Found this on lowcarbfriends:
"From tracking a lot of people who become assimilated into the lowcarb lifestyle (hehe...resistance is futile!) a pattern emerges....
the 2 week induction is pretty heady...weight lost just about every
single day, enormous and unbelievable amounts of weight loss are reported.
This is often followed by complaints that weight loss "stalls" or that
the rate drops to only 1 pound per week. (if that).
Many people just don't know that fat-loss ...the actual goal when on a
weight-reduction" diet, is rate-limited. In other words, the human
body has factors that prevent more than a certain amount of fatty-acid
release from storage...and even more factors that prevent those released fatty acids from being used up instead of stored back into the fat cells.
A priority of the human body is survival. Anything that threatens its
survival results in the cascade of events to maintain the previous
status quo. Water fluctuations are one way the body does this.
OK...so you done good on Atkins' during induction...lost 10 pounds the
first 2 weeks.
Maybe 7 the first week and 3 the second. But, whoa!
Weeks 3 and 4 there is NO loss! And weeks 5 and 6 is only 1/2 pound
each! So... what gives?
Initially, the body jettisons the water attached to the glycogen stores
that we diligently deplete to get into ketosis...this accounts for
about 3-5 pounds of water.
In addition, muscle stores of glycogen are not
being replaced when used...which will account for the rest. All in
all...MAYBE 1/2 pound of fat was metabolized during the first week... and MAYBE 1/2 pound of fat was metabolized the 2nd week. Of that 10
initial pounds, only 1 pound was fat and 9 pounds water...
The body senses this lack and sirens start shrieking:
Warning! Warning! Losing water... new thing...got to get back to the
status quo! Brain tells body to produce and release that vasopressin
antidiuretic hormone....more water is retained, and no weight loss
noticed.
Fat loss is still occuring, MAYBE even 2 pounds per week, because
ketosis is firmly established and appetite supression is in
effect...but water retention is hiding that continuing fat loss.
The body is preventing dehydration with this mechanism, and that's a good thing.
From the perspective of the scale, it can be discouraging.
Which is why the mantra: Water retention masks fat loss (repeated
frequently to oneself ) is helpful.
Water retention will mask ongoing fat-loss for as long as the body
retains the water. We can combat this by drinking more water...but we
aren't going to totally overcome this mechanism during the initial
water-loss phase of the Atkins diet.
By weeks 5 and 6, things start to get back in balance, and the scale
will begin to reflect the true fat-loss...which, as mentioned before is
rate-limited.
Individuals vary, but max weight loss runs about 2 pounds per
week...under extremely optimal conditions... or 1% of body weight.(whichever is the lower number)
Take-home message: Even when the scale is in a stall, fat loss can be
occuring. Don't use the scale as an excuse to undermine your progress
Hope this can shed some light for you as well!"