Fat burning and carbohydrate replacement
Question about calories...follow up on Sunday's conversation with Chris G.
Posted by Eve on June 28, 2004 at 07:37:14:
If is correct that you burn @100 calories per mile while running, why is it necessary to consume calories while on a long run? Can you really convert what you eat during a run into a useable form of energy? Why can I not, just as easily, use what is stored on my behind?
Theoretically, we can only store enough glycogen for a couple... cont.
Posted by Bruce on June 28, 2004 at 08:04:17:
In Reply to: Question about calories...follow up on Sunday's conversation with Chris G. posted by Eve on June 28, 2004 at 07:37:14:
Theoretically, we can only store enough glycogen for a couple of hours of running, biking etc. That being said, the trick is to get your body to burn fat as fuel. That comes from doing long runs. Eating would be the last thing that I'd worry about for a run under three hours, or 30 miles. You can go a long way if you keep yourself hydrated properly. I buck conventional wisdom and hydrate with a drink containing caffeine. If I didn't have a bad knee, I could run for hours on just that.
PS Feel free to knock holes in the above!
Re: Question about calories...follow up on Sunday's conversation with Chris G.
Posted by Steve on June 28, 2004 at 08:07:46:
In Reply to: Question about calories...follow up on Sunday's conversation with Chris G. posted by Eve on June 28, 2004 at 07:37:14:
There are great books out there to answer all these question. I read one by Alberto Salzar. In short, yes, you burn 100 to 120 calories per mile depending on your weight and effort.
Your body stores approximately 1400 to 2000 (depending on training and when you last ate and what you last ate) of glycogen (the readily available sugar stored in muscles and your liver). After that point you start burning fat which is a lot more difficult for your body to break down. That difficulty is why we hit the wall when running a marathon. So you need to supplement during the run and not when your body needs it but before (it takes some time - I think I've heard from 20 to 40 minutes). Products like GU are easy digested forms of sugar which converts easily to glycogen.
This is a short and sweet, non-scientific explanation which others can probably do better at explaining. Bottom line you can run so long that you start breaking down fat (my gut, your butt) but it won't be a very pleasant long run. You also start breaking down muscle at that point, too.
As I understand it....
Posted by Brian on June 28, 2004 at 09:09:17:
In Reply to: Question about calories...follow up on Sunday's conversation with Chris G. posted by Eve on June 28, 2004 at 07:37:14:
As I understand it the rate one uses up glycogen is a big function of effort. In other words, the harder the run (or quicker your pace), the quicker glycogen is depleted.
Long, slow runs train your body to use stored fat while speedwork just accustoms you to burning only the most readily accessible glycogen.
If one's sole running goal were to lose weight, this fat burning could be accomplished entirely through easy aerobic efforts at no more than 65%-70% heart rate. Anything faster than that probably doesn't really help train your body to use fat.
So, slow paces require less carbo replacement fuel than race paces would and the wall is to a large degree a function of speed.
Good also to keep in mind that gels and sports drinks also offer sodium and potassium electrolytes which are also necessary over longer workouts.
Ultra running info
Posted by Ken Bonus on June 28, 2004 at 09:31:05:
In Reply to: Question about calories...follow up on Sunday's conversation with Chris G. posted by Eve on June 28, 2004 at 07:37:14:
Pace is definitely a factor for fat burning. Here is a link to our ultra club's website where there is some usefull information from Shawn McDonald, who coaches a number of ultra runners:
http://www.movinshoes.com/surf/shawn.html
Re: Question about calories...follow up on Sunday's conversation with Chris G.
Posted by Dr Dave on June 28, 2004 at 09:33:31:
In Reply to: Question about calories...follow up on Sunday's conversation with Chris G. posted by Eve on June 28, 2004 at 07:37:14:
In addition to what's already been mentioned, calories taken in on longer exercise sessions seem to help the brain. Remember the brain can only run on carbohydrate/sugars and is very sensitive to low levels. Mind/body --- if the brain is clicking properly, trained athletes can push though rough patches including the end of a Marathon or long distance training.
more male wisdom...
Posted by matt on June 28, 2004 at 09:35:15:
In Reply to: Question about calories...follow up on Sunday's conversation with Chris G. posted by Eve on June 28, 2004 at 07:37:14:
Hey Eve,
Steve pretty much hit the nail on the head. I would simply add this:
You used the word "necessary" in regards to caloric intake; that is a loaded word. Generally speaking, it's not often "necessary" to ingest food while running; one must run pretty dang far before this is the case (as Bruce has mentioned.) The trick is to "push the envelope": that point Steve described, when your body starts burning fat as a primary energy source. This is accomplished by gradually running longer at a relatively easy pace. This teaches your body to burn an increasingly higher proportion of fat to glycogen. Your body is generally burning both, and although fat is harder for your body to break down, it provides a lot more "bang for the buck". So the more fat your body is capable of utilizing at a given pace, the less glycogen you use, which in turn allows you to run further and faster.
Blah blah blah... the point I guess I'm trying to make is this: don't automatically consume calories during long runs. Everybody's needs are different. Listen to your body and learn for yourself when eating and drinking are "necessary" for you.
Speaking for myself, I've learned I generally have to eat something 2 hours prior to a run, or I'll run out of gas. If I'm running over 1:45:00, I'll definitely need some water. If I'm running over 2 hours, a pack of Gu, or some Gatorade is helpful, but not usually necessary. If it's real hot out, the replenishment point is significantly sooner.
You asked whether your body could "really convert what you eat during a run into a useable form of energy". The answer is "hell yeah it can!" It's an odd feeling to be sure: usually I have no real sense of what food I'm burning at a particular moment. It could be my breakfast or last night's dinner, I have no idea. But after running a couple hours on a hot day, and running out of gas; you eat some Gu and suddenly you know exactly what food your body's burning! You can actually feel a change come over you, and suddenly there's just a little more "oomph" to your stride, and your mind becomes more focused.
Ok, I gotta quit typing. I'm just trying to compensate for my not being able to run lately. See ya round!
Does the burning of fat and the breakdown of muscle happen at the same time?...
Posted by Eve on June 28, 2004 at 09:43:30:
In Reply to: Re: Question about calories...follow up on Sunday's conversation with Chris G. posted by Steve on June 28, 2004 at 08:07:46:
Does the burning of fat and the breakdown of muscle happen at the same time?...and is that really what "the wall" is...the time when your body has used up its glycogen stores and begins burning fat and breaking down muscle?
The "wall" is when you run out of gas.
Posted by Bruce on June 28, 2004 at 10:49:16:
In Reply to: Does the burning of fat and the breakdown of muscle happen at the same time?... posted by Eve on June 28, 2004 at 09:43:30:
The "wall" is when you run out of gas. Lots of points made that are worthy of discussion.
good posts on a complex subject
Posted by ed on June 28, 2004 at 12:01:09:
In Reply to: Theoretically, we can only store enough glycogen for a couple... cont. posted by Bruce on June 28, 2004 at 08:04:17:
it can get pretty confusing. the "rules" of biochemistry and physiology are pretty specific in terms of how energy gets produced from different biomolecules. the pathways involved are both well defined and intricate, and understanding them in practical everyday exercise is complicated further by introducing the variables of how long, how fast, individual metabolism, etc. if it was simple biochem, we wouldn't need exercise physiologists to help us understand why Lance can average 33 mph in a 42 kilometer time trial and why most mortals could only hold that pace for about 1 minute (if that).
i think it's pretty accurate to say that most of the actions and consequences of energy metabolism happen simultaneously, with different emphasis on a particular energy source (glycogen from muscle and liver, blood sugar, fatty acids, etc.) changing as exercise progresses. in other words, you don't burn all your blood sugar before starting on glycogen, don't deplete all your glycogen before you start burning fat, and don't burn all your available fat before you start breaking down muscle, etc. Certainly though, as one energy source becomes more depleted, the other pathways are up-regulated to compensate for the demands made on the body.
the big variable, i think, comes in different people's individual metabolic requirements, which are a function of their own physiology (age, conditioning, genetic make-up, etc.). that's why some people can go out and hammer on an empty stomach (like Bruce) and others (like me) are GU junkies (which, by the way, is processed during a workout as simple sugars and not converted to glycogen first--glycogen being the storage form of glucose). the great thing about our metabolisms, as several people have noted, is that they are trainable.
gee--i hope this doesn't sound too pedantic! i'm really interested in this stuff though--it's too bad that exercise physiology is so hard to work in (small and underfunded).
cheers, ed
Brain vs. Muscles
Posted by Judy on June 28, 2004 at 12:44:25:
In Reply to: Question about calories...follow up on Sunday's conversation with Chris G. posted by Eve on June 28, 2004 at 07:37:14:
following up on Dr. Dave...recent article in Runner's World reported on testing that showed that low sugar in the brain is what shuts down the system (hitting the wall); there's still plenty left in the muscles. So the trick on the longer runs/races is mostly to keep the brain happy. Also, fat metabolism is slower, as I remember, so in races, one strives to keep on the sugars... BUT runners stomach metabolism essentially shuts down (relative to bikers stomachs) so it becomes very individual to balance water/sugars/metabolites intakes in long races and not to take in too much and puke.
For whatever its worth...
Posted by g on June 28, 2004 at 12:52:55:
In Reply to: Question about calories...follow up on Sunday's conversation with Chris G. posted by Eve on June 28, 2004 at 07:37:14:
all the comments given are reliable and sound advice. I'd only add that in the old days pre gu/gatorade. I (everyone) used to suffer badly over the last 5 0r 6 miles of marathons. Most all back (late 70s early 80s) only offered water too. Not actually knowing why I felt so dead and mostly by accident I decided to take butterscotch candies and pin them to my shorts and suck on them in the late stages, couldn't hurt right? They worked beautifully, Sugar of course is not the best thing but when your body is glycogen depleted, but even refined sugars do help. Eve, On that 22 I did yesterday I ate the whole container of those super bite samples and the quick usable energy was very noticeable.(although I didn't love the product) Also, I only use gu w/caffine in competition as some studies indicate that small amounts can help in the transition of glycogen to fat burning. Again when you eat one it is almost instant where you go from Mr whiny sissy baby to Mr rabid dog. Since gu I actually look fwd to the last 10k of a marathon and find the early going mostly filler to where the good stuff is later in the race. I eat gu every 5M in a marathon from the gun. I would recommend that anyone should start taking a packet on long training runs and find a brand/flavor that works for you. To completely contradict everything I just said you will notice me sometimes on long runs not eating or drinking a thing, this is to help my body get used to functioning while dehydrated.(might actually help but at the very least it is good mental training) This may have helped slightly in that oven at Boston as I was used to running dry? The science of all my technics might be completely screwed but by trial and error this is what I do.....
one more tip
Posted by g on June 28, 2004 at 13:02:40:
In Reply to: For whatever its worth...... posted by g on June 28, 2004 at 12:52:55:
gatorade in my experience is horrible stuff. It will upset your stomach and therefore block absorption into your system. It sounded like Brian got Gator-Gut at Boston amongst other day of, out of anyones control freak conditions. I told him of the gu and water diet I use, which he tried at Sugarloaf...I rest my case.
Dr Peter Millard (multi time trials qualifier) says if you must use the crap dilute it to half strength and that will help. The manufactures of it still market it as a sports recovery drink but it is actually mixed to strong for that and it is much closer to being just another can of soda pop.
Wow, Eve, I didn't mean to provoke such a scientific discussion!
Posted by Chris G. on June 28, 2004 at 13:40:03:
In Reply to: Question about calories...follow up on Sunday's conversation with Chris G. posted by Eve on June 28, 2004 at 07:37:14:
I was simply lamenting the number of miles needed to burn off one measly scoop of Ben & Jerry's!!
quick read on marathon metabolism
Posted by Judy on June 28, 2004 at 13:40:06:
In Reply to: Question about calories...follow up on Sunday's conversation with Chris G. posted by Eve on June 28, 2004 at 07:37:14:
http://www.bbc.co.uk/science/hottopics/marathon/suitability.html
and for us smaller folk, 1/2 a GU is plenty at a time with water I find.
this topic could continue for days I think.
ummmmm ice cream.....
Posted by Judy on June 28, 2004 at 13:43:37:
In Reply to: Wow, Eve, I didn't mean to provoke such a scientific discussion! posted by Chris G. on June 28, 2004 at 13:40:03:
but this summer, no one has chocolate chip, my favorite, i'm down to black raspberry chip yogurt...ok, but not chocolate chip. sigh
lab studies concur....
Posted by Brian on June 28, 2004 at 13:55:10:
In Reply to: one more tip posted by g on June 28, 2004 at 13:02:40:
I've used both gatorade and gu quite a bit at different times in training and found that gatorade is ordinarily quite satisfactory in replenishing fluids and cheap carbs. But I can't disagree with Gary's conclusion that for me at race effort the gatorade was what gave me stomach cramps in the heat at Boston. Don't know the relative effect at Sugarloaf of the alternate gel/water/cool temps. But it certainly was a combination that worked much better for me.
I do like gel just fine --- just wish I could figure out how to get one down without getting my fingers sticky -- which bugs me inordinately during the late miles of a marathon.
I've learned to pay attention to Gary's advice -- with the shear number of his marathons, his laboratory experience is unmatched.
about 8 hours into a 24 hour adventure race I was in a bad way and >>
Posted by ed on June 28, 2004 at 14:01:10:
In Reply to: Question about calories...follow up on Sunday's conversation with Chris G. posted by Eve on June 28, 2004 at 07:37:14:
about 8 hours into a 24 hour adventure race I was in a bad way and my support crew luckily had the foresight to start stuffing me with real food and i recovered pretty quickly. about 16 hours into it they fed me pasta and espresso/mocha which really helped to get my butt over the mountains. between gorges i pounded Double Caffeine Power Gel to help me stay awake and moving and it worked great. i finished in 23 hours and 45 minutes, the first (and only) solo entrant.
i found it pretty tough to keep my energy level up on just GU and Power Bars.
Ya. That's a different ball of wax altogether.
Posted by Bruce on June 28, 2004 at 14:06:51:
In Reply to: about 8 hours into a 24 hour adventure race I was in a bad way and >> posted by ed on June 28, 2004 at 14:01:10:
One would have to eat if he was expending that much energy.
Re: lab studies concur....
Posted by g on June 28, 2004 at 19:01:06:
In Reply to: lab studies concur.... posted by Brian on June 28, 2004 at 13:55:10:
I used to get Gator-Gut all the time and thought everybody felt that way (they probably do)..after all it is a marathon, it's supposed to be hard, Right? Wrong, when I stopped drinking the crap and quickly felt like somebody wasn't driving a knife blade up under my ribs causing me to take shallow 1/2 breaths. Its amazing how much better you can run when you are not doubled over in pain.
I was surprised to hear the organizers were handing out...
Posted by Eve on June 29, 2004 at 09:55:39:
In Reply to: Question about calories...follow up on Sunday's conversation with Chris G. posted by Eve on June 28, 2004 at 07:37:14:
boiled or baked potatoes for sustenance at the Jay Mountain Challenge (an adventure mountain marathon in Jay Vermont, late July).
