3

votes

Gluconeogenesis Vs De Novo Lipogenesis

Answered on August 19, 2014
Created February 04, 2012 at 12:47 AM

My question is why is it ok to push your body to produce most/all of your carbs from protein while it's ridiculous and unhealthy to allow your body to manufacture the fat you need from carbs? How are the systems fundamentally different?

To reframe the point - How is eating 20gm of fat different from eating enough fruit to have your body produce 20gm of fat?

3bad4b0b105bf44d7650e7fdfbe15cbd

(860)

on February 06, 2012
at 02:08 AM

The body creates palmitic acid as the end-product of lipogenesis. It's a saturated fatty acid. http://themedicalbiochemistrypage.org/lipids.html. See the table near the top/middle.

Ca2c940a1947e6200883908592956680

(8574)

on February 04, 2012
at 03:52 PM

But is that really efficient? If I need fatty-acids I should eat that which provides them easily, no?

Ec39179d4c06199471827a706adb2896

(242)

on February 04, 2012
at 06:35 AM

There is no such thing as an "essential carb" but there do exist essential proteins and fats.

1c67bc28f4e44bbb8770b86df0463df3

(6719)

on February 04, 2012
at 05:47 AM

This question should be deleted.

1c67bc28f4e44bbb8770b86df0463df3

(6719)

on February 04, 2012
at 05:41 AM

The real question is how many other animals posses the ability to become obese in the same manner as humans do (via massively enlarged subcutaneous fat stores). Stored 'human fat' is simply Triglycerides composed of 3 fatty acids with a glycerol backbone, and their are many variations (chemically/atomically/etc).

1c67bc28f4e44bbb8770b86df0463df3

(6719)

on February 04, 2012
at 05:21 AM

Eating enough fruit to have your body producing 20 grams of fat is not physiologically likely under anything other than completely abnormal and unrealistic conditions.

5e36f73c3f95eb4ea13a009f4936449f

(8280)

on February 04, 2012
at 02:43 AM

You need a biochemist to answer that. As far as I can recall, there's a bunch of different fats under the "fatty acid" umbrella, and there are various steps they convert between. However, you are making the assumption that 1) Fatty acids are palatable, 2) Fatty acids pass through the digestive system unchanged.

Fb67dc30cead043d1d13ea503a3044dc

(3280)

on February 04, 2012
at 02:03 AM

What're you blaming Nance for? She's not a moderator, she can't delete your accounts. And she at least tried to answer your question.

96bf58d8c6bd492dc5b8ae46203fe247

(37227)

on February 04, 2012
at 02:01 AM

Say again, over--I haven't flagged anything today.

77877f762c40637911396daa19b53094

(78467)

on February 04, 2012
at 01:59 AM

So a new account again. Isn't it interesting that 30 seconds after posting my account was deleted because you didn't like the question. This site is worse than the people at 30 bananas a day.

96bf58d8c6bd492dc5b8ae46203fe247

(37227)

on February 04, 2012
at 01:49 AM

LOL, you added 1 + 1 and got 3. I haven't flagged anything. And I totally love carbs and have always eaten as much fruit and fresh vegs as I can tolerate but sadly that amount is only moderate. So no, I'm very pro-carb as reading many of my posts would demonstrate. I'm always the one arguing on behalf of eating fruit.

77877f762c40637911396daa19b53094

(78467)

on February 04, 2012
at 01:47 AM

Is that why you've been flagging my posts? I eat 50% fat and just recently up'd my carbs. I am in no way anti-fat. Why are you anti-carb?

77877f762c40637911396daa19b53094

(78467)

on February 04, 2012
at 01:45 AM

Excellent. Could you help me with my other question? I have had my account deleted twice for asking and I don't get why. What is the fatty acid content of fat created via de novo lipogenisis? It seems to me that we should be eating fat similar to that our body creates and I'm just wondering what that would be. I don't know why the moderator went nuts on it.

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5 Answers

4
96bf58d8c6bd492dc5b8ae46203fe247

(37227)

on February 04, 2012
at 01:44 AM

Others can give you the scientific answer; I'll just give you my practical, real-life answer.

I happen to love fruit--seriously so. But if I eat more than 3 whole fruits in one day or have more than 1/2 cup of starchy food such as sweet potatoes or rutabagas, I feel like crap. And if I go over 3 pieces of fruit my blood sugar becomes volatile--still normal fasting or 2 hrs after eating, but MUCH higher post-prandial spikes.

When I stay under 80g of carbs per day, I have sky-high energy and great bg and I gradually lose body fat. BIG DIFFERENCE!

It's starting to seem like you have an anti-fat agenda here and I'm getting bored so I won't read any more questions like this one.

96bf58d8c6bd492dc5b8ae46203fe247

(37227)

on February 04, 2012
at 02:01 AM

Say again, over--I haven't flagged anything today.

77877f762c40637911396daa19b53094

(78467)

on February 04, 2012
at 01:59 AM

So a new account again. Isn't it interesting that 30 seconds after posting my account was deleted because you didn't like the question. This site is worse than the people at 30 bananas a day.

77877f762c40637911396daa19b53094

(78467)

on February 04, 2012
at 01:47 AM

Is that why you've been flagging my posts? I eat 50% fat and just recently up'd my carbs. I am in no way anti-fat. Why are you anti-carb?

96bf58d8c6bd492dc5b8ae46203fe247

(37227)

on February 04, 2012
at 01:49 AM

LOL, you added 1 + 1 and got 3. I haven't flagged anything. And I totally love carbs and have always eaten as much fruit and fresh vegs as I can tolerate but sadly that amount is only moderate. So no, I'm very pro-carb as reading many of my posts would demonstrate. I'm always the one arguing on behalf of eating fruit.

Fb67dc30cead043d1d13ea503a3044dc

(3280)

on February 04, 2012
at 02:03 AM

What're you blaming Nance for? She's not a moderator, she can't delete your accounts. And she at least tried to answer your question.

2
510bdda8988ed0d4b0ec0b738b4edb73

(20888)

on February 04, 2012
at 04:34 PM

First, I don't think anyone said that its ok to "push" your body to make glucose. I think the consensus is that you can make sugar if you need it, where as you can't make protein or fat if you need it. So carbohydrates aren't essential to life. That doesn't mean zero/low carb is optimal to life.

Both gluconeogenesis and de novo lipogenesis are things you body does to manage your sugar levels. If you don't have enough, your body can make some and if you have too much your body can get rid of it. I'd argue that neither is really "good" for you. They both take energy and your body would rather probably do something more useful. But if your brain (or something else) needs sugar, your body will make some. Likewise, if you gorge on fructose your body has to get rid of it. It's a highly reactive oxidizing agent in your body, so you need to do something to make it more stable. Step 1 is to store it as glycogen, but there's only so much of that you can store in your muscles and liver. Step 2 is to convert it into fat. Fat (particularly saturated fat) is a very chemically stable molecule and as a result lots can be stored very safely (from a chemical standpoint). Your body doesn't really care about the long term effects of having too much fat in your system, all it cares about is getting the highly reactive toxic sugar (particularly fructose) out. So that's why we have the ability to turn sugar into fat.

I'd argue that if your body is relying on gluconeogenesis you're not eating enough carbs; however, if you're doing de novo lipogenesis you're eating too many. Sugar is safe in the body only in a very narrow range, think of all of the feedback loops we have in our body to manage sugar levels.

Personally, from a chemical standpoint, I'd rather be a little low on sugar than high. Sugar is highly reactive and I don't like the thought of having extra floating around my body waiting to be turned into fat. I'd rather just make it on demand for the systems that must have it.

2
3846a3b61bc9051e4baebdef62e58c52

(18635)

on February 04, 2012
at 03:54 AM

You're not "pushing" anything. It is a process that occurs. Ingesting carbs are not a requirement for life....fat and proteins are....thats the most basic truths without getting all up in it. BUT, will you be better off for "optimal health" with some carbs?...Jury is kinda out on that far as I'm concerned, so I don't argue that point since I think it is mainly dependent on previous health state, age, hormonal status, and so on and so forth.

Ec39179d4c06199471827a706adb2896

(242)

on February 04, 2012
at 06:35 AM

There is no such thing as an "essential carb" but there do exist essential proteins and fats.

2
5e36f73c3f95eb4ea13a009f4936449f

(8280)

on February 04, 2012
at 01:42 AM

Converting the carbs to fatty acids is long down the chain. The body's not going to do that when it can use the carbs as is (especially if your glycogen stores are low). By the time it gets to the fatty acid stage, it's to store it because all your energy needs are met and it can't make more glycogen.

77877f762c40637911396daa19b53094

(78467)

on February 04, 2012
at 01:45 AM

Excellent. Could you help me with my other question? I have had my account deleted twice for asking and I don't get why. What is the fatty acid content of fat created via de novo lipogenisis? It seems to me that we should be eating fat similar to that our body creates and I'm just wondering what that would be. I don't know why the moderator went nuts on it.

1c67bc28f4e44bbb8770b86df0463df3

(6719)

on February 04, 2012
at 05:41 AM

The real question is how many other animals posses the ability to become obese in the same manner as humans do (via massively enlarged subcutaneous fat stores). Stored 'human fat' is simply Triglycerides composed of 3 fatty acids with a glycerol backbone, and their are many variations (chemically/atomically/etc).

5e36f73c3f95eb4ea13a009f4936449f

(8280)

on February 04, 2012
at 02:43 AM

You need a biochemist to answer that. As far as I can recall, there's a bunch of different fats under the "fatty acid" umbrella, and there are various steps they convert between. However, you are making the assumption that 1) Fatty acids are palatable, 2) Fatty acids pass through the digestive system unchanged.

3bad4b0b105bf44d7650e7fdfbe15cbd

(860)

on February 06, 2012
at 02:08 AM

The body creates palmitic acid as the end-product of lipogenesis. It's a saturated fatty acid. http://themedicalbiochemistrypage.org/lipids.html. See the table near the top/middle.

1
96440612cf0fcf366bf5ad8f776fca84

(19463)

on February 04, 2012
at 08:38 PM

Eating twenty grams of fat does not expose you to the ill effects of glycation, and reactive oxygen species that burning carbs provides, or if you're getting it from fruit higher in fructose, remember that that fructose is 10x worse a glycator than glucose.

If you're getting it from fruit, it's not too terrible a hit on your liver, if you're getting it from sugar, since there's little fiber, it gets absorbed quickly and your liver has to dispose of the fructose half in the sugar rapidly.

Not to mention the insulin spikes if you go over the threshold.

In terms of neoglucogenesis, it's less efficient, which means that some of the protein is wasted in the process.

You're better off with the fat, if all you're worried about are the fat vs carbs macros.

Now, if you're doing a PWO, carb refeed, and that's what you're after, you can't eat fat instead as fat gets turned into triglycerides or ketones, so if you've depleted your muscle/liver glycogen, the only thing you can do is to eat carbs, or have your body produce them by catabolizing muscle, if not enough protein is being digested.

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