Extra carbs do not get converted into fat.
darkchocthunda
Posts: 20 Member
There's a very entrenched and long running bit of misinformation about what your body does with extra food. Most people say that extra protein and carbs gets turned into fat, but that is not the case at all.
The conversion of carbohydrates into fat is a process called de novo lipogenesis (de novo = new, lipo = fat, genesis = making), The human body is poor and inefficient at this, it's only animals like cows, deer and pigs that are good at doing it.
What really happens is that when you eat, your body has a specific order to digest each macronutrient. This order is based on the rate at which the macro can be broken down and just plain preference. Carbs, even complex carbs, are relatively quick to digest and your body breaks them down first. Protein is slow digesting, and breaks down towards the end. Fat is in the middle but your body prefers digesting carbs first.
So say you ate a lot of food one day. You repeatedly over eat at each meal. What happens is that your body immediately starts on the carbs. But because you ate more than you needed, it never got a chance to finish digesting the carbs in time to work on the fat before the next meal. So what happens is that the extra fat is stored as adipose tissue until your body is done with the other macronutrients.
There's no conversion of carbs to fat, or at least not a lot of it.
The conversion of carbohydrates into fat is a process called de novo lipogenesis (de novo = new, lipo = fat, genesis = making), The human body is poor and inefficient at this, it's only animals like cows, deer and pigs that are good at doing it.
What really happens is that when you eat, your body has a specific order to digest each macronutrient. This order is based on the rate at which the macro can be broken down and just plain preference. Carbs, even complex carbs, are relatively quick to digest and your body breaks them down first. Protein is slow digesting, and breaks down towards the end. Fat is in the middle but your body prefers digesting carbs first.
So say you ate a lot of food one day. You repeatedly over eat at each meal. What happens is that your body immediately starts on the carbs. But because you ate more than you needed, it never got a chance to finish digesting the carbs in time to work on the fat before the next meal. So what happens is that the extra fat is stored as adipose tissue until your body is done with the other macronutrients.
There's no conversion of carbs to fat, or at least not a lot of it.
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Fat is the slowest digesting macronutrient: carbs first, then protein, then fat. This also is false, as I could eat at maintenance early in the day, then if I ate a carb based only meal before I went to bed that was past my maintenance, it would still be converted to fat. Regardless of the macronutrient, the excess of calories acquired from the carb or whatever macro you eat will turn to fat if it puts you in a surplus.0
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I have no idea why anyone would think this could matter on a practical level. If you consume a calorie surplus, regardless of macronutrient content, you will have a net increase of adipose tissue at the end of the day. If you consume a calorie deficit, you will have a net decrease of adipose tissue at the end of the day. Pretty simple, don't over complicate it.0
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And if you keep your carbs low your body burns fat once its through the carbs
None of this matters if you aren't eating at a calorie deficit.0 -
Who cares. Eat at calorie deficit = lose weight. Simple.0
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Are you considering the role of insulin in fat storage? Carbs and somewhat less, protein, induce the body to produce insulin. It seems like insulin is basically REQUIRED in order to put on body fat.
Looking at pictures of type 1 diabetics in the age before insulin was discovered and produced is educational.0 -
darkchocthunda wrote: »There's no conversion of carbs to fat, or at least not a lot of it.
depends on a number of variables.
I agree that the body tries to oxidise incoming glucose first, to avoid it accumulating in the bloodstream, and shuttles it off into glycogen reserves second, but if it's coming in too fast or the glycogen tanks are full then it's going into fat as there ain't no alternative.
Several lines of evidence point to endogenously produced palmitoleic acid (i.e., cis-16:1n-7) as being associated with dietary carbohydrate intake.
To get to substantial DNL requires carbohydrate overfeeding ie eating more carbs than TDEE.
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Carbs drive insulin, high insulin stores fat and prevents burning of fat. Excess carbs give you the "spare tire". Period.0
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Pollywog_la wrote: »Are you considering the role of insulin in fat storage? Carbs and somewhat less, protein, induce the body to produce insulin. It seems like insulin is basically REQUIRED in order to put on body fat.
Looking at pictures of type 1 diabetics in the age before insulin was discovered and produced is educational.
Dietary fat does not need insulin to be stored as fat.0 -
Pollywog_la wrote: »Are you considering the role of insulin in fat storage? Carbs and somewhat less, protein, induce the body to produce insulin. It seems like insulin is basically REQUIRED in order to put on body fat..
Nope
MYTH: Carbohydrate Drives Insulin, Which Drives Fat Storage
FACT: Your Body Can Synthesize and Store Fat Even When Insulin Is Low
One of the biggest misconceptions regarding insulin is that it's needed for fat storage. It isn't. Your body has ways to store and retain fat even when insulin is low. For example, there is an enzyme in your fat cells called hormone-sensitive lipase (HSL). HSL helps break down fat. Insulin suppresses the activity of HSL, and thus suppresses the breakdown of fat. This has caused people to point fingers at carbohydrate for causing fat gain.
However, fat will also suppress HSL even when insulin levels are low. This means you will be unable to lose fat even when carbohydrate intake is low, if you are overeating on calories. If you ate no carbohydrate but 5,000 calories of fat, you would still be unable to lose fat even though insulin would not be elevated. This would be because the high fat intake would suppress HSL. This also means that, if you're on a low carbohydrate diet, you still need to eat less calories than you expend to lose weight.
http://weightology.net/weightologyweekly/index.php/free-content/free-content/volume-1-issue-7-insulin-and-thinking-better/insulin-an-undeserved-bad-reputation/Looking at pictures of type 1 diabetics in the age before insulin was discovered and produced is educational.
No, it really isn't
MYTH: Since diabetics who inject insulin gain weight, this means that insulin is the reason for weight gain in non-diabetics
FACT: Amylin is co-secreted with insulin in non-diabetics; amylin has appetite suppressant and lipolytic effects
I would like to thank Dr. Stephan Guyenet for this information. I had known about amylin but hadn't looked into it in any great detail. Amylin is a hormone that is secreted by your pancreas at the same time as insulin. Amylin decreases appetite, and also stimulates lipolysis (the breakdown of fat into fatty acids).
Type 1 diabetics do not produce amylin, and amylin secretion is impaired in type 2 diabetics. Pramlintide, a drug that mimics the effects of amylin, has been found to produce weight loss in diabetics.
This information demonstrates that the effects of insulin injection in a diabetic cannot be compared to the effects of physiological changes in insulin in a non-diabetic, yet many people erroneously make this comparison as if they are similar.
http://weightology.net/weightologyweekly/index.php/free-content/free-content/volume-1-issue-10-insulin-physical-activity-and-weight-regain/insulin-an-undeserved-bad-reputation-part-2/
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So you are saying carbs do not get stored as fat, or at least not much if you are eating other macros, even when you over eat at each meal? I don't agree.
Your body works hard to keep your body's blood glucose stable, and when the glucose levels are rising it needs to clear glucose from your blood. If there is excess glucose that can't be used or stored it is going to become fat.
Feltham did two 21 day overeating challenges. In one challenge he ate higher carb diet and in another he ate lower carb but higher fat. Both were 5000 kcal per day and had the same activity levels.
In the higher carb diet he gained about 7 kg and his waist expanded noticeably. http://live.smashthefat.com/5000-calorie-carb-challenge-day-21/
In the higher fat challenge he gained 1.3 kg and his waist circumference actually shrank. http://live.smashthefat.com/5000-calorie-challenge-day-21/
Not a scientific study but an interesting n=1 experiment. If carbs are not stored as fat, he should have had different results.0 -
So you are saying carbs do not get stored as fat, or at least not much if you are eating other macros, even when you over eat at each meal? I don't agree.
Your body works hard to keep your body's blood glucose stable, and when the glucose levels are rising it needs to clear glucose from your blood. If there is excess glucose that can't be used or stored it is going to become fat.
Feltham did two 21 day overeating challenges. In one challenge he ate higher carb diet and in another he ate lower carb but higher fat. Both were 5000 kcal per day and had the same activity levels.
In the higher carb diet he gained about 7 kg and his waist expanded noticeably. http://live.smashthefat.com/5000-calorie-carb-challenge-day-21/
In the higher fat challenge he gained 1.3 kg and his waist circumference actually shrank. http://live.smashthefat.com/5000-calorie-challenge-day-21/
Not a scientific study but an interesting n=1 experiment. If carbs are not stored as fat, he should have had different results.
I take water weight for 500, Alex.0 -
I'll take actual science over a blogger's self-reported "experiment"
De novo lipogenesis in humans: metabolic and regulatory aspects.
Hellerstein MK1.
Author information
Abstract
The enzymatic pathway for converting dietary carbohydrate (CHO) into fat, or de novo lipogenesis (DNL), is present in humans, whereas the capacity to convert fats into CHO does not exist. Here, the quantitative importance of DNL in humans is reviewed, focusing on the response to increased intake of dietary CHO. Eucaloric replacement of dietary fat by CHO does not induce hepatic DNL to any substantial degree. Similarly, addition of CHO to a mixed diet does not increase hepatic DNL to quantitatively important levels, as long as CHO energy intake remains less than total energy expenditure (TEE). Instead, dietary CHO replaces fat in the whole-body fuel mixture, even in the post-absorptive state. Body fat is thereby accrued, but the pathway of DNL is not traversed; instead, a coordinated set of metabolic adaptations, including resistance of hepatic glucose production to suppression by insulin, occurs that allows CHO oxidation to increase and match CHO intake. Only when CHO energy intake exceeds TEE does DNL in liver or adipose tissue contribute significantly to the whole-body energy economy. It is concluded that DNL is not the pathway of first resort for added dietary CHO, in humans. Under most dietary conditions, the two major macronutrient energy sources (CHO and fat) are therefore not interconvertible currencies; CHO and fat have independent, though interacting, economies and independent regulation. The metabolic mechanisms and physiologic implications of the functional block between CHO and fat in humans are discussed, but require further investigation.
http://www.ncbi.nlm.nih.gov/pubmed/10365981
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Eating excess calories causes a physical reaction called "de lardo gluteus", fat goes to your butt.
Anything beyond that is over complicated ramblings.0 -
darkchocthunda wrote: »...What really happens is that when you eat, your body has a specific order to digest each macronutrient. This order is based on the rate at which the macro can be broken down and just plain preference. Carbs, even complex carbs, are relatively quick to digest and your body breaks them down first. Protein is slow digesting, and breaks down towards the end. Fat is in the middle but your body prefers digesting carbs first...
I also don't think it's quite that simple. Monosaccharides, Disaccharides and Polysaccharides are not all metabolized at equal rates, and all proteins are not "slow digesting". Whey protein is relatively fast, for example, while casein takes longer to digest and enter the bloodstream.
It's also not true that the body compartmentalizes digestion so neatly. There are various enzymes and processes involved in the digestive process and they are all working simultaneously. Proteins and fats don't just sit there waiting in line while the body goes through carbohydrates first.
It is correct that de novo lipogenesis is an inefficient process in humans, as noted in the study posted above by @FunkyTobias - but the pathway does exist, especially in a surplus.0 -
FunkyTobias wrote: »Pollywog_la wrote: »Looking at pictures of type 1 diabetics in the age before insulin was discovered and produced is educational.
No, it really isn't
MYTH: Since diabetics who inject insulin gain weight, this means that insulin is the reason for weight gain in non-diabetics
FACT: Amylin is co-secreted with insulin in non-diabetics; amylin has appetite suppressant and lipolytic effects
I would like to thank Dr. Stephan Guyenet for this information. I had known about amylin but hadn't looked into it in any great detail. Amylin is a hormone that is secreted by your pancreas at the same time as insulin. Amylin decreases appetite, and also stimulates lipolysis (the breakdown of fat into fatty acids).
Type 1 diabetics do not produce amylin, and amylin secretion is impaired in type 2 diabetics. Pramlintide, a drug that mimics the effects of amylin, has been found to produce weight loss in diabetics.
This information demonstrates that the effects of insulin injection in a diabetic cannot be compared to the effects of physiological changes in insulin in a non-diabetic, yet many people erroneously make this comparison as if they are similar.
http://weightology.net/weightologyweekly/index.php/free-content/free-content/volume-1-issue-10-insulin-physical-activity-and-weight-regain/insulin-an-undeserved-bad-reputation-part-2/
Don't forget that a lot of the weight gained with initial insulin therapy is related to glycogen and water being replenished and the body trying to get itself out of the big mess it made (to put it simply). There's also the fact that diabetics might be maintaining their weight by eating in a calorie surplus (because glucose is filtered through the kidneys if BG is above renal threshold -about 180mg/dL) and subsequently gain weight as their BG control improves (this is often why one of the "side effects" of insulin pump therapy is weight gain, because BG control often improves with it).
I think I gained 15 pounds in 6-7 weeks upon starting insulin, but the undiagnosed diabetes caused me to lose 55 pounds in roughly three months (I was losing about a pound per day in the week leading up to my DKA and diagnosis).
The current research on amylin is quite interesting. I'm trying to remember its effect on glycemic control, but doesn't it also help delay stomach emptying? If stomach emptying isn't delayed, food rapidly enters the small intestine for absorption, which might cause a very sudden and rapid BG spike (because current insulin analogs only start working 15-30 minutes after injection and peak at the 45-90 minute mark) and hunger.
In terms of dietary fat slowing gastric emptying (AKA: the pizza effect), wouldn't following a higher-fat diet help diabetics account for the insufficient secretion or absence of amylin? The fat would then slow down gastric emptying, promote satiety (compared to a high-carb low-fat diet), and cause less crazy BG spikes. I've noticed in my own BG logs that I'm much more stable if I get ample dietary fat/protein, and that moderate fat/protein meals typically don't require me to pre-inject my mealtime insulin 30 minutes in advance while still keeping my BG spikes below 150 (90% of the time).0 -
Working2BLean wrote: »Eating excess calories causes a physical reaction called "de lardo gluteus", fat goes to your butt.
Anything beyond that is over complicated ramblings.
997 points
X2 for your avi0 -
Informative thread, thanks to he contributors. This is why I like MFP, I learn more all the time.0
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FunkyTobias wrote: »I'll take actual science over a blogger's self-reported "experiment"
De novo lipogenesis in humans: metabolic and regulatory aspects.
Hellerstein
http://www.ncbi.nlm.nih.gov/pubmed/10365981
Some more up to date work :
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3151688/ "We have shown that the differentiating human adipocyte is capable of synthesizing all the fatty acids it needs for maturation de novo from nonlipid precursors."
and a more up to date review :
http://www.sciencedirect.com/science/article/pii/S2212877815000599 "3.4. DNL is an important mechanism for glucose disposal" and subsequent sections0 -
FunkyTobias wrote: »I'll take actual science over a blogger's self-reported "experiment"
De novo lipogenesis in humans: metabolic and regulatory aspects.
Hellerstein
http://www.ncbi.nlm.nih.gov/pubmed/10365981
Some more up to date work :
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3151688/ "We have shown that the differentiating human adipocyte is capable of synthesizing all the fatty acids it needs for maturation de novo from nonlipid precursors."
In vitro
In mice
and a more up to date review :
http://www.sciencedirect.com/science/article/pii/S2212877815000599 "3.4. DNL is an important mechanism for glucose disposal" and subsequent sections
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stevencloser wrote: »So you are saying carbs do not get stored as fat, or at least not much if you are eating other macros, even when you over eat at each meal? I don't agree.
Your body works hard to keep your body's blood glucose stable, and when the glucose levels are rising it needs to clear glucose from your blood. If there is excess glucose that can't be used or stored it is going to become fat.
Feltham did two 21 day overeating challenges. In one challenge he ate higher carb diet and in another he ate lower carb but higher fat. Both were 5000 kcal per day and had the same activity levels.
In the higher carb diet he gained about 7 kg and his waist expanded noticeably. http://live.smashthefat.com/5000-calorie-carb-challenge-day-21/
In the higher fat challenge he gained 1.3 kg and his waist circumference actually shrank. http://live.smashthefat.com/5000-calorie-challenge-day-21/
Not a scientific study but an interesting n=1 experiment. If carbs are not stored as fat, he should have had different results.
I take water weight for 500, Alex.
ding ding ding...we have a winner.
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