8

votes

If carbohydrates are converted to saturated fats, why are sat fats an important dietary requirement?

Answered on August 19, 2014
Created September 13, 2011 at 3:46 PM

A friend of mine asked me this while I was explaining why saturated fats are vital and the many benefits of eating sat fats such as: enhanced immune function, increased incorporation of calcium into the skeletal structures, lowering Lp(a), antimicrobial properties, etc..

He then asked the question, "how come saturated fats that are converted from carbohydrates don't deliver the same benefits?" What, specifically, about eating saturated fats from foods is different from the saturated fat we accumulate from converting dietary carbohydrate?

9e20abb05f3f6e3cc4bb107f8980aecd

(5939)

on September 14, 2011
at 04:01 PM

Anish - Metabolism of glycogen for exercise is healthier than metabolism of glucose for glucose disposal, which is what I was concerned about.

9e20abb05f3f6e3cc4bb107f8980aecd

(5939)

on September 14, 2011
at 03:59 PM

Hi cliff - Lipids includes cholesterol, saturated and monounsaturated fat, and other compounds present in cell membranes and matrix. A lipid deficiency may be reflected in low serum cholesterol leading to impaired immune function (see my recent LDL series), in a deficiency of the steroid hormones derived from cholesterol, in a reduced ability to build muscle in response to exercise due to deficiencies of saturated and monounsaturated fat, and other effects.

03fa485bfd54734522755f47a5e6597e

(3944)

on September 14, 2011
at 03:23 PM

Cliff, maybe because it's hard to eat *just* enough carbs to supply one's glucose needs without getting any extra and producing unnecessary insulin and everything that goes with that. If you let your body produce the glucose it wants, presumably it'll produce just enough and no more.

77877f762c40637911396daa19b53094

(78467)

on September 14, 2011
at 02:16 PM

Most people really need coca cola.... meh...

E5c7f14800c5992831f5c70fa746dc5c

(12857)

on September 14, 2011
at 11:53 AM

whole food carbs have nutrients though... :)

77877f762c40637911396daa19b53094

(78467)

on September 14, 2011
at 11:20 AM

Fat doesn't influence insulin, carbs does. So, the difference is obviously hormonal. Protein rises ghrelin too, carbs do not. Insulin inhibits lypolisis. There is no other mechanism to control blood sugar apart from insulin, which means, genetically, we don't need redudant pathway as it was never ingested much. External fat comes with vitamins and other stuff. It may also provide more training grounds for immune system cause of greater endotoxin exposure. Carbs on other handm, can only induce AGEs.

77877f762c40637911396daa19b53094

(78467)

on September 14, 2011
at 11:16 AM

Its not the same when you eat fat and when you produce fat. Fat from external sources comes with vitamins and fat soluble nutrients, unlike that which is generated.

6ec8d30130a6fb274871314533b5536b

(581)

on September 14, 2011
at 04:25 AM

pictures might help...

21fd060d0796fdb8a4a990441e08eae7

(24543)

on September 14, 2011
at 02:34 AM

Yes and yes. Now the pressure's on--gotta find the paper that says cholesterol doesn't fully reinforce membranes in a high PUFA diet.

8a3fdcbbec724506de15c14bb6271264

(435)

on September 14, 2011
at 02:10 AM

glycolysis is health damaging? isn't it used everytime we do anaerobic activity?

8a3fdcbbec724506de15c14bb6271264

(435)

on September 14, 2011
at 02:09 AM

I thought the body pulls cholesterol from the blood into cell membranes when they become too fluid. Cholesterol gives it rigidity. In fact, isn't this how the conventional wisdom of eating PUFAs to lower cholesterol works? The PUFAs go and make the membrane too fluid and serum cholesterol is "lowered" because it's being pulled into these membranes to give them rigidity (make them less fluid).

E5c7f14800c5992831f5c70fa746dc5c

(12857)

on September 13, 2011
at 08:55 PM

do we have evidence of lipid deficiency? I've heard that certain new guinea tribes eat 90% carbs with no ill effect?

21fd060d0796fdb8a4a990441e08eae7

(24543)

on September 13, 2011
at 08:30 PM

That is the question! I don't know much about fluidity and lipid rafts and stuff. But there are several papers like this about (excess fluidity?) being bad...http://www.ncbi.nlm.nih.gov/pubmed/21845733

21fd060d0796fdb8a4a990441e08eae7

(24543)

on September 13, 2011
at 08:23 PM

Cliff- I suspect #1 is not necessarily pointing to inadequate EFA. Lipid deficiency could be manifested in other ways, such as difficulty in absorbing fat soluble vitamins on a low-fat diet.

Medium avatar

(39831)

on September 13, 2011
at 08:21 PM

I might be more convinced if I saw another study that showed differences in immune system efficacy between a particular type of membrane phospholipid vs. another in WBCs. Do we know that these cells are qualitatively *worse*?

21fd060d0796fdb8a4a990441e08eae7

(24543)

on September 13, 2011
at 08:19 PM

See Paul Jaminet's post to support why ingesting carbs would not lead to the same outcome as ingesting saturated fat.

21fd060d0796fdb8a4a990441e08eae7

(24543)

on September 13, 2011
at 08:17 PM

Cliff- eating "carbs that turn into sat fat" and eating "sat fat" are not the same thing, no? Two isocaloric diets, with one having some saturated fat replaced by carbs, would provide less saturated fat to cell membranes because some of the carb would be used to produce glycogen and fuel brain/stuff. The above paper simply shows that membrane composition differs significantly between diets with different fatty acid ratios, which is an internal link between added saturated fat and membrane changes. See the last line I wrote "although this was not direct addressed..." Is that logic off?

Medium avatar

(39831)

on September 13, 2011
at 07:31 PM

It's definitely possible to create a net lipolysis with a very high saturated fat intake, but fat is simply so nutrient dense that a leptin-resistant person would not get as much satiety as expected and could easily eat their way to lipogenesis or at least weight stasis. The typical concomitant lowering of carbohydrate intake results in lower insulin (if there aren't hyperinsulinemia problems) and a constant release of FFAs. These must be met with activity to consume them, however, or they will just be recycled back into the adipocytes.

Ed71ab1c75c6a9bd217a599db0a3e117

(25472)

on September 13, 2011
at 07:20 PM

good point cliff

Af1d286f0fd5c3949f59b4edf4d892f5

(18472)

on September 13, 2011
at 07:18 PM

Travis, how come people can lose weight so well on high SFA diets? Not challenging you per se, just wondering.

E7a462d6e99fec7e8f0ddda11b34a770

(1638)

on September 13, 2011
at 06:34 PM

Don't really know - don't really care. (Cliff, imagine I'm saying this in a joking tone of voice WITH a grin so you know I'm not trying to blow you off, OK?) I just think that in general working WITH your body is usually better than working against it.

E5c7f14800c5992831f5c70fa746dc5c

(12857)

on September 13, 2011
at 06:18 PM

Is #1 even true? EFA needs are extremely easy to meet.

E5c7f14800c5992831f5c70fa746dc5c

(12857)

on September 13, 2011
at 06:17 PM

How come so many vlc's advocate making carbs out of prot?

E5c7f14800c5992831f5c70fa746dc5c

(12857)

on September 13, 2011
at 06:16 PM

This had nothing to do with the question. Carbs that turn into sat fat do the exact same thing.

9d741bcbe702044635f2ce3078043054

(1435)

on September 13, 2011
at 06:12 PM

I think this is good evidence that sat fat IS a necessary component of our diet. Saturated fats have straight chains that are what the cell membrane needs. When the cell membrane uses unsaturated fats, the structure is changes because these fats have "kinked" chains that don't line up as well. If the body was perfectly happy manufacturing saturated fat, it would not use unsaturated fats to construct cell membranes. And since you always have some amount of unsaturated fat in your diet, eating saturated fat is necessary to ensure the proper fats are available for membrane construction.

Medium avatar

(39831)

on September 13, 2011
at 05:22 PM

For a weight stable person, eating a significant portion of your diet as saturated fat is fine, but if one is attempting to decrease body fat, going nuts with a high SFA intake is a big risk.

4781cf8ae1bfcb558dfb056af17bea94

(4359)

on September 13, 2011
at 05:09 PM

Saturated fat is not a dietary requirement. That doesn't mean it is not healthy.

Af1d286f0fd5c3949f59b4edf4d892f5

(18472)

on September 13, 2011
at 05:06 PM

right. this is why i think it is probably not a good idea to avoid sat fats altogether. i think eating some sat fats is a very good thing to do. maybe 60% high fat Paleo is not necessary (maybe not detrimental either though) but I think at least eating some sat fat is a good thing to do so that your body can keep healthy cell walls.

Eecc48184707bc26bce631485b5b7e34

(4764)

on September 13, 2011
at 04:30 PM

Main reason is that we save our bodies the incredible stress associated with higher blood glucose and excessive insulin production. Carbs aren't the problem, it's the amount of carbs most eat that become problematic in combination with the amount of polyunsaturated fat we eat.

Af1d286f0fd5c3949f59b4edf4d892f5

(18472)

on September 13, 2011
at 04:29 PM

yep. great points. and while sat fats might not be *necessary*, avoiding is also not necessary. also, there are different types of sat fats, of course. dairy is rich in palmitic acid. beef fat is more stearic acid. a lot of people think all sat fat is the same when it's not. i know you know this travis. I'm just adding some thoughts onto your comments.

  • 8a3fdcbbec724506de15c14bb6271264

    asked by

    (435)
  • Views
    8.4K
  • Last Activity
    1399D AGO
Frontpage book

Get FREE instant access to our Paleo For Beginners Guide & 15 FREE Recipes!

8 Answers

best answer

14
9e20abb05f3f6e3cc4bb107f8980aecd

on September 13, 2011
at 04:34 PM

1) There's a limit to how much glucose will be converted to fat. As a result, people on low-fat diets, eg macrobiotic diets, become lipid deficient.

2) Some of the excess glucose is disposed of via glycolysis which is health-damaging.

3) Some glucose will be oxidized in mitochondria which is not as safe as fat oxidation.

In the end, you should eat what your body needs, not force your body to try to convert things you don't need into things you do need.

Remember also that your body needs both glucose and saturated fat, so the need to eat saturated fat for optimal health is not the same as the need to avoid carbs. The key point is that you can't meet your lipid needs on a 90% carb diet.

E5c7f14800c5992831f5c70fa746dc5c

(12857)

on September 14, 2011
at 11:53 AM

whole food carbs have nutrients though... :)

E5c7f14800c5992831f5c70fa746dc5c

(12857)

on September 13, 2011
at 08:55 PM

do we have evidence of lipid deficiency? I've heard that certain new guinea tribes eat 90% carbs with no ill effect?

E5c7f14800c5992831f5c70fa746dc5c

(12857)

on September 13, 2011
at 06:18 PM

Is #1 even true? EFA needs are extremely easy to meet.

8a3fdcbbec724506de15c14bb6271264

(435)

on September 14, 2011
at 02:10 AM

glycolysis is health damaging? isn't it used everytime we do anaerobic activity?

21fd060d0796fdb8a4a990441e08eae7

(24543)

on September 13, 2011
at 08:23 PM

Cliff- I suspect #1 is not necessarily pointing to inadequate EFA. Lipid deficiency could be manifested in other ways, such as difficulty in absorbing fat soluble vitamins on a low-fat diet.

77877f762c40637911396daa19b53094

(78467)

on September 14, 2011
at 11:16 AM

Its not the same when you eat fat and when you produce fat. Fat from external sources comes with vitamins and fat soluble nutrients, unlike that which is generated.

9e20abb05f3f6e3cc4bb107f8980aecd

(5939)

on September 14, 2011
at 04:01 PM

Anish - Metabolism of glycogen for exercise is healthier than metabolism of glucose for glucose disposal, which is what I was concerned about.

9e20abb05f3f6e3cc4bb107f8980aecd

(5939)

on September 14, 2011
at 03:59 PM

Hi cliff - Lipids includes cholesterol, saturated and monounsaturated fat, and other compounds present in cell membranes and matrix. A lipid deficiency may be reflected in low serum cholesterol leading to impaired immune function (see my recent LDL series), in a deficiency of the steroid hormones derived from cholesterol, in a reduced ability to build muscle in response to exercise due to deficiencies of saturated and monounsaturated fat, and other effects.

8
Af1d286f0fd5c3949f59b4edf4d892f5

(18472)

on September 13, 2011
at 04:04 PM

Well, a couple things to consider:

  • Many of the foods that are rich in saturated fat are also healthy to eat for other reasons besides the fact that they contain sat fat.

  • Eating foods that are high in carbohydrate (for most people, especially those on the SAD) means eating mostly unhealthy foods. There's a difference between someone who gets their carbs from good sources.

  • Excessive carbohyrdate to fat conversion can cause your body to actually store the fat instead of burn it. Many people run into this problem. Of course, if you consider all the other aspects and causes of obesity, as noted in recent articles from Stephan G and Jack Kruse and Chris Kressser etc... you know that the brain is highly involved as well.. but STILL, chronically eating loads of carbs and requiring your body to convert to fat can cause problems for a variety of reasons.

  • Just because the body converts it, doesn't mean it's smartest to force it to do so overabundantly. The better line of thinking is probably... if the body converts carbs to sat fat anyway, why not take the hint and just eat more sat fat?

Of course, everyone responds differently to specific macronutrient ratios. By now, we should all know this. Some do quite well on much higher carbs. Some do quite well on mostly fat from pure foods. I don't think eating loads of sat fat is necessarily required for good health. I think it's more accurate to say that if you are specifically trying to avoid sat fat foods, you are likely to run into trouble with what you are eating unless you are really educated correctly. Most people are definitely not, and this is where the masses run into major health problems.

7
21fd060d0796fdb8a4a990441e08eae7

(24543)

on September 13, 2011
at 04:58 PM

Not sure if anyone has mentioned the cell membrane argument.

Cell membrane composition differs significantly in a heavy butter vs heavy soybean oil diet: http://www.ncbi.nlm.nih.gov/pubmed/17002871

In this experiment, carb percentages were similar between groups. The difference in composition means that membrane fluidity and perhaps membrane receptor activity would differ between groups.

Bottom line is that I want my cell membranes to look like the cell membranes of my ancestors. Eating some saturated fat would presumably contribute to that, as it increases the LCFA composition of the membrane (although this was not directly addressed in the above study compared to a higher carb isocaloric diet).

E5c7f14800c5992831f5c70fa746dc5c

(12857)

on September 13, 2011
at 06:16 PM

This had nothing to do with the question. Carbs that turn into sat fat do the exact same thing.

21fd060d0796fdb8a4a990441e08eae7

(24543)

on September 14, 2011
at 02:34 AM

Yes and yes. Now the pressure's on--gotta find the paper that says cholesterol doesn't fully reinforce membranes in a high PUFA diet.

21fd060d0796fdb8a4a990441e08eae7

(24543)

on September 13, 2011
at 08:19 PM

See Paul Jaminet's post to support why ingesting carbs would not lead to the same outcome as ingesting saturated fat.

9d741bcbe702044635f2ce3078043054

(1435)

on September 13, 2011
at 06:12 PM

I think this is good evidence that sat fat IS a necessary component of our diet. Saturated fats have straight chains that are what the cell membrane needs. When the cell membrane uses unsaturated fats, the structure is changes because these fats have "kinked" chains that don't line up as well. If the body was perfectly happy manufacturing saturated fat, it would not use unsaturated fats to construct cell membranes. And since you always have some amount of unsaturated fat in your diet, eating saturated fat is necessary to ensure the proper fats are available for membrane construction.

Ed71ab1c75c6a9bd217a599db0a3e117

(25472)

on September 13, 2011
at 07:20 PM

good point cliff

Medium avatar

(39831)

on September 13, 2011
at 08:21 PM

I might be more convinced if I saw another study that showed differences in immune system efficacy between a particular type of membrane phospholipid vs. another in WBCs. Do we know that these cells are qualitatively *worse*?

21fd060d0796fdb8a4a990441e08eae7

(24543)

on September 13, 2011
at 08:30 PM

That is the question! I don't know much about fluidity and lipid rafts and stuff. But there are several papers like this about (excess fluidity?) being bad...http://www.ncbi.nlm.nih.gov/pubmed/21845733

Af1d286f0fd5c3949f59b4edf4d892f5

(18472)

on September 13, 2011
at 05:06 PM

right. this is why i think it is probably not a good idea to avoid sat fats altogether. i think eating some sat fats is a very good thing to do. maybe 60% high fat Paleo is not necessary (maybe not detrimental either though) but I think at least eating some sat fat is a good thing to do so that your body can keep healthy cell walls.

21fd060d0796fdb8a4a990441e08eae7

(24543)

on September 13, 2011
at 08:17 PM

Cliff- eating "carbs that turn into sat fat" and eating "sat fat" are not the same thing, no? Two isocaloric diets, with one having some saturated fat replaced by carbs, would provide less saturated fat to cell membranes because some of the carb would be used to produce glycogen and fuel brain/stuff. The above paper simply shows that membrane composition differs significantly between diets with different fatty acid ratios, which is an internal link between added saturated fat and membrane changes. See the last line I wrote "although this was not direct addressed..." Is that logic off?

8a3fdcbbec724506de15c14bb6271264

(435)

on September 14, 2011
at 02:09 AM

I thought the body pulls cholesterol from the blood into cell membranes when they become too fluid. Cholesterol gives it rigidity. In fact, isn't this how the conventional wisdom of eating PUFAs to lower cholesterol works? The PUFAs go and make the membrane too fluid and serum cholesterol is "lowered" because it's being pulled into these membranes to give them rigidity (make them less fluid).

7
Medium avatar

on September 13, 2011
at 04:19 PM

The human body very rarely creates fat from carbohydrates as it is an inefficient process. Fats of many lengths can be created via fatty acid synthase as it adds two carbons from acetyl CoA at a time. I suppose that acetyl CoA could originally come from carbs...

What's far more common however is a switch in mitochondrial energy substrate brought about by a glucose-(and amino acid to a lesser extent)induced insulin spike, which inhibits lipolysis via HSL. Under normal fasted circumstances, muscle mitochondria are fueled by our rather large stores of energy as fat, but in the fed state we shift to glucose as a fuel. The net result is that we are releasing and burning less fat from our adipocytes when we eat carbohydrates especially during times of greater activity. It may simply be semantics since the result is the same, but I think it's an important point.

I personally don't believe that saturated fat is a necessary dietary component in the same way that DHA/AA are because we have such huge stores of it that we are releasing constantly into the bloodstream and can manufacture in our cells.

Af1d286f0fd5c3949f59b4edf4d892f5

(18472)

on September 13, 2011
at 04:29 PM

yep. great points. and while sat fats might not be *necessary*, avoiding is also not necessary. also, there are different types of sat fats, of course. dairy is rich in palmitic acid. beef fat is more stearic acid. a lot of people think all sat fat is the same when it's not. i know you know this travis. I'm just adding some thoughts onto your comments.

Medium avatar

(39831)

on September 13, 2011
at 05:22 PM

For a weight stable person, eating a significant portion of your diet as saturated fat is fine, but if one is attempting to decrease body fat, going nuts with a high SFA intake is a big risk.

Medium avatar

(39831)

on September 13, 2011
at 07:31 PM

It's definitely possible to create a net lipolysis with a very high saturated fat intake, but fat is simply so nutrient dense that a leptin-resistant person would not get as much satiety as expected and could easily eat their way to lipogenesis or at least weight stasis. The typical concomitant lowering of carbohydrate intake results in lower insulin (if there aren't hyperinsulinemia problems) and a constant release of FFAs. These must be met with activity to consume them, however, or they will just be recycled back into the adipocytes.

Af1d286f0fd5c3949f59b4edf4d892f5

(18472)

on September 13, 2011
at 07:18 PM

Travis, how come people can lose weight so well on high SFA diets? Not challenging you per se, just wondering.

77877f762c40637911396daa19b53094

(78467)

on September 14, 2011
at 11:20 AM

Fat doesn't influence insulin, carbs does. So, the difference is obviously hormonal. Protein rises ghrelin too, carbs do not. Insulin inhibits lypolisis. There is no other mechanism to control blood sugar apart from insulin, which means, genetically, we don't need redudant pathway as it was never ingested much. External fat comes with vitamins and other stuff. It may also provide more training grounds for immune system cause of greater endotoxin exposure. Carbs on other handm, can only induce AGEs.

4
77877f762c40637911396daa19b53094

(78467)

on September 14, 2011
at 11:34 AM

  • External fat comes with vitamins A,D,E and K2, which are all important. There are other beneficial liposoluable components, like cannabinoids.

  • Simple sugars compete with Ascorbate. High load reduces leucocite phagocytic index by 50% over next 5 hours. Its different when liver is optidosing glucose then what you do when you load it up at once and produces spikes of insulin and blood glucose. Insulin is triggered even by very small amounts of sugar, while beta cells are completely lethargic to fat.

  • On the level of digestive system, carbs produce extra fermentation in the gut. This could and does produce dysbiosis. Extra flatulence is damaging on several levels. On the same level fat makes more endotoxins enter the blood, which probably only provides training grounds for immune system and it is probably kept on higher level.

  • There is no such thing as pure saturated fat in the nature. There are procentages. This means you also ingest DHA/EPA/ALA/MCT/CLA/GLA and friends. All those require resources to be build up in the body and some can not be made by the body. This influences cell membrane and responsiveness to hormones.

  • Liver sparing, as it does de novo lipogenesis. This means it is less capable of doing more important things like toxin clearance. Although the same could be said for gluconeogenesis it must be done anyway. This paper shows that amount of glucose determines lipogenesis 10fold but only a little for gluconeogenesis. So, high fat diet spare liver from working a lot I think. (there are many other papers with the same conclusion btw).

3
100fd85230060e754fc13394eee6d6f1

(18696)

on September 13, 2011
at 07:41 PM

I think the reason that it's better to get saturated fat from dietary fat rather than from dietary carbohydrate has to do with the hormonal effects that come along with the fat or carbs when ingesting them. Even if you can get the fat you need from the carbs, you probably don't want the insulin surge and resulting cascade of inflammatory prostaglandins, the fuel partitioning that favours fat storage, etc, etc. It's not so much the material -- the body tries to get what it needs from what you give it -- but the side-effects.

2
E7a462d6e99fec7e8f0ddda11b34a770

(1638)

on September 13, 2011
at 04:47 PM

+1 for this statement right here:

In the end, you should eat what your body needs, not force your body to try to convert things you don't need into things you do need.

E5c7f14800c5992831f5c70fa746dc5c

(12857)

on September 13, 2011
at 06:17 PM

How come so many vlc's advocate making carbs out of prot?

E7a462d6e99fec7e8f0ddda11b34a770

(1638)

on September 13, 2011
at 06:34 PM

Don't really know - don't really care. (Cliff, imagine I'm saying this in a joking tone of voice WITH a grin so you know I'm not trying to blow you off, OK?) I just think that in general working WITH your body is usually better than working against it.

03fa485bfd54734522755f47a5e6597e

(3944)

on September 14, 2011
at 03:23 PM

Cliff, maybe because it's hard to eat *just* enough carbs to supply one's glucose needs without getting any extra and producing unnecessary insulin and everything that goes with that. If you let your body produce the glucose it wants, presumably it'll produce just enough and no more.

77877f762c40637911396daa19b53094

(78467)

on September 14, 2011
at 02:16 PM

Most people really need coca cola.... meh...

1
F1b82cc7e6d90384ad30007dd6c1b9e3

(1187)

on September 13, 2011
at 08:51 PM

dietary fat is not the same thing as body fat. I think that is what confuses people.

6ec8d30130a6fb274871314533b5536b

(581)

on September 14, 2011
at 04:25 AM

pictures might help...

Answer Question


Get FREE instant access to our
Paleo For Beginners Guide & 15 FREE Recipes!