"Glycogen losses or gains are reported (2) to be associated with an additional three to four parts water, so that as much as 5 kg weight change might not be associated with any fat loss."Post moved to Substack.
Monday, April 7, 2014
Glycogen and Water Weight
One regularly hears that when one goes on a low-carb diet, one loses glycogen, and the weight loss is due to the fact that glycogen is stored with water, so the weight one loses is due to the water lost with the glycogen.
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Water weight and glycogen stores seem highly related on a personal level. There was a time when I tried 45 hour fasts and I'd watch my weight drop near 10 lbs over that period. Sure, maybe 1-2 lbs (tops) of that weight loss was bulk, but given that my max caloric burn over that time would be about 4K calories, you just can't get to the 10 lb figure without a lot of _something_ else being lost.
ReplyDeleteThis also explains why after a carb bender my weight goes way up (and I look bloated).
It's more anecdotal observation, but bodybuilders seem well aware of the correlation between carb refeeds and water retention. Hard to imagine there's not _something_ at play with carbohydrates and water.
I've lost 10 lbs on a Maffetone-method run that is designed *not* to deplete glycogen.
ReplyDeleteIt turns out that there's a good bit of evidence in the literature that ingesting glucose does cause the body to dump fluid into the gut to buffer it.
Maybe, if I've got some time, I'll post it. :)
I'd also be interested if there's any evidence to the contrary. So far the only research that was supposedly to the contrary was a link to the first study above.
Whoops... ;)
Justin, answer to your question, it appears that the body also buffers glucose in the blood:
ReplyDelete"Infusion of hypertonic glucose during dialysis results in a greater increase in relative blood volume (RBV) than equal volumes of other solutions. As mannitol has the same osmolarity, molecule mass and charge, the greater increase in RBV following hypertonic glucose appears to be a specific effect, possibly related to a decline in vascular tone."
http://www.ncbi.nlm.nih.gov/pubmed/12105252
Which suggests that a low-carb diet could simply allow the body to lose water that it's using to buffer glucose. That wouldn't mean that it's also losing glycogen, since glycogen is stored without water.