varying carbohydrate content of a very-low-caloric diet
on resting metabolic rate and thyroid hormones.
Mathieson RA, Walberg JL, Gwazdauskas FC, Hinkle DE, Gregg JM
Metabolism 1986 May;35(5):394-398

Twelve obese women were studied to determine the effects of the
combination of an aerobic exercise program with either a high
carbohydrate (HC) very-low-caloric diet (VLCD) or a low carbohydrate
(LC) VLCD diet on resting metabolic rate (RMR), serum thyroxine (T4),
3,5,3'-triiodothyronine (T3), and 3,5,3'-triiodothyronine (rT3). The
response of these parameters was also examined when subjects switched
from the VLCD to a mixed hypocaloric diet. Following a maintenance
period, subjects consumed one of the two VLCDs for 28 days. In
addition, all subjects participated in thrice weekly submaximal
exercise sessions at 60% of maximal aerobic capacity. Following VLCD
treatments, participants consumed a 1,000 kcal mixed diet while
continuing the exercise program for one week. Measurements of RMR, T4,
T3, and rT3 were made weekly. Weight decreased significantly more for
LC than HC. Serum T4 was not significantly affected during the VLCD.
Although serum T3 decreased during the VLCD for both groups, the
decrease occurred faster and to a greater magnitude in LC (34.6% mean
decrease) than HC (17.9% mean decrease). Serum rT3 increased similarly
for each treatment by the first week of the VLCD. Serum T3 and rT3 of
both groups returned to baseline concentrations following one week of
the 1,000 kcal diet. Both groups exhibited similar progressive
decreases in RMR during treatment (12.4% for LC and 20.8% for HC), but
values were not significantly lower than baseline until week 3 of the
VLCD. Thus, although dietary carbohydrate content had an influence on
the magnitude of fall in serum T3, RMR declined similarly for both
dietary treatments.

Comments: they split 12 women into two groups of 6. Half were given a
1000-calorie low-carb diet, the other half a 1000-calorie high-carb
diet. The metabolic rate of the low-carbers declined by 12.4%, the
metabolic rate of the high-carbers declined by 20.8%.

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Hannah Gruen - 31 Jan 2004 13:46 GMT

>The first explains the
>biochemical basis for the standard post-Induction pause,

Probably not, although these are interesting studies. The
post-induction stall, or pause as you more accurately describe it,
likely has more to do with variance in water retention than changes in
fat burning rates.

Most people (but not all) go on induction and lose several or more
pounds of weight, all but a fraction of which represents water loss.
In fact, the fluid loss can be sufficiently extreme for some of us
that we will have some temporary issues with electrolytes, hence the
advice to use Lite Salt, take Ca/Mg supplements, etc. As time goes on,
our bodies adjust to the lower CHO intake and to ketosis and our fluid
retention also adjusts upward towards a more normal level. This can
mean that we re-gain a couple pounds of fluid. At the same time,
however, we are probably still losing fat. During that period where
we're regaining water weight but losing fat weight, we may see a
"stall" or "pause" on the scale, or even regain of a pound or two.
The fluid re-normalization is a one-time thing, so as fat burning
continues, eventually it will start to show up on the scale.

It is important to note that, as the study illustrates, extreme low
calorie dieting, of any kind, will probably result in slowing of your
metabolism, making weight loss slower and more difficult. Making some
effort to keep the calorie deficit smaller will help avoid that. 1,000
calories a day is far too few for most inactive women, even.

Also realize that fluctuations in water weight will continue to
obscure weight loss due to fat burning, on and off, throughout your
low carb dieting effort. For some reason these water weight ups and
downs seem to be quite pronounced in many low-carbers, and often lead
to a weight loss pattern that looks like several weeks of no loss or
even slight regain, followed by a "whoosh" of several pounds over a
day or three, followed by another pause, followed by another "whoosh",
etc.

HG

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