What does the body use for energy?

[Southern Cross]

I have read many different things since joining AR. I have read that I should do weight training first then cardio. I have read that I should limit cardio to 45 minutes or less because I run the risk of burning lean muscles. I have read that the first minutes of cardio taps into you carbohydrates anything over that will tap into your store fats.

What I would like to know is what is the order the body burns carbs, fats, and proteins while doing anarobic activities?

What is the order the body burns carbs, fats, and proteins while doing aerobic activties?

I understand that it is possible that the order may vary depending upon my physical makeup so here are my stats:

5'7
192
17% bf

Thanks!

[painintheazz]

This is going to be very dependent upon your body, but most it goes carbs first until glycogen stores are depleated. Then fat, but this is as long as what you are doing isn't intense enough to warrent burning muscle. I think anything above 70% MHR (when blood sugar is low/depleated), is where your body can't convert fat stores quick enough and starts to get into your muscle and converts muscle protein into glycogen. (This also depends on how conditioned of an athlete you are.) Hope this helps a little.

Pain

[yellows2k]

I think in a basic, general sense, whatever is easily and readily available for your body to use.

It also depends on many factors such as diet. If you only eat like 1 meal a day, your body goes into starvation mode, so it will more likely use the muscles before resorting to fat. Everybody is different, and learning what is optimal for your body is key in maintaining a healthy lifestyle

[painintheazz]

Very true, what I posted is general for a healthy adult that consumes a normal diet, with 5 or 6 meals.

Pain

[Southern Cross]

Originally posted by painintheazz
This is going to be very dependent upon your body, but most it goes carbs first until glycogen stores are depleated. Then fat, but this is as long as what you are doing isn't intense enough to warrent burning muscle. I think anything above 70% MHR (when blood sugar is low/depleated), is where your body can't convert fat stores quick enough and starts to get into your muscle and converts muscle <a href="http://www.allsportsnutrition.com/listproducts.php?style=category&value=PROTEIN" target="_blank">protein</a> into glycogen. (This also depends on how conditioned of an athlete you are.) Hope this helps a little.

Pain

Pain, what is MHR?

[yellows2k]

Maximum Heart Rate

[Warrior]

A good analogy that I heard once is to think of your bodies main 3 sources of energy as fuel for a fire. Carbs (and stored Glycogen) and Protein (and muscle tissue) are like tissue paper. Your body will readily burn them with no problem. Fats (and stored fat) are like starting a log on fire...

How to burn the most fat and spare the most muscle is a big topic...

[Farmer]

Hopefully this will help bro....there are 4 systems that your body goes through to make energy..

1st- Phosphagen system (Fuel source is ATP): It's the first and last's about 30 seconds
2nd- Fast glycolysis (Fuel source is Carbs):used up until about 5 minutes
3rd- Slow Glycolysis (Fuel source is Carbs/fat at about a 50/50 ratio): used up until 20 mins
4th Oxidative system (Fuel source is Fat): used 20 mins+

and anything after 2 hours of aerobic activity you'll start burning BCAA's for energy. The way I look at this whole thing is similar to gears in a car. You always have to start in 1st hear...and you always start with the phosphagen system for energy, whether you are weightlifting or getting the mail. Then you shift into 2nd gear after a certain period of time...then you shift to third..and so on..

Hope this helps bro...

Peace

[daem]

farmer, great info...bump

[Farmer]

Thanks daem, I'm actually learning things in school now

peace

[painintheazz]

Originally posted by Farmer
Thanks daem, I'm actually learning things in school now

peace

Your not supposed to learn in school, you idiot....

Pain

[Southern Cross]

Originally posted by Farmer
Hopefully this will help bro....there are 4 systems that your body goes through to make energy..

1st- Phosphagen system (Fuel source is ATP): It's the first and last's about 30 seconds
2nd- Fast glycolysis (Fuel source is Carbs):used up until about 5 minutes
3rd- Slow Glycolysis (Fuel source is Carbs/fat at about a 50/50 ratio): used up until 20 mins
4th Oxidative system (Fuel source is Fat): used 20 mins+

and anything after 2 hours of aerobic activity you'll start burning BCAA's for energy. The way I look at this whole thing is similar to gears in a car. You always have to start in 1st hear...and you always start with the phosphagen system for energy, whether you are weightlifting or getting the mail. Then you shift into 2nd gear after a certain period of time...then you shift to third..and so on..

Hope this helps bro...

Peace

Farmer, so what you are saying is if I keep my workouts short of 2 hours I should burn only ATP, Carbs, and fat. Correct?

[painintheazz]

IMO, I think 2 hours is pretty long and you would start dipping into muscle. Depends on the intensity of the exercise though. But after an intense lifting session (45mins) and then doing cardio for 1 hour and 15 mins I think you would burn some muscle. I haven't seen any research on this but from my own body that is what I feel.

Pain

[Farmer]

Originally posted by Southern Cross


Farmer, so what you are saying is if I keep my workouts short of 2 hours I should burn only ATP, Carbs, and fat. Correct?

For the most part yes...although, listen to your body and find what works best for you. The information I gave is what I have learned from my personal training and A&P classes..which gives you the guidelines on how the body uses energy. Now hypothetically speaking if you were carb depleteing (didn't mean to rhyme ) then that would change things a bit...I don't know what your trying to do as far as your workouts are concerned. But, if you are looking to cut fat, my suggestion is and what I do is... lower your carbs and up the protein and I do my cardio first thing in the morning after 2 scoops of protein in water..and do 45 minutes of cardio at around 55-60% of MHR and it worked very well last time, I dropped 15% BF in 3 months and lost 15 lbs...hopefully that helped if not holla' back...


Peace

[RealMenBench]

the only part of this thread that isn't entirely correct is the part about a 2 hour workout getting into using muscle for energy ......

that's a yes and no ...... if you workout for 3 hours, you aren't going to "burn your muscles" for that last hour .... what you are doing though, is depleting your readily available energy sources and then causing your body to trigger an "emergency repair" response..... this happens after your workout, and it is then that you use the proteins for fuel rather than using them to build muscles ...... it's called catabolism

If you've noticed, all cardio workouts target you to go at least 20 mins ... thats for a reason, as you must first use the ATP and Glycogen in order to get to the fat ... a low-mod to moderate intensity for 20-45 mins is optimal for fat burning .... but you have to "switch gears" as was stated earlier in the thread ..... think about it this way ...

which car burns more gas ? the one that slowly starts at the red light and goes 30 mph to the next one, or the car that speeds off and abruptly stops at the next light ?

[painintheazz]

Originally posted by RealMenBench
the only part of this thread that isn't entirely correct is the part about a 2 hour workout getting into using muscle for energy ......

that's a yes and no ...... if you workout for 3 hours, you aren't going to "burn your muscles" for that last hour .... what you are doing though, is depleting your readily available energy sources and then causing your body to trigger an "emergency repair" response..... this happens after your workout, and it is then that you use the <a href="http://www.allsportsnutrition.com/listproducts.php?style=category&value=PROTEIN" target="_blank">protein</a>s for fuel rather than using them to build muscles ...... it's called catabolism

If you've noticed, all cardio workouts target you to go at least 20 mins ... thats for a reason, as you must first use the ATP and Glycogen in order to get to the fat ... a low-mod to moderate intensity for 20-45 mins is optimal for fat burning .... but you have to "switch gears" as was stated earlier in the thread ..... think about it this way ...

which car burns more gas ? the one that slowly starts at the red light and goes 30 mph to the next one, or the car that speeds off and abruptly stops at the next light ?

True, it all depends on what you are doing.

Pain

[Farmer]

Originally posted by RealMenBench
the only part of this thread that isn't entirely correct is the part about a 2 hour workout getting into using muscle for energy ......

that's a yes and no ...... if you workout for 3 hours, you aren't going to "burn your muscles" for that last hour .... what you are doing though, is depleting your readily available energy sources and then causing your body to trigger an "emergency repair" response..... this happens after your workout, and it is then that you use the proteins for fuel rather than using them to build muscles ...... it's called catabolism

True, it's not muscle being burned but protein being used for energy, which as you said is catabolism. When the body starts using protein for energy it's because it no longer has adequate glycogen to pull from. So it uses protein in a process called Gluconeogensis where the protein is essentially made into glucose to use for energy. Which is the process everyone refers to when they are talking about burning muscle or what not. This is turning into a really informative thread, which is good!


Peace

[BrokenBricks]

"True, it's not muscle being burned but protein being used for energy, which as you said is catabolism. When the body starts using protein for energy it's because it no longer has adequate glycogen to pull from. So it uses protein in a process called Gluconeogensis where the protein is essentially made into glucose to use for energy. Which is the process everyone refers to when they are talking about burning muscle or what not. This is turning into a really informative thread, which is good!"

I know you mean well farmer, but this is not acurate. Nor is the idea of specific "gears" in your metabolism.

Look in your text book at the metabolism of glucose. It goes through glycolosis, becomes pyruvate, then acetyl coa, then goes thorugh the TCA cycle. When protien are borken into their constituent AA, they either go directly into the TCA (as one of the eight intermediates) or they become acetylCoA. The point is that why would the body turn protien into glucose if it was looking for energy. That would be incredibly inefficent. It would become AcetylCoa, then through gluconeogenisis to glucose then what? Through glycolosis to Acetyl coa again! then the TCA cycle and oxidative phosphorilation. protien only goes through gluconeogenisis when your body has excess energy, but it is not in the correct form ( glucose for brain, is the main purpose of gluconeogenisis).

And as far as the gear therory, the graph you are looking at is showing you the relative ease of access of different energy stores. ATP then NADH<FADH2 then glucose, glycogen ect. And it is true that those energy stores are used in a definite order for most levels of activity. But as pain correctly said in fewer words....Burning fat is a long proccess, you have big long molecules that have to be expelled from your gut, float to your leg muslces and get absorbed, then broken down into tiny peicesby B-oxidation , then sent though the TCA cycle then though the mitocondira, then the ox-phos chain, blah blah blah. It takes time, which is cool, if you are at about 60-70% or yor MHR. But there is a ceiling of calories that can be liberatd from fat in a given time period. If you demand more than that, your body cannot wait and will burn the protien that is in the very cells that need it. SO the gear theory only works at low enough intensity.

But dont stop trying to learn all this. You are doing great by learning the true sceince behind your body and a million magzines dont have a fraction of the information as one well understood textbook.

[Farmer]

what type of schooling or education in general do you have about all this? Not flaming bro, because you sound like you know your stuff and I am just getting into the game, I am in my first quarter now. Lemme know some of the books you use and what not as well bro..

peace

[painintheazz]

Bump, please give us the info on the books.

Pain

[BrokenBricks]

I am graduating from Florida State with a degree in Biochemistry, ill be going to med school afterwards. The books are general text books. I am not at home now so i can't tell you the name of the best one. It is just called biochemistry (but a million books are, you need to know the author). The most benificial class for me was the second semester of general biochemistry. But you must take biochem one to take biochem 2, and you must take two semesters or organic chemistry to take biochem one. So if your not a chemistry major or pre-med i dont know if you could take it.

Pain, Ill give a link to buy my text book tonight when i am home, but it is about 100 bucks. But if if you guys really want to get into the procceses I promise they are easy if i give you links to some pictures that could show things like the protien metabolism quesiton i talked about before. Biochem isnt tough to understand if you have the book or pictures in front of you.

Whats your major? did you mean first 1/4 freshman? we use the semester system here.

[BrokenBricks]

OK heres a decent picture of the TCA cycle.
http://www.gwu.edu/~mpb/citric.htm
here is the main page..not good for explaining anything but will help to show why some things happen

http://www.gwu.edu/~mpb/index.html

Notice the second compound in the TCA is citrate, that is citric acid. That is why drinking 0 carb drinks with citric acid in them can still throw you out of ketosis.

[RealMenBench]

I'm in my last session of classes, and the textbook we currently have is

Advanced Fitness Assessement and Exercise Prescription by Vivian H. Heyward

I can't remember offhand the name of my Exercise Physiology book, but when I get the chance I'll post that .....

It takes time, which is cool, if you are at about 60-70% or yor MHR.

which is exactly why a target fat burning workout is at least 20 mins of moderate (60-70%) intensity .... the oxidative system kicks in after 2/3 minutes of continual exercies ... the ATP-PC system is only 5-8 seconds, and the glycolitic system is roughly a minute to a minute and a half ....

and actually the Acetyl-CoA goes to the Kreb's cycle where it is broken into CO2 and H+ ..... The ETC (electron transport chain) then takes that H+ and combines it with O2 to make water and prevent acidification ... That's when Oxidative Phosphorylation kicks in and uses the electrons from the ETC to reform ATP (energy), and it is here that Lipolysis (break down of fat) occurs .. from the fat you get your glycerol which is then sent back to the Kreb's cycle to start all over again ....

that is why you want to keep your HR in that "target range" .. if you do, you are most effeciently using the Kreb's cycle, ETC, and OP to burn fat ...

[painintheazz]

Thanks for the info bro, this is turning into a great post.

Pain

[BrokenBricks]

Realmenbench, Sorry, not a flame, but this is all wrong. Everything is backwards.

"and actually the Acetyl-CoA goes to the Kreb's cycle where it is broken into CO2 and H+ ..... The ETC (electron transport chain) then takes that H+ and combines it with O2 to make water and prevent acidification ... That's when Oxidative Phosphorylation kicks in and uses the electrons from the ETC to reform ATP (energy),"

look at this...
http://www.gwu.edu/~mpb/oxidativephos.htm

TCA makes H-, not H+
ETC doesnt use H+, it pumps them.
oxidative phos, doesn't use electrons. it is a deyhdration reaction driven by H+ gradient.

Sorry to be a jerk. But your final is coming up and you better learn it

[BrokenBricks]

"and it is here that Lipolysis (break down of fat) occurs .. from the fat you get your glycerol which is then sent back to the Kreb's cycle to start all over again ...."

Lypolisis has nothing to do with any of that. Lypolisis is breaking fat into Acetyl CoA. And is not in your mitochodria.

[RealMenBench]

what I already stated, and what I am about to post is directly from my Exercise Phys class notes ....

In the Kreb's cycle, Acetyl-CoA is broken down into CO2 and H+ (not H-)
NAD(H) and FAD(H2) take the excess H+ to the ETC
where the ETC splits the H+ atoms into protons and electrons,
the electrons then provide the energy to help reform ATP from
ADP in Oxidative Phos

[RealMenBench]

actually we both screwed up the Lypolisis ...

that is where fats is broken into 1 glycerol and 3 fatty acid molecules .... the glycerol is then sent into glycolysis and is converted to pyruvate .... the pyruvate is what is sent through the Kreb's cycle, ETC, and OP .... the fatty acids travel to the muscle fibers and are broken down by enzymes in the mitochondria (this would be Beta Oxidation) the beta oxidation creates the Acetic Acid which is converted to the Acytel CoA that you are talking about .....

I've already taken the class and passed it with a 96 avg thank you

[BrokenBricks]

This is my last response...

Acetic acid is never formed in B-oxidation.
the step that finaly produces Acetyl coa can be seen on the linked page form before. It involves thiolase cleaving a B--ketoacyl Coa by inserting a second CoAsH.

If you want to argue that B-oxidation is not Lypolis, and only trigycerol breakdown is, than fine, that is semantics. But to be fair it was this, that i meant to quote.

"That's when Oxidative Phosphorylation kicks in and uses the electrons from the ETC to reform ATP (energy), and it is here that Lipolysis (break down of fat) occurs"

The electrons making ATP is wrong, but what i was questioning is what you mean by "it is here". It seemed like you were saying that i s occurs in the same place as OxPhos, which is incorrect.

But this is the reason i refuse to continue this conversation. You are an excersize phys major. That means you are qualified to speak at this board, but if you think you know a BIT of chemistry.........your kidding yourself.

I want to cry when i think that your college is giving A's to people who think H+ EVEN HAS electrons.

"excess H+ to the ETC
where the ETC splits the H+ atoms into protons and electrons"

Either your lying that you are quoting from a book, and are just trying to lend some weight to your foggy memory, or your book isnt worth the paper its printed on.

If you really want to understand, stop talking and start reading, start thinking about what your saying. The hydrogen thing is a perfect example. Hydrogen is one proton, no neutrons and one elcetron. Hydrogen+ is simply a proton. Split that into an electron and another proton and ill recomend you for the nobel prize. UNtill then your full of poo.

Anyway, discussion over. Sorry to flame, but.......

[BrokenBricks]

I did promise to link to the book i have from when i took biochem. So...
http://www.amazon.com/exec/obidos/tg...?vi=slide-show

[RealMenBench]

The electrons making ATP is wrong

I never said that, I said Oxidative Phos uses the energy created by the electrons to carry out it's actions

http://www.med.unibs.it/~marchesi/oxphos.html#oxphos there's your proof for that ....

Acetic acid is never formed in B-oxidation.

B. lipid metabolism: most concentrated form of energy
1. chylomicrons: fatty acids transported from GI tract in lymph
2. glycerol breaks down to Glycolysis, to glucose
3. fatty acid (beta) oxidation to acetic acid to coenzyme A in Krebs cycle
4. lipogenesis: makes triglyceride (glycogen + 3 fatty acids)

.... that is directly from my class notes

Either your lying that you are quoting from a book

never said I was quoting a book, I said I was reading my class notes
(see excerpt above)

I am thinking about what I am saying, which is exactly why I went back to my notes before I posted ..... as for the H+ yeah ..... oops on me, didn't even pay attention ..... I just started typing when I read over this in my notes

3. Electron Transport system (aerobic) on mitochondrial membranes
a. transfer electrons from NADH & FADH2 -> NAD+ and FAD + 32 ATP
b. oxidation: removal of H+, loss of an electron
c. reduction: gain an H+, gain an electron (chemiosmosis)


As much as you'd love to flame I hate to burst your bubble .... I was taking things directly from my notes, and you should take your own advice about "reading" because you you actually tried to argue something that I never said .... If I'm wrong, then blame the prof (who is CSCS, NSCA, and ACM certified) that taught me, and then blame the organizations for certifing him when he doesn't know what he is talking about ... I'm no more full of poo than someone that argues something that wasn't said .....

oh wait, but you said discussion over .... oops

[Farmer]

Originally posted by BrokenBricks
I am graduating from Florida State with a degree in Biochemistry, ill be going to med school afterwards. The books are general text books. I am not at home now so i can't tell you the name of the best one. It is just called biochemistry (but a million books are, you need to know the author). The most benificial class for me was the second semester of general biochemistry. But you must take biochem one to take biochem 2, and you must take two semesters or organic chemistry to take biochem one. So if your not a chemistry major or pre-med i dont know if you could take it.

Pain, Ill give a link to buy my text book tonight when i am home, but it is about 100 bucks. But if if you guys really want to get into the procceses I promise they are easy if i give you links to some pictures that could show things like the protien metabolism quesiton i talked about before. Biochem isnt tough to understand if you have the book or pictures in front of you.

Whats your major? did you mean first 1/4 freshman? we use the semester system here.

Right on man, what do you have in mind for a career?
Anyhow the I am a freshman at a community college and going for my AAS, the class I am taking is a personal training class based around the NSCA's Essesntials of Strength Training and conditioning book, it has great information but really cannot go too in-depth on specific subjects but I have learned a lot since the start. So that could explain why I don't have the in-depth knowledge yet, that you gain from such a specific course(s). I am looking into UNLV and their Sports Training program, my goal is to eventually be a trainer for a professional football team. I'll be getting my CPT certificates in June.

Peace bro

[BrokenBricks]

I just cant keep my mouth shut...


you said exactly this.....

"That's when Oxidative Phosphorylation kicks in and uses the electrons from the ETC to reform ATP"

How am i supposed to intrepret that, in light of all of the other mistakes you (spliting H+) or your proffesor (Acetic acid) have made? i interpret it to mean you thought there was a direct link between between the ATP sythetase unit and the 4 units of the ET chain. There is not.

I know this stuff forwards and back because i have to, its my career. You dont have to argue this stuff. its not your feild, its just close to it.

Honestly, i dont dislike you or your eagerness to discuss things like this just for acedemic excersise. It can be fun. You made a little mistake and it seems like your proffesor has also. Acetic acid simply doesn't form.

Im not insulting you, im not trying to make you lok like you dont know anything. Ill be the first to admit that the breadth of my knowledge is limited to what i know about chemistry and metabloism ect. If you asked me why we should do 3 sets of 8 reps as opposed to 24 sets of one rep or whatever, i havnt got anthing inteligent to say about that. Ill bet you,an Excersize phys guy, might. But dont argue chemistry with a chemist. And kick your teacher in the nuts for the both of us. Ask him if his body is at a Ph of 4, and if not how does Acetic acid even exist in his body without becoming acetate.

Farmer I want to be an orthopeadic surgeon but i hear that 90% of people change their specialty in medical school, so im not sure i will stay with it. But it would be alot of fun to work for a pro team like you were saying. Good luck with your class.

[BrokenBricks]

"b. oxidation: removal of H+, loss of an electron
c. reduction: gain an H+, gain an electron (chemiosmosis"

AKKKK, shoot the teacher....

Im guessing if your blaming the teacher for your notes he must give you the notes that he printed himself, a generic course note sort of thing? That is pretty cool, it can be hard after a test to show a teacher that he taught you somthing wrong unless you have some proof like that.

[RealMenBench]

his notes were in little booklets that he gave us at the start of each section of the book .....

the only things we wrote out were what we wanted to from discussion... I'll see him in the gym in the morning and take him over here to this thread and see what he says about it ....

just as you said, I'm not trying to say "no, you don't know what you're talking about" .... I'm just going on what I have ...

[Farmer]

Thanks bricks, if you are part of that 90% that change, don't drop out to become a elementary school p.e. teacher good luck man!

peace

[RealMenBench]

what's wrong with elementary P.E. teachers ? hell, we need people that know what they're doing down there to build the foundation for a healthy lifestyle ....

[Farmer]

grin, that wasn't even my intention when I posted that. It was just the farthest thing I could think of from an orth surgeon but still pertaining to health, if I disrespected any pe teachers out there I am sorry maybe I should re-state it as "elementary school janitor"

peace

[BrokenBricks]

What i meant to say was that 90% change their specialty (but still become doctors) not drop out of med school. It is very difficult to get into med school, but once your in the school wants to keep you there. The dropout/failure rate for med school is as low as 1%. Law school is the opposite, easy to get in, but hard to make it through.

[ThicKen]

On a somewhat related note, does anyone keep track of their heart rate while actually lifting weights?

I'm guessing it sort of "spikes" during each set and is not very constant, but I've just noticed that if I do cardio after weight training, as soon as i grab the heart rate handle son the threadmill, it says "target heartrate reached" lol. Like, almost exactly, it's uncanny.

Any thoughts? Maybe that means crap all...