(Source [ironically]: Gograins.com.au)
Fasting and ending up with a bigger waist; how is that possible?
Contrary to popular belief, this is very unlikely to be due to the body turning muscle protein into glucose, and then converting that glucose into fat for storage in fat cells around the waist. When you are fasting, one factor strongly opposes that transformation. The body is in net body fat release mode, due in part to low circulating insulin, and thus body fat cells are essentially rejecting glucose. Blood glucose levels are maintained, to feed the brain, but uptake by adipocytes via GLUT4 isn’t happening.
So where does the bigger waist come from?
When people fast they typically drink water, quite often lots of it. A reasonable explanation for the bigger waist is that body fat cells store water in place of fat, as fat becomes energy. Since water is denser than fat, the stronger gravitational pull will lead to a larger bulge around the lower abdominal area, increasing waist circumference at the point it is widest. The amount of fat mass, however, is going down due to fasting.
In the obese, body fat cells generally become insulin resistant, even though many people believe the opposite to be true. This leads to the creation of new body fat cells (hyperplasia) to store the extra fat. If body fat loss is maintained over time, I’d expect the body to get rid of those fat cells that were created through hyperplasia during the obese period. The literature, however, seems to suggest that the number of body fat cells is set before adulthood, and does not change afterwards. I am skeptical, as the body seems to be very good at getting rid of cells and tissues that are not used.
The loss of those extra body fat cells may bring the number of adipocytes to pre-obesity levels, but for many people quite some time is needed for that to happen. Often in the order of months; maintaining reasonably low body fat levels.
So don’t despair if you end up with a bigger waist around noon after skipping breakfast, or before dinner after fasting the whole day. That may be a good sign; a sign that you are actually losing abdominal fat.
I'm hoping Cate Shanahan is right that fat cells go away via apoptosis under the right conditions (discussion starts around 20:00 on her podcast with Jimmy Moore).
ReplyDeleteFascinating. I'm not familiar with the phenomenon, but I can easily believe it.
ReplyDeleteAnd it may be more than simply high levels of water intake. The body's water budget is a complex and largely unexplored area of science. (My own body can be tenacious about storing water whenever my water intake is too low--perversely, low water intake can make me swell up.)
In the early stages of low-carb diets people often drop large volumes of water, and not just glycogen-associated stores--people watch their ankles go from swollen to svelte. Critics say, "Well, it's mostly water weight..." Sure. Extraordinarily unhealthy water weight.
None of this will be news to women out there, of course, whose hormonal cycles result in all manner of seemingly arbitrary changes in water retention and loss.
Interesting post Ned. I would not have thought of the extra water, but it makes sense. On the point about the body getting rid of cells it doesn't need, there is the related countervailing point in our book about how nucleii absorbed into muscle cells to maintain nuclear domain remain in the muscle even when it atrophies.
ReplyDeleteHi Beth, thanks for the link. I’m not sure the extra adipocyte elimination process relies on apoptosis. What happens may be simply a modified version of the normal turnover process, whereby fat cells previously created through hyperplasia are not “renewed”. I’m going to listen to that interview soon.
ReplyDeleteHi David. You are right. Water can shift from tissue to tissue even without intake, and water can be lost and retained independently from glycogen stores. Water is the main component of our bodies, and of most of our cells, including cells that either don’t store or store little glycogen.
ReplyDeleteHi Glenn. This post doesn’t contradict your conclusions. Muscle cells are very different from adipocytes. There is usually a big difference in size, among many other differences.
ReplyDeleteI found this study recently which seems to suggest that dehydration can potentially cause fat cells to multiply.
ReplyDeleteMaybe adipocytes really are more than just storage depots for fatty acids,
http://www.jbc.org/content/274/24/17042.long
Are you sure that is the right link Kindke? The article seems to be about endothelial cell apoptosis, and makes only tangential reference to adipocytes.
ReplyDeleteHi Ned,
ReplyDeletedo we know for sure? So which is it? Do the extra fat cells atrophy/die or not when not needed? Is Woo not right that because she lost all that fat her leptin is very low, which means her fat cells are signalling they are empty? I thought once they were formed you had them for ever. I suppose it depends how fat one was, or is.
Hi lightcan. I can’t answer with certainty because the literature is conflicting. However, from all that I’ve been able to piece together, it seems almost certain that if a formerly obese person maintains a low body fat percentage for a long time (e.g., this varies from person to person, and may go from several months to years) at some point a more permanent transformation occurs. The transformation involves changes in body composition and fat distribution that are consistent with excess body fat cells being lost.
ReplyDeleteI should also say, adding to my comment above to lightcan, that it seems that only a minute percentage of the formerly obese population reach that point. Really minute. Much smaller than the percentage that are able to lose body fat down to healthy levels (not showing a six pack, but enough to reduce the risk of most degenerative diseases) and keep that body fat off for more than 2 years, which is a very small percentage already.
ReplyDeleteOK, thank you.
ReplyDeleteI always liked to be in the minority.
I notice that when I do IF combined with LC, after a couple of days my belly gets soft and jelly-like - I look and feel fatter than before(
ReplyDeletesheyogafast they typically drink water, quite often lots of it. A reasonable explanation for the bigger waist is that body fat cells store water in place of fat
ReplyDeleteI have no paper/citation/etc. but I think it may be a shift of fat stores to visceral and/or deep subq abdominal fat. These fat depots are more metabolically active and when you're forced into "conserve mode" it seems reasonable that the body would shift what stores it has to where they are "needed"?
ReplyDeleteHi CS. I think that the shift in fat you mentioned makes sense, and may well happen, but it is difficult to explain the wider waist that so many people experience based on it, because: (a) there is no change of substance, it is fat turning into fat; and (b) some of the fat should be consumed during the fast.
ReplyDeleteAnecdotally, this wider waist phenomenon is seen in folks who were formally obese, and then lost a significant amount of body fat.
what if the mechanism behind this is that (as it is known) fasting facilitates lipolysis thus raising levels of FFA, but the rate of beta-oxidation is not fast enough to burn all of them, so (as it may be conjectured) they get re-absorbed into adipocytes but NOT throughout the whole body but in the most metabolically active region - midsection?
ReplyDeleteHi Anon. Because if the rate of lipolysis goes up, to the point of an increase in circulating FFAs, there will be more fat leaving adipocytes than coming back in.
ReplyDeleteYou, sir, do not understand gravity.
ReplyDeletewhy you don't ask it to your doctor sweetheart? it sounds very strange.
ReplyDelete