Thread: Why do I lose weight when I take time off?

That is not uncommon. You lost muscle.

Use it or lose it, that simple really.

There is no reason for the human body to keep unnecessary muscle (it's an efficient machine), so it gets rid of it.

Originally posted by Jodi
You lost muscle.

20 lbs of it? Wow!
So my body is naturally at 170 lbs. I'm 6 feet. That can't be good.
:o

i think there is something like 100grams of protein per pound of muscle- correct me if i'm wrong= the rest is water weight that goes along with increased glycogen capacity.

Stop working out- you'll lose some muscle and storing capacity, but the water is where the weight came from so rapidly- I've read that water weight can fluctuate by as much as 7lbs in a day.

As the others stated, you are losing muscle. Would happen to anyone. Some people may maintain more muscle, others less due to various factors including, metabolism and genetics. I had a friend of mine that within 2 weeks of not working it was noticeable that he was losing muscle.

As Hanz pointed out, you lost mostly water. With training, the body stores more glycogen in the muscles to allow for it to be quickly used for energy. With each molecule of glycogen, 3 molecules of water are stored. Once you stop training, your body does not need these stores and dumps them.

Here is some info taken from

http://www.personal.psu.edu/staff/t/a/tam275/Fuel.html



In a study with rats, Ren et al (6) observed that the glucose transport protein, GLUT4, had an approximately two-fold increase in expression following training and that this increase was roughly propotional to glucose transport activity. With humans, McCoy et al (3) showed that when fed adequate amounts of carbohydrates post-exercise, their glycogen storage was directly related to GLUT4 protein content. Phillips et al (5) was able to demonstrate that increases in GLUT4 were indicated as an early response to endurance training in humans and that progressively longer durations of training resulted in further increases in GLUT4. Recently, these results were observed more completely in rats,where 5 wks of endurance training resulted in significantly higher levels of glycogen accumulation and glycogen concentrations, relative to untrained rats, and these increases corresponded with approximately 50% increases in muscle GLUT4 protein (4). Hickner et al (8) extended these findings to humans by observing that muscle glycogen concentration 48/72 h following carbohydrate feedings post-exercise were signigicantly higher in trained subjects and that glycogen accumulation correlated with muscle GLUT4 content. Together, these results indicate that glycogen accumulation is directly associated with GLUT4 levels and that GLUT4 expression, and thus glycogen storage, can be increased with training. Additionally, an early training response which likely contributes to overall glycogen storage is the increase in muscle hexokinase activity following exercise (5,6).

Here is another link, look under muscular endurance.

http://www.dinc.com/maf/1998/nl_05_03.htm