Potato, good or bad for endurance?

28-07.-2005, 05:54 PM	#1
stormer94 Registered User Join Date: May 2004 Location: Montana Posts: 415	Potato, good or bad for endurance? Crud, I had a big question posted in here and accidentally deleted it... Here it is again, in a nutshell: I've got a buddy convinced that potatos are the only food for long endurance activities because of the starch. He states that the US army, in some crazy year like 1946, decided that the potato was the ultimate endurance food. They'd send guys into battle on diets of potatos and bread, etc.... to give them long term energy. I think he's wacked out, based on the Glycemic Index, and more importantly the glycemic load. You might as well have a power bar. What's the real deal? __________________ ------- "Was" 39 year old guy Blood pressure: 143/84, Resting Pulse: 68, weight: 230 "summer 2004" 40 year old guy. Blood pressure: 121/66, Resting pulse: 45, weight: 175 1-1-2005 Blood pressure: 115/55, Resting pulse: 44, weight: 170 6-1-2005 Blood pressure: 105/52, resting pulse: 40, weight: 175 40k-TT, 1:05 Last edited by stormer94 : 28-07.-2005 at 06:18 PM.

28-07.-2005, 09:45 PM	#2
Felt_Rider Registered User Join Date: Oct 2004 Posts: 1,232	Re: Potato, good or bad for endurance? I see no extra benefit from a baked potato. Because of the higher glycemic index number it may provide a better recovery food immediately after training, but other than that it is just another quickly absorbed carbohydrate. Almost as rapid as other simple sugars. A good example for a test. Take a baked potato (skin removed) fully cooked, place it in a bowl, smash it up a little and then add a 1/4 cup of water and smash it a little more. What happens? The potato almost disolves like cotton candy or like sugar desolves in water. That is what happens once it enters our digestive system. It breaks down very quickly and triggers a larger insulin release. Where as a yam or sweet potato will digest much slower. A baked potato can be useful for a quick recovery food to replenish glycogen levels or to replenish low glycogen levels before training if for some reason levels are low before training. Other than that I have not heard of any other special endurance values. Last edited by Felt_Rider : 28-07.-2005 at 10:31 PM.

31-07.-2005, 11:32 AM	#3
wilmar13 Registered User Join Date: Dec 2003 Location: Charlotte, NC Posts: 1,557	Re: Potato, good or bad for endurance? I don't care much for potatoes as you already pointed out are pretty empty food... but a sweet potato is cheap and easy recovery food. Wrap one in saran wrap nuke it for 4-5 minutes, then smother it in butter and honey/sugar. Mmmmm good and cheap as hell.

31-07.-2005, 01:19 PM	#4
DannoXYZ Registered User Join Date: Jul 2003 Location: Santa Barbara, CA Posts: 89	Re: Potato, good or bad for endurance? "I've got a buddy convinced that potatos are the only food for long endurance activities because of the starch. He states that the US army, in some crazy year like 1946, decided that the potato was the ultimate endurance food." Could be... but that's not the rate-limiting step anyway... endurance is multi-faceted and it's only partially determined by calorie intake... let's back up a bit... I'll break up this discussion on endurance into two related systems, energy and muscular. First, let's examine our energy stores in relation to endurance: 2000~2500 calories in muscle-glycogen 500~750 calories glycogen in liver and floating around bloodstream 400~600 calories in free proteins and amino acides in bloodstream unlimited calories in fat-stores Obviously the main limitation is the 2500 calories in our muscles as that's accessed first and its supply must be replenished from outside sources. The question here is a matter of HOW best to re-stock the muscle-glycogen stores. Personally, I hate using the glycemic index as a proxy indicator of blood-glucose levels, and it's also not a good indicator of muscle-glycogen stores either. However, measuring insulin is easier than glucose concentrations but it's still a secondary indicator, kinda like using the cholesterol marker to track relative concentrations of HDL to LDL fats. But it's the best we've got to work with, so let's make the most we can of the glycemic index and its relation to measuring endurance factors. Now the main rate-limiting step in endurance is getting the CHO molecules past intestinal lining into the bloodstream where it can be transported to the muscles to replace the spent muscular glycogen. The age-old idea of using slow-release carbs like complex starches that takes a long time to digest may be fine for dieters and people who don't want to drive up their glycemic-index and the resultant fat-storage, but for athletes, it's doesn't matter WHEN all the CHO gets through, it's a matter of HOW MUCH we can get RIGHT NOW!!!. The trick is getting the highest calories/hour of CHO into the bloodstream. It does appear that training and an optimized nutrition mixture does affect the rate of CHO absorption. TDF and RAAM teams have seem to fine-tuned this process to about 400 cal/hr on the upper limit with 300-350 cal/hr to be easily obtainable, much higher than the 200-250 cal/hr rate for mere mortals like us. Now if we assume that the glycemic-index is an indicator of absorption-rate of various carbs, then yes we want a high GI CHO in order to get it from the intestines into the bloodstream as fast as possible. It appears medium-chain carbs work best, too big of a molecule takes too long to digest before its absorbed, to simple, like glucose, ends up being too dilute a mixture to get through a lot at once. The potato's high GI seem to indicate that it's a good balance in the middle and is a fast-absorbing CHO, good for performance. You also want to avoid fructose like the plague, so that leaves out dried fruits, fruit-juices and sodas sweetened with high-fructose corn-syrup (that's an evil requiring another dissertation altogether). On reason the GI isn't affected by fructose is that fructose is useless to the body. It cannot be converted to glycogen and cannot be used in ATP-production by the muscles, it cannot be converted to fat either. All fructose must be metabolised in the liver first and coverted into glucose and returned to the bloodstream before it can be used, not like the liver doesn't have enough to do already... so avoid fructose. The insulin-response to the absorbed CHO on the other hand, doesn't appear to affect endurance in any way. Typically insulin is to signal body cells to absorb free-floating blood-glucose into muscle-tissue glycogen. When those are well-stocked, it also triggers the conversion to fat in adipose tissues as well. However, when you're running a glycogen defecit in the muscle tissues, regardless of insulin levels, the digested CHO is headed straight for your muscles anyway. Experiments, primarily on race-horses, show that pre-race meals and their resultant insulin levels doesn't affect performance whether or not you're well-fed. What matters in endurance is replacing all the glycogen that you burn up later. Another factor that affect CHO absorption aside from GI is concentration in the stomach. The RAAM teams have found it's best to keep CHO concentrations high and limit the water used. This is to get as much carbs past the stomach into the intestines and too much water dilutes the mix and limits how many CHO molecules makes in in each "squirt" out of the stomach. The RAAM riders that end up dehydrated at the end of the day seems to have better endurance than those who take in water 1:1 with their expenditures. Plus too much water tends to cause gastrointestinal cramps and other distractions from performance. Another factor is adequate electrolyte consumption along with the CHO. Seems about 1000mb of sodium salt per hour is what the RAAM teams use and it balances out what's lost from perspiration. Magnesium and potassium salts are also vital for managing smooth muscle contractions and avoiding cramps. Again, another area where the potato comes in handy. One little known factoid in maintaining electrolytes is in absorption of CHO into the intestions. Each and every single glucose molecule that's absorbed through the intestine requires an exchange with a sodium. With low sodium levels, you can't absorb the carbs you're consuming, a vicious cycle when you're bonking, eh? You're going crazy and desperately looking around on the ground for scraps of carbs to eat and the body's refusing to absorb it... heh, heh So, the nutrition side to endurance is easy. While getting 300 cal/hr may not be able to completely supply a 200-mile ride, but I've found that there's some other factors other than the energy system that help made those rides easier. One of them, the muscular system, really impacts endurance and improved my average speed on a 200-mile ride... more on that in another paper.. Last edited by DannoXYZ : 31-07.-2005 at 01:38 PM.

04-08.-2005, 06:42 AM

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