Fueling Training

[tomUK]

Suppose you have two riders – John and Tom.

Tom is 5’ 11” and weighs 150Lbs. His body fat percentage is 5%.
John is 5’ 10” and weighs 200Lbs. His body fat percentage is 15%.

From calculations we can determine that Tom has 26,250 Calories ‘available’ in body fat, while John has 105,000 calories ‘available’ in body fat (almost 4 times the amount).

Now if John and Tom both eat the same meals on Friday totaling 2,500. Saturday they both go off on a ride at 11am after eating the same breakfast (say 300 calories). Assuming they both have power meters on there bike and that they both ride at 70% of their Lactate Threshold Power then who would ‘bonk’ first, or would they both ‘hit the wall’ once they had complete the same amount of work.

My reason for asking this question is two-fold. I am trying to understand how the body uses fat for energy. Obviously there is not an ‘endless’ supply as my calculations suggest. Of the 26,250 calories available to Tom he cannot gain access to this during the ride else he would never bonk but surely he can access some of it.

If I were to go out on an endurance ride this Saturday and try to maintain an average wattage of 180W (FTP is 292) over 2 hours (maybe not an endurance ride to some) and use 1200Calories (as indicated by my Power Tap) then how many calories should I be looking to eat prior to the ride. How long before I get on my bike should I eat this amount? When riding, after the first hour I take in 240 calories/hour. Hence on a two hour ride I would effectively eat 240 calories. Normally I consume 200 calories 1 hour prior to the ride and as mentioned above complete 1200 calories of work.

The only problem I have is after the ride. While I often eat a turkey sandwich within 30 minutes of getting home, 2-3 hours later I always feel really **** and not good within myself. I am wondering if this is due to not eating enough prior to the ride.

Sorry for the long post – any help would be greatly appreciated.

Thanks.

 

[tafi]

Whoa dude! Too many numbers and too much information!
You don't need to be so scientific about your eating other than ensuring you eat enough to be satisfied.

Going on some simple reasoning I would suggest that Tom is less able to dip into his fat stores than John (Tom has the body fat level of many professionals) who has a bit to spare. As to who would bonk first, I can only hazard a guess at Tom because of this fact. I will look into it for you with a physiologist.

As to your own predicament. Experimentation is generally the only way, I have found to finding the solutions to fueling since we are all different individuals with different needs. Generally having plenty to eat before the ride is better for you since you will feel less hungry afterwards and less likely to eat everything in sight as soon as you come in the door. I do not trust equipment to tell me how much I should be eating. This is something that only your body can tell you. The power tap only tells you how many calorie have gone into the wheel. There are power losses in the drivetrain and your legs (nothing is 100% efficient), there are also losses as you breathe, balance, think, and wave to the beautiful girls at the roadside.

You say that you eat a turkey sandwich as soon as you come home from your ride. If you had been riding between morning to lunch time and have a turkey sandwich afterwards, you still need to have lunch too. The turkey sandwich is eaten so that it is quickly absorbed and to replenish some of what you have just spent. But you must still eat the meals you normaly would if you weren't cycling. Maybe you still do but this isn't clear from what you have said above.

In short, there is more to be gained by listening to your body than by listening to the power tap. Because you don't feed the powertap.

 

[Ted B]

Assuming both are in equal physical condition:

John weighs more and has a greater muscle mass, which means he burns more energy and bonks first.

Even if they had the same muscle mass, John bonks first in the hills because he has to overcome the extra weight. John also bonks first in the flats because he has a greater frontal area and creates more aerodynamic drag.

Other than this, how much fat stores each has shouldn't affect when they bonk, simply because each has plenty enough to supply the small amounts of fat oxidized at that training level. When they do bonk, obviously John has a larger static supply of energy, although that is probably not an issue except in a hypothetical case.

As far as eating calories to fuel your ride, remember that you will not absorb 100% of what you eat. In fact, if my memory serves correct, you can expect to eat somewhere in the neighborhood of 4 X the calories you expect to burn to break even in a caloric sense.

 

[tafi]

Originally posted by Ted B
Assuming both are in equal physical condition:

John weighs more and has a greater muscle mass, which means he burns more energy and bonks first.

Even if they had the same muscle mass, John bonks first in the hills because he has to overcome the extra weight. John also bonks first in the flats because he has a greater frontal area and creates more aerodynamic drag.

Other than this, how much fat stores each has shouldn't affect when they bonk, simply because each has plenty enough to supply the small amounts of fat oxidized at that training level. When they do bonk, obviously John has a larger static supply of energy, although that is probably not an issue except in a hypothetical case.

As far as eating calories to fuel your ride, remember that you will not absorb 100% of what you eat. In fact, if my memory serves correct, you can expect to eat somewhere in the neighborhood of 4 X the calories you expect to burn to break even in a caloric sense.

Ah..... but no one said anything about frontal area and you don't know muscle mass from body fat percetage. I know this from a fact as I myself have dense bones. It was also said that both riders were to ride at the same relative level of exertion no matter what the terrain so whether they happen to ride at the same speed or not (or have the same air resistance or not) is immaterial.
This is the problem with trying to compare two individuals. In order to know the answer difinitively you have to see them both tested. Too many variables.
We are all individuals and we all must find our own way to the right path. Science will give you some general guidelines but only you are aware of your own needs.

 

[Ted B]

Originally posted by tafi
Ah..... but no one said anything about frontal area and you don't know muscle mass from body fat percetage.

That's only a detail which I pointed out to expose why the scenario was purely hypothetical. It doesn't change the fact that assuming the ONLY difference between the two is body fat, what I said in the paragraph beginning with, "Other than this..." holds true.

 

[westonboege]

I am having the same problems as tomUK. I am about 6'2 and around 170 pounds... I am relatively new to cycling and only ride between 25-30 miles per day... but after a ride... whether i eat a full meal or just a snack... i will feel terrible a little bit after a ride... i usually end up laying down to watch some tv and pass out in a dead sleep for a couple hours..

I have come to the conclusion that i just need to eat more throughout the day than i have been eating. It is really hard to find out or estimate how many calories you are actually burning. And from what ive read its not healthy to create a energy deficit larger than 500 calories per day. I have used a few calorie counters and they have said that i burn around 3600 calories per day... while i was trying to keep my calories down to 2500 per day... after a few days/weeks my body started storing everything i ate as fat (or so i think) because it probably thought i was starving. I have just started eating more and more calories and am experimenting a little bit.

I think for some people its harder to interpret what their body is trying to say. When i first started cycling a couple months ago i was eating a lot of vegetables and the like. I would always feel full but i would get these headaches which i think were hunger headaches. I would feel like was gonna explode but i was not getting enough calories.

i dont know if i am just rambling or if this helps at all.. just my experiences...

 

[tomUK]

conclusion: more pies and beer for us!

Hard to tell what the real issue is. Yesteday I went out and rode for 2 hours, 1hr 20 mins was completed keeping my HR between 60-65% max. The other 40 minutes were intervals whereby I kept my wattage at 265 (91% of my FTP).

Today I am feeling pants, aside from not sleeping too well i feel like my heart is about to give out - maybe it is!

It doesn't make sense to me! I've been doing this fitness marlarky for 10 years now, maybe this cycling business is best left up to the pros!

Classified:
Bike, power-tap and trainer for sale!!