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Educate me about carbohydrates

LordOpie

MOTHER HEN
Oct 17, 2002
21,027
3
Denver
so, I know that the typical muscle stores about two hours worth of glycogen, correct?

And that after it's depleted, your body starts to use the glucose in your blood stream, yeah?

And if you don't re-supply, you'll bonk or worse, right?

Ok, so how much carbs should one eat in a day? Suppose someone is riding an average of 45 minutes/day with one day at 3-6 hours. Do you need extra carbs the night before the big ride? Or do you simply need to eat while riding?

I'm trying to reduce my carb intake as much as reasonably possible, but I don't want to damage myself on or from my big rides.
 

Westy

the teste
Nov 22, 2002
42,057
8,062
Sleazattle
Here is how I understand it from reading endurance nutrition books oriented towards athletes and not doctor types.

At low intensity, say <65% muslces burn fat. Your brain must burn carbs (sugar). Above that threshold the muscles start to burn glycogen, as the glycogen is being used it is replenished by blood sugar. Because your brain can only burn sugar your body will always try to keep the blood sugar at a certain level, it can convert protein and fat into blood sugar but it is difficult and can not be done nearly as quickly as you can burn it off. I try to eat 200-400 cals/hour depending on the pace.

During idle periods of the day you could go with keeping your carb levels lower but once you start riding you need to get carbs into your system so it can start hitting your bloodstream when you need it. Waiting until you are riding generally is too late. I like to eat something 2 hours before a ride and then again right before the ride. The meal 2 hours earlier fuels the start of the ride and the snack before the ride fuels the end. A long ride will require fueling on the go.

Of course the main problem people have with carbs is that if you get a rush of it into your system the body reacts by secreting insulin which causes the sugar to be stored away as fat. This causes the sugar rush and crash as the insulin can stay around in the blood stream longer than it is needed.

One thing to consider is that the slower carbs are absorbed into your system the less likely the insulin spike and crash will occur. Complex carbs take longer to absorb than simple sugars. Eating carbs with food that have fiber also slows down the absorbtion. Drinking 100 calories of apple juice will absorb a lot faster than 100 calories of an apple.
 

LordOpie

MOTHER HEN
Oct 17, 2002
21,027
3
Denver
Good info, thank you!

What about the whole carbo loading the night before thing? Any validity to it stuffing more glycogen into the muscles?

I've heard that consuming protein during exercise helps the body in some way, like absorbing the carbs you eat along side it or something?


(I've never paid close attention to this stuff, I just know that if I consume 200-300 calories per hour via beef jerkey, diluted energy drink mix, a cliff bar, some fruit and a peanut butter sandwich, I can ride 100 miles... I'd like to do a little better than just getting by)
 

Westy

the teste
Nov 22, 2002
42,057
8,062
Sleazattle
Good info, thank you!

What about the whole carbo loading the night before thing? Any validity to it stuffing more glycogen into the muscles?

I've heard that consuming protein during exercise helps the body in some way, like absorbing the carbs you eat along side it or something?


(I've never paid close attention to this stuff, I just know that if I consume 200-300 calories per hour via beef jerkey, diluted energy drink mix, a cliff bar, some fruit and a peanut butter sandwich, I can ride 100 miles... I'd like to do a little better than just getting by)
I think the carbo loading thing is more about making sure you are topped off than being able to store more. On a typical day if you eat dinner a few hours before bed you can go 12+ hours without food. By the time you wake up it is likely that you will be low on glycogen and other things. Breakfast is just that, a break from your night fast. Eating a large late meal (preferably slow digesting) will absorb through the night keeping things topped off for the morning. Some folks under really hard training will actually wake up in the middle of the night to eat so they can help fuel their night time recovery.

I don't know all the deep technical stuff but muslces do need a bit of protein under hard work. Since your body has no other way of storing it, it gets consumed from muscle mass. Not exactly what someone trying to stay in shape wants to do, so having some absorbed into the blood stream through digestion stops the parasitic protein loss.
 

ultraNoob

Yoshinoya Destroyer
Jan 20, 2007
4,515
1
Hills of Paradise
I've felt a marked improvement in my performance when I load carbs and protein the night before a big ride or harsh training session.

For breakfast before a ride, I eat oatmeal. 1 hr before the ride, I snack on some saltines, and pop a glucose tab within the first 5 minutes of riding. During the actual ride, I consume a diluted mix of cytomax/cytocarb II:spam:

Post ride, I slowly consume a protein shake within the first 45 min after the ride (within the golden hour of recovery). Basically, I'm feeding myself a constant stream of electrolytes and complex carbs throughout the workout. Since your metabolism stays high for over an hour after your workout, you give the body protein to convert into whatever it needs. The neat thing is, that I can regulate my consumption. If I just climbed for 30min, I take a big gulp. If I'm chillin on a flat, little sips. Never felt any symptoms of "food coma" like I do when I actually eat something.

Before I started doing this, I would bonk within 2-3hrs. Now I'm good so long as my camelback has my mix in it. I carried 6L worth of it and rode for almost 7 hrs with no adverse affects during or after the ride. Muscles were fresh within 2 hrs after the ride.
 

LordOpie

MOTHER HEN
Oct 17, 2002
21,027
3
Denver
Thanks guys. I've been chewing on the info.

So, how much carbs do I need?

Assume that I do a moderate intensity ride for an hour, four days a week with 3-4 hour rides at a slightly higher intensity on Saturday and Sunday?

(the idea is to eat as little as necessary and still be able to ride without feeling like crap the next day)

How many grams of carbs should I eat each day?
 

Westy

the teste
Nov 22, 2002
42,057
8,062
Sleazattle
It is impossible to say, it all depends on your size, metabolism and what you consider a hard effort. Probably the best thing to do would be wear a HRM with a caloric output display. Look at how many calories you burn an hour and replenish at least as much as you burn after 65% effort. For example if you burn 1000kcal in an hour with an average heart rate of 85% you would want to eat at least 1000*((85-65)/85) or aproximately 235 calories. Also remember that if you are riding through a normal meal time you probably should eat the calculated value on top of what the normal meal. This is kind of what I do and it seems to work for me although I don't do any calculations anymore and I am not trying to cut down on carbs. I wouldn't attmept to cut carbs before or during a ride at all. You are better off being fully fueled and getting a good ride in. If you go into a bonk state you can feel really crappy for days and your body will become very stingy as far as burning energy, it can actually cause you to gain weight. A good hard ride will raise your metabolism for several hours after a ride.