Does anyone have any science on the metabolic effects of eating carbs and fats in the same meal. I know John Berardi is an advocate of separating carbs and fats so meals are either P+Carbs or P+Fats. He logically argues fat storage is more likely if insulin is elevated, which is what happens when you eat carbs of course, so digesting fats with carbs results in that fat stored as, well, fat.
However, the argument against Berardi’s rationale also makes sense. We know that not only do fats lower the glycemic index of carbs (therefore reducing insulin secretion) but they are also digested slower than carbs. Hence, in a meal with carbs and fats, the carbs are metabolised first, causing a spike in insulin, but in an environment where the fats from the meal haven’t yet been digested and absorbed into the blood-stream. Insulin doesn’t transport those fat molecules because they aren’t available yet (at least from the current meal, but what about the previous meal?)!
I’m looking for research, or even just more anecdotal evidence to help clarify the consequences of eating C+F in the same sitting. I understand that eating a meal heavy in carbs and fats is not at all conducive to fat loss but if you’re reducing meal frequency, it is inevitable.
Carbohydrates are digested faster than proteins and fats so it’s not that carbohydrates are digested “first” it’s just they’re the first ones done. Digestion occurs as a meal, so while fats are slowing down carbohydrate processing carbohydrates are speeding up fat processing. This is why fiber has an association with reducing cholesterol. Fiber inhibits proper digestion of proteins and fats so less dietary saturated fat is absorbed. While this might sound like a good thing if you’re concerned about cholesterol, it also means that less protein and fat soluble nutrients are being absorbed.
Digestion as a whole takes 30+ hours. It takes about 6 - 8 hours just for food to pass through the stomach and small intestine. This means that unless you’re going a significant amount of time between meals your meals are likely to be mixed during digestion for at least some time.
Berardi recently wrote an article about how nutrient timing is dead. This would include meal composition. The fact that we store enough glycogen for 72 hours and digestion takes 30+ hours is clear evidence why; however, there are ways to manipulate these conditions so meal timing does matter.
First things first… I never eat protein or fats with carbohydrates because I want to get as much out of my proteins and fats as possible. This means though that I’m going 12+ hours without eating carbohydrates before I will consume a protein/fat meal. When I eat beef, for example, I’m literally just eating beef. Typically I have beef days where I’ll just consume 4 - 6 lbs of beef for the day.
Secondly this means that if you go beyond the 72 hour glycogen window and induce ketosis it is possible to create physiological difference in energy usage.
A simplistic way of looking at it is:
If you eat a C and F meal and are doing so in caloric surplus your body will likely use what glucose is available from digestion of that meal as an immediate energy source if needed. Once that glucose is used for energy the remaining glucose will be converted into triglycerides and stored in adipose tissue.
It is really the same thing with fats, your body will use what it can for an immediate energy source and start conversion and storage of triglycerides into adipose tissue. The kicker here is, that it is way more efficient for the body to store fats into adipose tissue because no conversion needs to take place.
Ingestion of CHO is usually followed by some amount of insulin secretion and if F is combined with that in a state of caloric surplus it makes for an ideal situation of fat storage.
[quote]schanz_05 wrote:
A simplistic way of looking at it is:
If you eat a C and F meal and are doing so in caloric surplus your body will likely use what glucose is available from digestion of that meal as an immediate energy source if needed.
[/quote]
The body doesn’t use freshly digested glucose as an immediate energy source. Muscles and the liver store glycogen and when they need energy it comes from these stores. If you eat carbohydrates it makes it easier to replenish glycogen, but the body stores enough glycogen for about 3 days. This is one of the reasons why you can exhaust muscle groups. If the glycogen stored in your quads starts running out it doesn’t just sap the glycogen from your biceps. Your biceps will still have sufficient glycogen stores to perform. Glycogen often depletes with intense exercise and in that case fat, lactic acid, and cortisol can all be used as alternative energy substrates.
As a whole low carbohydrate diets have slight advantages over low fat diets because the body is more efficient at utilizing carbohydrates as energy. If you were to account for TEF these would be equal. So it’s not that eating carbohydrates and fats creates any ideal environment for fat storage it’s just more efficient which means more net calories.
[quote]PureNsanity wrote:
[quote]schanz_05 wrote:
A simplistic way of looking at it is:
If you eat a C and F meal and are doing so in caloric surplus your body will likely use what glucose is available from digestion of that meal as an immediate energy source if needed.
[/quote]
The body doesn’t use freshly digested glucose as an immediate energy source. Muscles and the liver store glycogen and when they need energy it comes from these stores. If you eat carbohydrates it makes it easier to replenish glycogen, but the body stores enough glycogen for about 3 days. This is one of the reasons why you can exhaust muscle groups. If the glycogen stored in your quads starts running out it doesn’t just sap the glycogen from your biceps. Your biceps will still have sufficient glycogen stores to perform. Glycogen often depletes with intense exercise and in that case fat, lactic acid, and cortisol can all be used as alternative energy substrates.
As a whole low carbohydrate diets have slight advantages over low fat diets because the body is more efficient at utilizing carbohydrates as energy. If you were to account for TEF these would be equal. So it’s not that eating carbohydrates and fats creates any ideal environment for fat storage it’s just more efficient which means more net calories.[/quote]
Fat and lactic acid are not alternative energy substrates. Muscles will provide for as much of their need as possible with fatty acids before turning to ANY significant glycolysis. Only if ATP demand exceeds replenishment through fatty acids will glycolysis become significant (more than 5% or so). How do you use Hla if you are glycogen depleted? The liver will start to make glucose from glycerol and aminos though. It will even slowly rebuild glycogen in absence of consumed carbs. I think the brain is operating almost immediately off of blood glucose.
And I don’t agree on carbs versus fat. If you wake up fasted and eat carbs, your body will not mobilize fat to maintain workload, and glycogen will get tapped into (and protein) sooner. The insulin from the carbs will protect fat stores. If you wake up and eat FAT, well you have to burn the fat you ate, but your body will spare glycogen, and muscle protein.
If you are not glycogen depleted at all, basically all the carbs you eat have to get converted to fatty acids anyway, but the other advantage in reducing carbs is that carbs don’t contain any essential nutrients that lead to deficiencies. Fats contain most of the nutrients that people become deficient in when they reduce calories.
[quote]schanz_05 wrote:
A simplistic way of looking at it is:
If you eat a C and F meal and are doing so in caloric surplus your body will likely use what glucose is available from digestion of that meal as an immediate energy source if needed. Once that glucose is used for energy the remaining glucose will be converted into triglycerides and stored in adipose tissue.
It is really the same thing with fats, your body will use what it can for an immediate energy source and start conversion and storage of triglycerides into adipose tissue. The kicker here is, that it is way more efficient for the body to store fats into adipose tissue because no conversion needs to take place.
Ingestion of CHO is usually followed by some amount of insulin secretion and if F is combined with that in a state of caloric surplus it makes for an ideal situation of fat storage.
[/quote]
Your body will use the carbs to replenish glycogen, and then turn the rest into fatty acids. For the most part, combining fat and carbs together will tend to make the carbs act like more fat anyway, except up to the level that the brain is going to use in a short period of time 2-3 hours, after.
Most of your meals should have more fat than anything else, and if you have some carbs with the fat, it really makes little difference. Your blood sugar is going to be very stable. Your protein and calories will last quite a while to prevent muscle breakdown. And don’t forget people that pure protein ends up stimulating insulin just like carbs on a lesser scale. So eat some carbs with protein and a typically 40-60% fat meal.
IF you are glycogen depleted from training though, that is when you do not want fat, because it will slow down glycogen buildup and it won’t top off completely. There SHOULD be low carb, high fat meals, and there may be a need for high carb, virtually zero fat meals.
[quote]mertdawg wrote:
[quote]schanz_05 wrote:
A simplistic way of looking at it is:
If you eat a C and F meal and are doing so in caloric surplus your body will likely use what glucose is available from digestion of that meal as an immediate energy source if needed. Once that glucose is used for energy the remaining glucose will be converted into triglycerides and stored in adipose tissue.
It is really the same thing with fats, your body will use what it can for an immediate energy source and start conversion and storage of triglycerides into adipose tissue. The kicker here is, that it is way more efficient for the body to store fats into adipose tissue because no conversion needs to take place.
Ingestion of CHO is usually followed by some amount of insulin secretion and if F is combined with that in a state of caloric surplus it makes for an ideal situation of fat storage.
[/quote]
Your body will use the carbs to replenish glycogen, and then turn the rest into fatty acids. For the most part, combining fat and carbs together will tend to make the carbs act like more fat anyway, except up to the level that the brain is going to use in a short period of time 2-3 hours, after. [/quote]
Yes, assuming you are glycogen depleted, and I was speaking in terms of caloric surplus where you probably would not be glycogen depleted. I still think the act of having an insulin presence along with fatty acids in the blood is creating an idealistic scenario for fat storage due to the ease of storage.
[quote]PureNsanity wrote:
[quote]schanz_05 wrote:
A simplistic way of looking at it is:
If you eat a C and F meal and are doing so in caloric surplus your body will likely use what glucose is available from digestion of that meal as an immediate energy source if needed.
[/quote]
The body doesn’t use freshly digested glucose as an immediate energy source. Muscles and the liver store glycogen and when they need energy it comes from these stores. If you eat carbohydrates it makes it easier to replenish glycogen, but the body stores enough glycogen for about 3 days. This is one of the reasons why you can exhaust muscle groups. If the glycogen stored in your quads starts running out it doesn’t just sap the glycogen from your biceps. Your biceps will still have sufficient glycogen stores to perform. Glycogen often depletes with intense exercise and in that case fat, lactic acid, and cortisol can all be used as alternative energy substrates.
As a whole low carbohydrate diets have slight advantages over low fat diets because the body is more efficient at utilizing carbohydrates as energy. If you were to account for TEF these would be equal. So it’s not that eating carbohydrates and fats creates any ideal environment for fat storage it’s just more efficient which means more net calories.[/quote]
I wouldn’t say the body is more efficient at utilizing one energy substrate over the other. There is just preferential usage of one substrate over the other, and it also depends on state the body it is (brain using glucose, muscles using fatty acids at rest, or glucose during anaerobic exercise, etc).
[quote]schanz_05 wrote:
I wouldn’t say the body is more efficient at utilizing one energy substrate over the other. There is just preferential usage of one substrate over the other, and it also depends on state the body it is (brain using glucose, muscles using fatty acids at rest, or glucose during anaerobic exercise, etc).[/quote]
I completely agree that some organs/processes have preferential usage. I was actually reading a study about the heart and energy substrate usage. One of the things it discussed was how inefficient the heart was at using fatty acids to replenish it’s ATP, but it has to turn over it’s ATP 6 to 8 times a minute so it uses almost everything.
There is definitely an efficiency consideration with energy substrate usage. For example with protein the process of gluconeogenesis must occur which of course takes energy. The more energy it takes to convert protein into usable energy the less efficient of an energy source it is.
[quote]PureNsanity wrote:
[quote]schanz_05 wrote:
I wouldn’t say the body is more efficient at utilizing one energy substrate over the other. There is just preferential usage of one substrate over the other, and it also depends on state the body it is (brain using glucose, muscles using fatty acids at rest, or glucose during anaerobic exercise, etc).[/quote]
I completely agree that some organs/processes have preferential usage. I was actually reading a study about the heart and energy substrate usage. One of the things it discussed was how inefficient the heart was at using fatty acids to replenish it’s ATP, but it has to turn over it’s ATP 6 to 8 times a minute so it uses almost everything.
There is definitely an efficiency consideration with energy substrate usage. For example with protein the process of gluconeogenesis must occur which of course takes energy. The more energy it takes to convert protein into usable energy the less efficient of an energy source it is.
[/quote]
I understand what you are saying. I was speaking of your comparison of CHO being utilized more efficient than F. That is more a matter of preference between the state of the body, and what organ/system is using the substrate. Protein as an energy source is always going to be inefficient because it has to undergo conversion like you talked about (gluconeogenesis).
[quote]PureNsanity wrote:
[quote]mertdawg wrote:
Fat and lactic acid are not alternative energy substrates.
[/quote]
Fat reference Metabolism of substrates: energy substrate metabolism during exercise and as modified by training - PubMed.
Lactic acid reference http://jp.physoc.org/content/582/3/899.full.pdf.
[/quote]
The first article won’t come up. The second one still begs the question: Where does the lactate come from? And doesn’t say anything to show me that its not from glycolysis. So lactate gets used, but it had to come from carbs at some point. No carbs means no lactate.
[quote]mertdawg wrote:
[
The first article won’t come up. The second one still begs the question: Where does the lactate come from? And doesn’t say anything to show me that its not from glycolysis. So lactate gets used, but it had to come from carbs at some point. No carbs means no lactate. [/quote]
Remove the period from the end - not sure why the period got included.
http://www.ncbi.nlm.nih.gov/...pubmed/3967777
Lactic acid is produced from pyruvate as far as I’m aware. Think about this… If you were fasting in full ketosis and you were exercising would you produce significantly less lactic acid?
[quote]PureNsanity wrote:
[quote]mertdawg wrote:
[
The first article won’t come up. The second one still begs the question: Where does the lactate come from? And doesn’t say anything to show me that its not from glycolysis. So lactate gets used, but it had to come from carbs at some point. No carbs means no lactate. [/quote]
Remove the period from the end - not sure why the period got included.
http://www.ncbi.nlm.nih.gov/...pubmed/3967777
Lactic acid is produced from pyruvate as far as I’m aware. Think about this… If you were fasting in full ketosis and you were exercising would you produce significantly less lactic acid?
[/quote]
Pyruvate comes from carbs. I am pretty sure that fatty acids enter the Kreb’s cycle past the point of Pyruvate, but I’ll double check. In Ketosis, you are making carbs from the amino acids, as well as from fat, so those carbs are getting turned into pyruvate, and then lactate.
I do not believe that their is a way to get to pyruvate or lactate from fat or protein without turning them into glucose first.
And, well, I think you would make much less lactate in Ketosis. Not only is there only minimal carbs available to turn into lactate, but also you have a lowered blood pH from the ketones and so your tolerance for lactic acid is lower.
Yep, fats enter the Kreb’s cycle as Acetyl-CoA which is already a step beyond pyruvate.
So I have to hold that the only source of pyruvate and lactate is carbs. Lactate/Pyruvate is a product of Glycolysis so its not an alternative.
[quote]mertdawg wrote:
Pyruvate comes from carbs. I am pretty sure that fatty acids enter the Kreb’s cycle past the point of Pyruvate, but I’ll double check. In Ketosis, you are making carbs from the amino acids, as well as from fat, so those carbs are getting turned into pyruvate, and then lactate.
I do not believe that their is a way to get to pyruvate or lactate from fat or protein without turning them into glucose first.
And, well, I think you would make much less lactate in Ketosis. Not only is there only minimal carbs available to turn into lactate, but also you have a lowered blood pH from the ketones and so your tolerance for lactic acid is lower. [/quote]
Ketogenesis doesn’t produce glucose although lipolysis can produce glycerol. Ketogenesis produces the ketone bodies acetoacetate and β-hydroxybutyrate which are used for energy. Ketogenesis also does not involve breaking down amino acids either that’s gluconeogenesis. It’s also specifically why I used the “fasting” example instead of a ketogenic diet example where protein could still be supporting gluconeogenesis.
Do you have any sources to support reduced lactic acid production in ketosis?
[quote]PureNsanity wrote:
[quote]mertdawg wrote:
Pyruvate comes from carbs. I am pretty sure that fatty acids enter the Kreb’s cycle past the point of Pyruvate, but I’ll double check. In Ketosis, you are making carbs from the amino acids, as well as from fat, so those carbs are getting turned into pyruvate, and then lactate.
I do not believe that their is a way to get to pyruvate or lactate from fat or protein without turning them into glucose first.
And, well, I think you would make much less lactate in Ketosis. Not only is there only minimal carbs available to turn into lactate, but also you have a lowered blood pH from the ketones and so your tolerance for lactic acid is lower. [/quote]
Ketogenesis doesn’t produce glucose although lipolysis can produce glycerol. Ketogenesis produces the ketone bodies acetoacetate and Ã?²-hydroxybutyrate which are used for energy. Ketogenesis also does not involve breaking down amino acids either that’s gluconeogenesis. It’s also specifically why I used the “fasting” example instead of a ketogenic diet example where protein could still be supporting gluconeogenesis.
Do you have any sources to support reduced lactic acid production in ketosis?
[/quote]
OK I understand calling fat an alternative source of energy. When glucose is low, triglycerides are sent to cells to increase the amount of beta oxidation. However it is important to realize that in muscles fatty acids are used preferrentially even when glycogen reserves are full.
Ketosis and gluconeogenesis from amino acids tend to happen at the same time, when carbs are low, but the BCAAs tend to get made into glucose while the others tend to make ketones.
Do you have any source that shows lactic acid can come from any source other than glucose?
paleohacks.com/questions/120969/keto-and-lactic-acid.html
On a ketogenic diet the muscles produce much less lactate than on a mixed diet.
Lactic acid is a product of carb metabolism. Ketones are the result of diminished carbs!