T Nation

Lipogenesis, Fact or Fiction?



I wanted to start this on it's own thread as there was a nice heated discussion in another thread but it wasn't the main point of the thread, so many might not find the valuable information. My recent past included time as an anatomy and physiology student.

One of the things we covered in pretty good detail was lipogenesis, which is the process in which carbs (glucose) is converted to bodyfat in mamals (humans). My books and my professors indicated that this process happened readily if carbohydrates were consumed in abundance of what the body could use short term, either to replenish depleted glycogen stores, or to use as energy immediately.

Well to my surprise, this doesn't appear to be how the body handles excess carbs in humans. Though it looks like more studies need to be done, it looks like when a meal is consumed and excess carbs are in the blood stream, the metabolism will increase to burn off the extra energy, while only a nominal amount will be converted to bodyfat.

However, it was observed that in a mixed meal, the abundance of carbohydrates effectively turned off any fat burning, causing nearly 100% of the fats consumed with the meal to be stored as bodyfat.

This information is really driving home for me the importance of JB's P&F and P&C meal splits. Further discussion is of course a good thing.



When I first began bodybuilding and didn't know anything -- which is the natural order of things -- I read Parillo's theories and advice which is much the same as above.

Guess what, on the Parillo diet that supposedly could not get one fat, I went from about 150 and who knows, maybe 12% bf (possibly a fair bit more: there was no measurement) to low 190's and thought I'd made big progress.

Actually I mostly got way fat. Going to a more standard bb'ing diet and continuing training and slowly losing about a pound per week, soon I was back down to 158 and 8% by skinfold (6% by hydrostatic, but the skinfold was the more plausible figure), and stronger than I was in the low 190's.

The "carbs don't turn to fat" theory got me nothing but fat.

In practice this does NOT pan out.

I am not saying Berardi's advice is not right or good. It is. But he does not claim that carbs cannot readily be converted to bodyfat. They most certainly can, and metabolism most certainly does not necessarily rise to equal any excess in carb intake relative to current needs.


This was exactly what I thought, but the study I posted seems to say otherwise and I could not find any scientific studies that included humans, to validate what I thought was correct. Do you have access to studies? I really want to get to the bottom of this, The study I posted seems to leave some wiggle room saying that Lipogenesis may in fact be happening in a considerable way in the adipose tissue itself. I would be interested in reading any more studies that deal with humans, I only add that because it seems humans and other lab animals handle this differently according to the above study.

I am going to give this a try in any event, It's not like i'm eating so clean right now that I'm going to blow up like the stay puffed marshmellow man. I currently get the majority of my carbs in my first few meals, but have not made any attempt at avoiding fat during these meals.



I really never tried to find studies on it. Back around the same time I read a popular book making similar claims to Parillo but for the average person, insisting that if fat intake was quite low then carbs just wouldn't be turned into fat and calories just didn't matter, and this book had many citations that the author was at least pretending supported his case.

(It is not unusual for references to be provided that in fact do not support the statement to which the reference is appended, unfortunately. Somehow, however, people see a reference number after a given statement and then assume that there must indeed be proof for it. Many authors take advantage of people's tendency to so assume.)

I never bothered looking into it in terms of the research because aside from my own disaster in practice, I have to learn that there are countless people, both in bodybuilding and not, who put on fat on low-fat, high-carb diets.

And so far as claiming it to be biochemically impossible or difficult, I never learned from science any such reason, that is for sure.

Whether it is so for rats, I have no idea. Rats, having a much higher ratio of surface area to mass, can shed heat a lot better than humans can, and certainly differ in amount of brown-fat thermogenesis. It may well be that they much more readily increase their metabolism in response to increased caloric intake from carbohydrates than humans do. Don't know, haven't looked into it.


I'm not necissarily talking low fat diet, just not in the same meal as a high carb meal. I think if you excluded anything it would spell dissaster for the energy systems of the body. I could see how an alltogether low fat diet would cause the body to stop burning fat as a fuel source and thus might cause lipogenesis to occur more efficiently.



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Yes, just to repeat, I'm not at all critizing what Berardi has said. His approach is effective and sound.

As opinion, I think it is effective both for the reasons he states and because in practice it helps with calorie control in a rather automatic way. This latter effect shouldn't be minimized or thought unimportant, or in the slightest way invalidating.


That the author points out the actual researchers' reservations about using the hepatic de novo data does coincide with what we continue to learn about adipose tissue (how hormonally active it is, etc)

Unrelatedly, I believe the greatest value of the whole P+F/P+C split is where it gets beginners comfortable with limiting their carbs intake. And I do know that discovering my own carbs tolerance was an important part of my own journey.


The author here states that the study was done where the energy from carbs consumed was not in excess of the body's total energy expenditure (TEE). For the average sedentary person, I imagine it's quite easy to eat carbs alone in excess of TEE, and this is apparently where de novo lipogenesis occurs.

If total energy intake (carbs and fat) is less than TEE, I imagine you won't be putting on much fat, if any...provided you're working hard enough. Then it's just a matter of giving your body enough carbs AND fat to perform well.


From my point of view, the actual grams of carbs daily isn't as important as the actual glycemic load daily. And all process to re-distributed glucose (from carbs) to glycogen versus fat it depends on the threshold of release of insulin.

I you try to maintain a low threshold of insulin to X amount of carbs is suitable to drive to muscular glycogen production because the muscular cell has a low threshold to insulin.
If you produce high amount the insulin to the same X amount of carbs, they will be stored as fat because the adipocytes have the insulinâ??s gate with a high threshold.

And one more thing, to let glycogen cross to the muscle cell membrane, is necessary water, minerals, amino acids, sodium and fat. For this reason mix up fats with carbs meals is important (obviously no high carb high fat meal). Playing with the IG of carbs, good fats and the threshold of insulin can be very useful both fat loss or building mass with a propoer timing.


I've always been under the impression that lipogenesis is very real and occurs when ATP and glucose levels are high. This condition leads to an accumulation of glyceraldehyde phosphate and acetyl CoA. These intermediates of glucose metabolism initiate triglyceride formation, with acetyl CoA forming the fatty acids and glyceraldehyde-PO4 into glycerol.

During lipid oxidation lipids are broken down into glycerol and fatty acids by lipase. Glycerol is converted into glyceraldehyde and beta oxidation in the mitochondria converts fatty acids into acetyl CoA. Perhaps the ingestion of fats with carbs increases cellular levels of acetyl CoA and glyceraldehyde-PO4 thus spurring lipogenesis to a greater extent than the ingestion of carbs without the lipids could. I don't actually know I am just thinking out loud here.


Here's an interesting anecdote from my experience: When I was in the military, I got gallstones from a hereditary condition. They couldn't schedule the surgery to remove my gallbladder for about 2 months. When you have gallstones, eating fat causes the gallbladder to contract and squeeze the stones, causing the worst pain I have EVER had. So, for those 2 months, I ate ZERO fat. However, I ate TONS of carbs.

Mostly, my diet consisted of grilled chicken breasts or lean fish, and a steamer full of rice w/ soy sauce. I also would eat entire packages of pasta with a fat-free sauce. I wasn't training particularly hard, this was before I really knew how to train, so I worked out like a pussy and played racketball and hockey mostly. So, with all those carbs, and basically no training effect, I lost over 20 lbs. of fat in 2 months. Had to buy all new pants. I've often wondered what would happen if I followed that same diet while training hard. I've never had the guts to try again, especially knowing the value of EFA's. Maybe include 1 P+F meal of lean protein w/ a bunch of EFA's pre-bed?


By not tracking calories it's impossible to say. But, you cut out fat almost completely, and considering fat is very calorically dense, you dropped your calories.

Whenever you drop a major macro you will most likely be in a caloric deficit. Not a surprise you lost bodyweight.


If nothing else one can rely on some very basic and unavoidable facts.

The only things that can happen with carbohydrates, fat, or protein once absorbed into the bloodstream are:

1) They can be burned, yielding CO2 and water (or also ultimately) urea, and thus eliminated from the body. Or

2) Their mass can be incorporated into the body.

Absorbed fats, carbs, and protein can't be breathed out (except after being burned), pissed out (except for the nitrogen content in protein after being burned), or escape via the ass. A small amount is lost from shed skin and hair but this is not important: there is also some nitrogen loss in sweat but I am not sure if this before or after protein is burned, or both.

So in other words if calories are absorbed the amount in excess of what is burned IS going to go to increased weight, usually fat. And the idea that the amount that is burned will automatically go up to match intake pretty much no matter what it is, is not correct. In fact it generally is not true at a 1:1 ratio for anything about usual maintenance. That is to say, the thermic effect of added food beyond usual maintenance is normally not fully equal to the added calorie intake.

There is no magic way for them to have some other fate, such as in the radio ads for thermal wrap treatments that supposedly result in major fat losses and "shrinking of fat calls" from a single treatment. (Where does the fat supposedly go? Does the starship Enterprise cruise by and beam it out?)


This is good basic understanding, everyone should realize this, I hope. I think where all the different diet and meal plan strategies come from is that the food you eat, and when and how you eat it does in fact have an influence over how your body uses it, what you resting metabolic rate is, etc... So while total calories is very important to either building or tearing down the body, I also feel that there are ways to manipulate what when and how you consume nutrients to have the greatest effect of burning bodyfat, and or building muscle.

One of the ideas which doesn't sit well with me is the idea that to gain muscle you also need to gain some fat along with it. And to lose fat you will also lose some muscle. I think the holy grail would be a diet or nutrition strategy which would allow us to gain muscle while losing fat or keeping it to a baseline figure once that figure is reached.

In my mind what would be an optimal strategy would be to consume one large P&C meal with a low GI carb like oatmeal with very little fat as a first AM meal. Then have all other meals of the day be P&F in a calorie amount that would be suitable to your overall current goals, for instance if burning fat was your priority, these meals would be slightly lower in total calories so that your body will look to reserves shortly after the meal is used up. Then around your workout time, you would go with High GI carbs and protien, this would build muscle. So in one day you could effectively burn some fat and build some muscle, if you do this day in and day out, why would it not be possible to say over 2 months, gain 5 lbs of muscle and lose 5 lbs of fat? If done for a year could one possibly realize gaining 30 lbs of muscle and losing 30 lbs of fat? Even if half of that was possible, wouldn't gaining 15 lbs of muscle and losing 15 lbs of fat be a very good result for a 1 year period?



i've had numerous arguments with people on this site saying lipogenesis is insignificant. it gets old


The theory is that in humans, Lipogenesis is not as profound as one would assume. The effect of people getting fat seems to be that carbs shut off fat burning so when a mixed meal is consumed, nearly ALL of the fat intake is stored as bodyfat. Using this theory, one could consume considerably more carbs on a daily basis, and avoid consuming them with fat and bodyfat storage would be minimal. However it seems as if there is still a grey area when it comes to the role of adipose tissue and lipogenesis rates occuring in them. I think the study I posted used figures that if you ate 500G carbohydrate meal, only around 5 grams is converted to fat via lipogenesis. So not that it doesn't exist, but that it doesn't happen to the extent previously thought. It's just a theory, but it does make JB's guidelines more scientifically relavant.



Did you read the study I posted? I'm not saying it's 100% conclusive, but if you can point me to a study which shows the opposite I would greatly appreciate it. I have no vested interest in which theory is correct, only that I can say I know which theory is correct.



So I take from this that you should have a burger patty, or a bun, but not both at the same time?


So what happens to the 2000 calories?

BMR goes up by an extra 2000 calories over those few hours?

I really don't think that's the case.

Let's say glycogen stores are nearly full. If so, then where does this matter go, if not to fat?

The carbs are not going out the urine, the feces, the breath, or sweat as such.