Am I Burning Fat or Muscle?

[dberdinka]

During long days of rock climbing, an activity that is neither completely aerobic nor completely strenuous, I tend to eat very little food. I've always assumed that my body will burn fat if it needs more energy, however I was told this morning that it will actually burn protein (i.e. muscle) first!

 

Thats no good!! I got plenty of fat to spare and very little muscle. Any wisdom out there?

[jon]

 

Yes, and god willing we will burn your muscle then your bones, and then you will burn in eternal hell!!!! Our initial assesment is you will die!!!!

[dberdinka]

[jon]

Is Bahgdad Bob in Bham? No that really isn't true. You first would have to deplete your liver and muscle glycogen stores, and then your albumin protein in your blood. Evolutionarily speaking there wouldn't be much of a reason for fat if that was true beyond it providing insulation. You body can start breaking down your muscles for fuel, but that takes considerable effort, talking days of hard work and depletion. Check out Monique Ryan's Nutrition for Endurance Athletes if you are interested in this more.

[Bug]

dberdinka said:

During long days of rock climbing, an activity that is neither completely aerobic nor completely strenuous, I tend to eat very little food. I've always assumed that my body will burn fat if it needs more energy, however I was told this morning that it will actually burn protein (i.e. muscle) first!

 

Thats no good!! I got plenty of fat to spare and very little muscle. Any wisdom out there?

 

Check out this site. It has good information on fat/muscle/exercise/diet kind of stuff.

http://www.hussman.org/fitness/

[Terminal_Gravity]

I have used a product called Muscle Milk by Cytosport (the makers of Cytomax Sport drink). They claim that it tricks the body into burning fat instead of muscle when your system goes catabolic, exercising beyond blood stream stores or fasting. It seems to work atleast half as well as they claim even though my gut is not a good example of success. Might be worth a try.

[nolanr]

Not real brushed up on this stuff since college days, but I have to think your body doesn't start breaking down muscle tissue for energy usage until you're heading down the road to starvation. I don't think it will happen during a grueling day or even a tough weekend.

[Bronco]

I have the same sitmo myself, where I don't get hungry all day when rock climbing. Still pretty new at it though so I have a fair amount of adreneline running through my system which is a great appetite suppressor. there's my $.02

 

You should still eat something during the day to keep your body fueled up.

[specialed]

Twight probably says something about this in Extreme Alpinism but I'm too lazy to look it up. Though I do remember one quote attributed to Kevin Doyle "There's always something left to burn, even if its brain matter."

[Courtenay]

In general the body will access glycogen stores first (carbs), then fat, then finally muscle (protein), though anyone who has tried dieting also realizes that it is very difficult to burn fat only without losing some muscle mass simultaneously. Bottom line: to burn fat while preserving muscle include lean protein regularly in your diet and drink lots of water to stay hydrated. On climbs, include salty jerky, cheese, or nuts with dried fruit and bagels -- lighter weight food, the salt to replenish what you sweat away on an active day (Gatorade or Powerade can also help replenish the electrolytes, important for avoiding hyponatremia) and the protein will help minimize loss over long periods of time. Generally I find that a 60% carbs to 20% fat and 20% protein ratio works best for me in the field, though in town it's more like 45-50% carbs, 25% fat, 25% protein. Anyone else played around with ratios to find what works best for them?

[melissasendv9]

hi

 

i have pretty low body fat

and find i climb a lot better when i eat mostly high protein like whey smoothies and tuna chunks

with some raisins for carbs

 

HTH, mel

[catbirdseat]

Your brain must have glucose for energy. It cannot metabolize fat. Therefore, if glycogen stores have been exhausted, glucose can be synthesized by the catabolism of protein. This means you will lose muscle even if there is plenty of fat on your bones. You should always consume some carbohydrate to feed your brain.

[JoshK]

catbirdseat said:

Your brain must have glucose for energy. It cannot metabolize fat. Therefore, if glycogen stores have been exhausted, glucose can be synthesized by the catabolism of protein. This means you will lose muscle even if there is plenty of fat on your bones. You should always consume some carbohydrate to feed your brain.

 

My way around this problem is to stop using my brain..

[catbirdseat]

Josh, that's not possible. Remember what happened to Dan Akroyd in Ghost Busters. He was told not to think of anything, but was attacked by the Stay Puffed Marshmallow Man.

[thelawgoddess]

if you smell like ammonia, you've burned all the fat you can for the moment and are now burning muscle. (sort of.)

[iain]

thelawgoddess said:

if you smell like ammonia, you've burned all the fat you can for the moment and are now burning muscle. (sort of.)

 

or...

1) it's time for a trip to the washing machine

2) you use a narrow-mouthed pee bottle and are a bad shot.

[Dru]

or, you can't see to direct the glasses cleaning spray unless you have the glasses that need cleaning, ON.

[Winter]

or, maybe you're a wookie:

 

[iain]

too true Winter, I did forget the wOOk X-factor...

 

"He's a loathsome, offensive brute, yet I can't look away!"

 

that one kills me every time!

[Norman_Clyde]

It is true that your brain runs on glucose under normal circumstances. However, your brain's plan B, for when glucose runs out, is not to use protein from muscles. Instead, your body breaks down stored fat and turns it into ketones . These are various organic compounds which you would not usually associate with sources of nourishment for human beings (acetone, for instance). Your brain doesn't want muscle, it wants fat. Most people on a diet end up in a "ketogenic state" where they're turning fat into ketones, their breath smells funny because they're breathing out vapors of acetone and other such products, and they feel a little stoned because high levels of the stuff tend to do that. It takes many hours of fasting to bring on a ketogenic state in an adult human being, but a child who has not eaten in only few hours will have ketones in his/her urine. People in concentration camps and other starvation conditions use up their stored glycogen pretty quickly, and eventually end up with blood glucose levels of close to zero, but they don't die because their brains are running on ketones. Protein does not get converted into ketones, but into acetyl CoA ( the main hub of the Krebs cycle, but don't ask me any more than that). This means that you are not going to burn muscle unless you've starved yourself for several days, taking in no protein at all. Once you run out of glycogen, your body turns to fat next.

 

[Dan_Larson]

Party Till Ya Puke

[Bill_Simpkins]

Dan's got a point there.

[chelle]

Norman_Clyde said:

It is true that your brain runs on glucose under normal circumstances. However, your brain's plan B, for when glucose runs out, is not to use protein from muscles. Instead, your body breaks down stored fat and turns it into ketones . These are various organic compounds which you would not usually associate with sources of nourishment for human beings (acetone, for instance). Your brain doesn't want muscle, it wants fat. Most people on a diet end up in a "ketogenic state" where they're turning fat into ketones, their breath smells funny because they're breathing out vapors of acetone and other such products, and they feel a little stoned because high levels of the stuff tend to do that. It takes many hours of fasting to bring on a ketogenic state in an adult human being, but a child who has not eaten in only few hours will have ketones in his/her urine. People in concentration camps and other starvation conditions use up their stored glycogen pretty quickly, and eventually end up with blood glucose levels of close to zero, but they don't die because their brains are running on ketones. Protein does not get converted into ketones, but into acetyl CoA ( the main hub of the Krebs cycle, but don't ask me any more than that). This means that you are not going to burn muscle unless you've starved yourself for several days, taking in no protein at all. Once you run out of glycogen, your body turns to fat next.

 

The way I understand it...Ketones form from both fat and protein metabolism. You will burn through your circulating glucose first, glycogen stores second (about 1200 calories), then metabolize both fats and proteins, both can be broken down to form glucose and other molecules for energy production (including ketones). With regard to proteins circulating amino acids first to build glucose (to feed the brain, RBCs, and other tissues that use only glucose for energy), then will break down muscle tissue to form glucose and other compounds that enter the krebs cycle.

 

Endurance athletes will break down muscle tissue during a big event (more than a few hours of activity without sufficient calorie input) especially since their fat reseerves are also likely to be fairly small. People who are in starvation mode and not moving around much (exercising) may take a couple days before breaking down muscle. The brain will only covert to using ketones or lactic acid molecules as fuel after prolonged starvation. During exercise it just robs the other body cells of glucose (made by the liver by fat and protein breakdown) and forces them to use other molecules for energy.