OK, I've been curious about why, when people eat a small amount of high-carb foods the weight they gain is about 8 times the weight of what they ate. We all know that "matter can neither be created nor destroyed" and that the extra weight has to come from somewhere. We also all know that it takes about 3500 excess calories to gain just one pound, and there are not that many extra calories in the half pound or so of carbs that we eat. So what gives?

The answer is obviously water weight. But I had to understand how the water is retained. What is it about carbs that "sucks up" enough water to make us gain several pounds? So I"ve spent the morning searching technical web sites trying to figure out the answer.

My conclusions:
1) An increase of blood sugar from the carbs. Increased levels of sugar in the blood have an "osmotic effect" in which more water enters the blood (an increase in blood volume). Normally this would come from other tissues in the body, causing a mild dehydration, but as we are more likely to be drinking lots of water, the consumed water is used instead of cellular water. No dehydration, but increased blood/plasma volume, and an increase of weight.
2) Spiked insulin, from the increased blood glucose, stimulates the formation of glycogen in the liver. Increased concentration of glycogen in the hepatic (liver) cells. This would have a similar "osmotic effect" to the blood glucose, thus extra water accumulating in the hepatic tissues.

My unanswered questions:
1) Are these conclusions correct? (Any physiologists out there?)
2) If correct, I would think that after eating high carb foods, and keeping water consumption consistent, there would be less urine output. Does this happen? (Anyone out there experienced this?)

Just rambling thoughts on a Monday Morning.

Joan

Fascinating stuff, I'll be very interested in the responses too - thanks for digging all that up