Separating Fats & Carbs

Just some musings on carbohydrates and fats, but with a scientific basis so put it here.

Personally I believe the obesity epidemic can be blamed primarily on two phenomena:
1.  The abundance of high calorie foods high in fats & carbs (I'll call them CF) in ever larger portions, and
2.  Liquid calories loaded with sugar and/or fat

To prevent obesity my solution is simple:  Keep the fats and carbs separate.  If you're going to eat carbohydrate, eat it with lean protein and/or in whole form so you get sufficient fiber.  Go easy on the fat.  If you're going to eat fat, chances are it is attached to protein, forgo the carbs.  If you simply must eat CF foods, rely on portion control/calorie counting and not on satiety to determine how much you eat.  Keep the total caloric load low, perhaps in the 2-300 cal range, to keep the unnatural assault on your metabolism to a minimum.  

My reasons for this are twofold:

1.  Our paleolithic ancestors, from whom we differ very little genetically, did not have access to foods that were rich in both lipid and carb content simultaneously.  I don't envision Paleo dude saved up his tubers to cook in rendered wild boar fat to plate tuber fries with his boar ribs and a side of some veggie also cooked in boar fat.  It seems far more likely that  Paleo dude ate the tubers if in abundance perhaps even delaying the need for a hunt, or saved those tubers for a rainy day when a kill was available for the eating.   Paleo dude was mostly an opportunistic eater in a scarce world.  Obesity was not a problem nor did Paleo chick worry over a little belly roll.  We are programmed to store energy in its most efficient form (lipid) in amounts that are seemingly unlimited.  There would have been no evolutionary advantage to not being able to store energy, or not wanting to partake in this energy source during times of abundance to save for times of scarcity.    There is no physiological reason to limit lipid intake on any given day.  I see no reason to doubt Eaton's work indicating that Paleos ate a relatively low fat diet.  Further underlining the need for taking it while they could get it -- e.g. overconsumption one day if necessary -- and weak signaling at best.  Bottom line, our metabolisms seem designed to switch between fuels depending which was more available, not deal with being bombarded by mixed fuels.

(2) As outlined in Nutrient Fates After Absorption  dietary intake of protein and carbohydrate share the following in common:
(a) they invoke an insulin response
(b) they are on the order in terms of quantity with the body's storage capacity (nitrogen "pool" and glycogen)
(c) their intake stimulates their metabolism (protein synthesis, oxidation)
(d) their absorbed form is as metabolic substrate (amino acid, glucose)

As such, our hormonal signaling is tightly attuned to intake of these macronutrients to maintain levels in a relatively narrow window.  Dietary fat, OTOH, is
(a) once absorbed, packaged as triglycerides in chylomicrons and transported mostly to the adipose tissue for immediate storage.
(b) as chylos, the absorbed form is not the metabolic substrate for lipids, that being free fatty acids (NEFA/FFA).
(c) in quantity, orders of magnitude less than total stored lipid even in the leanest of humans
(d) can virtually be stored without limit thus eliminating any need to limit intake in one feeding

Circulating NEFA levels are controlled indirectly by release from storage.  Dietary fat does not significantly contribute directly to the levels of this energy source.  My take-away message from the post/article is that our appetite/satiety signals are finely attuned to intakes of carb and protein out of necessity to maintain structure and storage/circulating levels within a relatively narrow range.  Our metabolisms change remarkably within 24-48 hrs of deprivation.  Lipid storage, even on a lean person, can last weeks (or more).  Even gorging on fat is a drop in the bucket of the amount of lipid we store (again, even in the lean), so there's no need to limit this in the short term.  Fat mass regulation seems almost independent of dietary fat when you think about it.


So, whenever I hear the query "Why do we overeat", in many cases it is a passive process.  Our bodies were not made to handle the caloric punch of CF foods, so we tend to eat more calories before the stop signals go up were we consuming just carbs (usually with lots of fiber) or fats (usually with lots of protein).


Over on the personal blog ( When to Eat ), Helen wondered about separating carbs and fats on a daily basis -- e.g. alternating high fat day(s) with high carb day(s).  This was actually the impetus for this post because my reply became too lengthy for the comments feature here to handle.  In any case, here are my thoughts on that:

Let's say during the day I have a fatty breakfast and a carby dinner or a carby breakfast and a fatty dinner.  Either way, if I'm consuming basically maintenance-caloric levels of these foods, my metabolism will do a bit of switching up within its normal mode.  After carbs, lipid oxidation will be down-regulated and the carbs burnt off or converted to glycogen (see that Nutrient Fate link), but as the glucose is "cleared", lipid oxidation ramps up again.  After fats, lipid oxidation remains as it was.  If there's no to minimal carb in the meal, insulin is likely low so NEFA are released from the fat cells to replenish the IMCL being "burnt".  The metabolism is "normal".  

It takes a few days, however, for the body to transition to a "fat burning" (low carb) metabolism.  Our bodies are inefficient during this transition -- spilling ketones, etc.  This can probably be used to our advantage to get a little more out of weight loss, but is it healthy?  I don't have the answer to that and I'll try to put it on my "to do list" to look into.  My educated guess is that so long as you're not overdoing it caloriewise this is probably OK as diacylglycerols and ceramides shouldn't build up.  It takes a while for IMCL to accumulate anyway on an HF diet.  I don't know if it will accumulate if one's "average" diet is HF, even if some days are LF.

From a weight loss perspective, I do feel this switching up was probably responsible for the whooshes I would experience upon returning to LC after carb cheats.  Was this healthy?  Who knows.  I look at it as a trade-off in the end.  Whatever I did to get here, I'm way better off for it now.

I worry more, however, over the transition from a HF day to a HC day.   The switch gets flipped back almost immediately.   I've posted that as little as a single high fat meal can induce IR, and impaired glucose tolerance (IGT) the following day.  If one is not efficiently burning lipids in short HF stints, this could potentially turn the HC day into a "diabetic day".  I've played with a glucose meter to see about this for myself.  Perhaps the fact that I don't eat particularly high fat (as a % or on a gram basis) version of LC, I've not had issues with tolerating carbs.   Meters are cheap, and you can get strips relatively inexpensively too.  Rather than guess, or look to studies to see, testing one's own response to this is probably better.    But I do think alternating days like this has a greater potential for creating issues than mixing it up "separately" throughout the day.  If one experiences a degree of IGT, I think a good bout of exercise between the last high fat meal and the first high carb meal might be all that's needed.

Companion post to follow ....


benn686 said…
Hi, what browser should I use to view this site, for best rendering?

(I'm using Chrome, and the page looks washed out.. gray text on white background)

CarbSane said…
I use Chrome mostly too. I like the gray, but didn't realize it might be difficult for others to read. I'll darken it up a bit in the settings. Thanks for reading!
Anonymous said…
I'm so so happy to find your blog! Thank-you so much for taking the time to compile this information. I have literally been on a roller coaster of eating disorders and obsessional thoughts about food since I was 16, and I am only now, having reached the tender age of 23, beginning to understand the social conditions from which this societal illness as I would deem it, has arisen. I think that the means by which we come to be provided with 'health' information is inherently flawed and is of particular benefit to industrialists, political, and economic interests. I think that peoples state of health, at least particular to where I live are a direct reflection of the ignorance regarding how we are socialised and the powers that be, so to speak. Also, I believe the way in which the educated classes have access to, and communicate through a language the 'lay mind', does not have the understanding to critically assess the value of, has a part to play in providing the conditions ripe for the incidences of illness. This elitism regarding access to information and its understanding further miseducates those who have not had access to such training, but potentially are just as 'educated', and 'intelligent'. Thats not to say that individuals don't have a responsibility for their own education and health or indeed that they do not have the potential agency or access to resources to provide it, but the environment in which we are socialised and the beliefs that are provided from the very first, generally regarding our own individual sovereignty I think is totally misguided. For instance, having an illness becomes deemed an individuals problem, rather than a problem generated through wider social priorities, values, organisation and conditions.

So again, thanks, I really appreciate such efforts as a source of education.
CarbSane said…
You're very welcome Jenna! Thanks for reading and sharing your thoughts. I'm happy to hear that at 23 you are making strides in your journey. If there's anything I can do to help with the eating disorder stuff, feel free to pick my brain over in the Chronicles. (Or, of course my Inbox is always open). I get sad sometimes that it took me this long to achieve this peace. But better late than never, right? I hope my example shows that it is possible to be RID of the disorders. I consider myself recovered ... cured ... NOT in recovery or anything like that. I fear we're in for another wave of eating disorders what with how they are handling the childhood obesity issue.
MM said…

Speaking of rendering fat, I was looking through my "Nutrition and Physical Degeneration" by Weston Price. I came across this in the chapter on Eskimos. (Page 70 in my copy) "Seal oil provides a very important part of their nutrition. As each piece of fish is broken off, it is dipped in seal oil." I suppose they must have rendered it. I don't imagine when you cut open a seal, liquid oil pours out. :) Clearly they were not frying up plates of hash browns, though. He doesn't discuss the process at all.
CarbSane said…
I think it is important to remember that the Inuit/Eskimos are an adapted culture, not paleo. IOW, we didn't evolve from them.

So in *relatively* modern times, yes, they are known for rendering seal fat and apparently carrying it around in a flask -- like some do with alcohol ;) -- to sip for extra calories.

I've blogged on the high O3 content of Seal Oil too. My bottom line, most high fat dieters are consuming dramatically different fat types than the Inuit who are our "poster boys" for VLC/VHF diets.
Keenan said…
what do you think about an athlete eating mixed FC meals?
CarbSane said…
I think it's just fine. I'm not one to get hung up on the fact that in a mixed meal the fats go pretty much directly to storage while the carbs are burnt off, because later, those fats will be allowed to come out to play. For someone that is highly active, the caloric density of mixed meals probably won't be an issue.

I do think one of the reasons some do so poorly on Zone compared to lower carb or lower fat plans is b/c of the mixing and not being able to eat as much of the more calorically dense mixed meals to promote satiety.

I'm trying to "wing it" as ad libitum as possible which means I do best if I eat less fat with my carbs and less carbs with my fat. If I ever got my lazy arse in gear a bit more, I could probably get away with a bit more!

Thanks for reading and the question Keenan. Welcome to the Asylum!
Anonymous said…
>There is no physiological reason to limit lipid intake on any given day.

I commented on this earlier. IMO, if you put yourself in the position of a paleo man, especially, but also a paleo woman, the limitation would occur from the higher mind (probably subconscious but possibly conscious as well) rather than the lower brain stem, due to the fact that eating a lot of fat means pain when you have to run or climb trees or otherwise move your body when it is loaded down with fat. Obviously, there's a tradeoff. If food is scarce, you eat as much as possible, pile on the body fat, and then rely on the starvation that will soon follow to remove the body fat. But suppose a low-quality food is widely available (acorns or unappetizing nuts) and high quality food (meat) is hard to obtain. If you fatten up on acorns, you'll have a painful time chasing down the deer to get meat. So you naturally restrain yourself when it comes to eating nuts. The increased pain/reduced pleasure of not eating as much nuts as you want is offset by the reduced pain in running down deer, and the increased pleasure of eating the deer when you catch it.

I've noticed something like this when backpacking, and other backpackers have similar experiences. Namely, we lose weight very rapidly the first few weeks until body fat percentage drops to a low level, and only then does appetite kick in (when it does kick in, it kicks in with a vengeance). Evidently, the mind registers the pain of carrying that extra 10 lbs of blubber up and down the mountains and makes a decision to get rid of it as soon as possible.

Any activity where carrying excess fat is painful is likely to produce similar results: effortless weight loss until body fat is reduced to a very low level.
PaleoProof said…

Thanks for creating the website. I found you after listening to a podcast you did with Jimmy Moore. I have been eating lowcarb, very low carb and high fat since last October 10. Since then I have gone from 150lbs to 174lbs. Before, I was eating vegetarian, low fat and after reading various Paleo Books/low carbs and began a high fat diet. The more I gained the more fat I would eat and lower the carbs. I just have continued to gain weight. Plus, I hve gone to eating only 3 to 2 times a day also. Until, I read your blog I thought I was still doing something wrong. When in reality I hve probably increased my calorie level from 2000 calories a day to 4000 while stopping my chronic cardio routine. I was also running 8 miles a day during the week and 20 miles on the weekend. I was thinking I was killing my self according to mark sisson and gary taubes. I think I should return to a much lower fat diet and caloric controlled to get my weight back off.
CarbSane said…
Welcome PR! LC works magic for me for weight loss *to a point* but I doubt it would have doing it the "right" way (high fat). You might want to just avoid added fats and choose leaner proteins. The only thing I even loosely track these days is my protein. I aim for ~100g and the rest seems to take care of itself.