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Low-carb diet & racing(19 posts)

Low-carb diet & racingnyvram
Apr 11, 2002 5:49 AM
I know I'm going to take alot of flak for this; but I follow a low-carb diet & do fine with riding. However I'm going to start some cat-5 racing (newbie to that aspect) and I was wondering:

(a) Are there any other low-carbers out there (who will admit it on an opinionated cycling forum) who actually race?

(b) What types of tips can you give me? I will probably opt for a banana or something to prevent bonking but are there any good low-carb bars or gels out there anyone has used to maintain their energy level?

PS I'm a fairly decent rider (but never raced) who can generally go for several hours between 18-20 mph so please don't lecture me that I need big plates of pasta & starches to even consider being a 'real' racer.

Thanks for any feedback.
low carbs DURING race???mtber
Apr 11, 2002 6:26 AM
Not to harass you, but it is my understanding that nothing but simple carbs can be processed by your body during intense exercise. Gels are very efficient and easy to use and I don't see how a few 100cal gels in a 2hr road race will blow your diet.
re: Low-carb diet & racingWayne
Apr 11, 2002 6:36 AM
To answer b, most cat.5 races aren't long enough for you to worry about bonking. But if you're worried about it, you want to take in carbohydrates so that your muscles burn this glucose and spares your muscle/liver glycogen for as long possible. Glycogen depletion is one of the main limiters in any endurance sport. I don't know how consuming protein/fats rather than carbs during an event would spare your limited glycogen stores when your body already essentially has a limitless supply of protein/fat on hand. I know bananas are a big favorite amongst people but they really are a bad source of carbs during intense exercise. They're loaded with fiber and the sugar is fructose both of which slow the rate at which the carbs get into your blood. If you're worried about maximizing the carbs absorbed you're better off going with the gels or carbohydrate drinks.
As I understand it...nyvram
Apr 11, 2002 7:03 AM
Well..if you believe what Atkins says; by 'starving' your body of carbohydrates, your metabolism shifts to burning stored fat instead of muscle protein or simple carbs. This is a state known as 'ketosis' (which you can easily verify by buying some ketone strips at a pharmacy & watching them turn purple after you've elminated carbs from your diet for a few days).

Now, seeing as how my muscle mass has increased DRASTICALLY since I started this way of eating due to my diet and exercising..and my body fat has gone down to next-to-nothing, I am inclined to believe this is so. Note that I eat TONS of protein on this 'diet'. I do not see any evidence that I'm losing muscle mass by not having a readily available (more than 30-50 carbs per day) store of carbs to burn. Its hard to tell though, since I started my exercise routine at the nearly the same time I started eating this way.

I am not worried about blowing my diet by eating carbs during the race; I guess my real question is how my body will react to an intense assualt of carboyhdrates for use during a 2 hour race since I have kept off them for so long prior to the race.

I dunno; maybe I should just 'carb-up' a day or 2 before the race to restore balance but I hear people swear that this isn't necessary so I am confused.

PS I am 6'1" and went from 250 to 175 (I'm around 180 now) in one year and have maintained this weight for the last 3 years or so. That's why I'm sticking with it; my body has really toned up far faster than I ever dreamed possible and I don't give a flying fart about watching my calories. I just eat until I'm full. My cholestorol (LDL, etc...I get checked yearly) & blood pressure are perfect for my age (35).

NOTE: I am ***NOT*** trying to start a debate or push some damn diet program with those last statements; I just want to present the whole picture here of what my experience has been and get some honest feedback. Please don't think I'm trying to be a troll or stir up controversy because I'm not. (I swear I won't bring up Motebecanes! ;-) )
As I understand it...Wayne
Apr 11, 2002 8:28 AM
I appreciate what your saying, but there are a couple of caveats. One, I don't even think Dr. Atkins or any of the low-carb diets recommend their diet for people who are doing heavy endurance exercise for the exact reason that replacing your limited carbohydrate stores would be difficult on this diet. Second, recognize that there is a difference between burning more fat sitting around the house (when essentially the only glucose you need is for brain tissue) and shifting the percentage of fat you're burning doing hard exercise when your muscles are making large glucose demands as well. I'm aware of evidence that high fat diets do indeed shift the percentage of fat vs. carbohydrate you're burning at submaximal, relatively low effort levels. But at high intensity levels like you will experience during racing you're always going to reach a point where your only using glucose or a large percentage of the ATP derived is from glycogen/glucose. Why? Because that's the fastest way to generate ATP, oxidation of fats is a relatively slow process. The harder you go the faster you need to produce ATP, so you shift from fats to glucose (and from oxidizing that glucose to not oxidizing a good percentage of it). During a race is probably not the time to worry about eating a diet that has helped you lose weight, you should be worried about making sure you make your limited glycogen stores last as long as possible. I'm not sure eating anything other than carbs DURING THE RACE will contribute to this.
Not totally on topic but some more info:mtber
Apr 11, 2002 8:46 AM
Found this on the MTB site:

Excerpt from CARBOHYDRATES 101 REVISITED By: Steve Born...

WHY COMPLEX CARBOHYDRATES, NOT SIMPLE SUGARS
AND THE TRUTH ABOUT THE GLYCEMIC INDEX
Sugar is defined as a monosaccharide or a disaccharide. The shorter the chain length a carbohydrate is, the higher it raises the solution osmolality (the solution concentration of particles carrying an electric charge) in the stomach. Simple sugar must be mixed in weak 6-8% solutions or they will sit undigested in the stomach and not pass the gastric lining, possibly creating sour stomach, cramps, or flatulence. Maltodextrin is a multiple of sugars hooked together, allowing from 18% to 24% solution immediately in transit to the liver where it is turned back to the energy cycle as muscle glycogen. As Dr. Bill mentioned, the Amylose-Amylopectin content of maltodextrin or potato starch are very similar in their chemistry to human stored glycogen. Therefore the "Gold-Standard" carbohydrate source for energy drinks, bars, or gels originates from longer-chain carbohydrates [Maltodextrins] because more caloric volume crosses gastric lining with less distress to the competing athlete. Sports drinks or gels containing simple sugars need to be extremely diluted to match body fluid osmolality. This weak of a concentration will more than likely not allow enough calories (most are up to 100 calories at a 6-8% solution) to be available to working muscles on an hourly basis.

What the above means is that complex carbohydrates are superior to simple sugars in that they allow more volume of calories to get into the bloodstream from the GI tract than anything containing simple sugars; you have more calories available for energy. The biggest problem is that once only a minimum (it doesn't take much) of the short chain sugars are present in the blood channels, a "Sugar/Insulin Spike" occurs followed by traumatic blood-sugar below-fasting depression or "Bonk". Because complex carbohydrates may enter at a relatively high 15-20% solution, the typical crashing "Bonk" is not typically as low as the simple sugar "Crash". There are several studies that show that glucose (a simple sugar) causes a greater drop in blood sugar levels (even BELOW fasting baseline levels!) than complex carbohydrates. Simply put, simple sugars are a very inefficient fuel source. Trying to use simple sugars to fuel your exercise is kind of like trying to heat your home burning newspapers in the stove. They're hot but very short-lived. If you want to keep warm you'd have to constantly add more and more newspapers to the fire…highly inefficient!

The other question people always seem to ask is in regards to the glycemic index (GI) of various carbohydrates. Prior to exercise this is critical unless the pre-workout meal is completed three hours prior to exercise, thus allowing insulin levels to return to baseline. After exercise begins glycemic index impact on insulin release is moderated DURING exercise and is inhibited because sympathetic nervous system hormones are generated in a low depleting blood sugar environment. In other words, the body has a highly effective way of regulating insulin during exercise. Processed simple sugars are usually in the 95-110 GI range, while processed complex carbohydrates are generally in the 110-130 GI-range or lower, depending on the type of maltodextrin. During exercise Glycemic Index is not a factor unless one consumes more than the liver can return to the energy cycle (again about 280 carbohydrate calories per hour maximum). I believe that everyone who concerns themselves more with the GI makeup of a carbohydrate source than the saccharide profile is making a big mistake.
That's interesting...Wayne
Apr 11, 2002 1:42 PM
makes sense since most carb/hydration drinks like Gatorade are in the 6-8% range, and they always tell you to drink a bunch of water with most gels (non-maltodextrin?). Isn't maltodextrin (is it really potato starch?) one of those artificial middle length carbo chains? I think only short (sugars) and long (starches) occur naturally. I guess from what they're saying you should consume gels with maltodextrins, or drinks with simple sugars at a 6-8% solution (like Gatorade).
What i don't get is the second paragraph and third paragraph, they contradict one another. Seems like the 2nd paragraph is talking about the resting condition, not exercising. My understanding is that a "sugar/insulin spike" doesn't occur during exercise for the very reasons they state in the 3rd paragraph, so i'm not sure about it's relevance to eating during exercise and why avoiding simple sugars would matter all that much during exercise unless for reasons stated in the first paragraph?
I don't think they're using the term "bonk" appropriately. I would say bonking is a drop in blood sugar associated with extreme depletion of the bodies glycogen stores, leading to dizziness, incoherence, a greater sense of effort but dramatic drop in performance.
Back to the original poster's question, carbs during exercise whether maltodextrin, or diluted sugars are the way to go if you're worried about maximizing your performance and not bonking. The arguements for not consuming simple carbs or even complex carbs in the Atkins or other low-carb diets just don't apply while exercising.
not a good comboColnagoFE
Apr 11, 2002 7:21 AM
You need carbs for fuel--especially in endurance sports. You may not notice it for shorter crits, but I bet you'll run out of energy for longer races.
I dolonefrontranger
Apr 11, 2002 7:57 AM
I switched to a variation on the "paleo" diet (NOT Atkins, BTW) October of last year. I've lost a lot of body fat. It's a variation of the "paleo" diet because I do eat beans and legumes, which the true paleo Nazis insist should be avoided. Mostly I avoid things like "white" starches, sugar, caffeine and dairy. All of these foods negatively impact me by causing fatigue, lethargy, headaches, blood sugar swings, etc.

I do take in simple carbs during, and immediately after I sustain a hard effort. I try to avoid wheat and gluten products because I exhibit sensitivity to them (blood sugar swings, hunger cravings). I'm also lactose intolerant. So in my case, I have to treat these types of foods like drugs, because that's how my body responds to them.

With that being said, a couple gels, bottle of energy drink, or an energy bar before / during a race don't adversely affect me. I'll also take in a small amount of simple carb during my "recovery window", i.e. 20-40 minutes after a hard effort.

It's important to remember that we are all individuals, and what works for one of us will not be a magic bullet for all. I developed this way of eating after a lot of consultation with a dietary / metabolic science Ph.D. who worked at my former job.

I grew up on a farm, and did a couple 4-H projects on feeding & animal science, then worked for 2 summers as a large animal vet intern. Scientifically, the fastest way to fatten any animal for slaughter is to feed it on grain products. The best way to create lean muscle mass (lean beef a'la "free range", or muscular, "dry" halter horses) is to feed grass, hay and roughage. Humans are no different. Think about that for a minute the next time you crave a big bowl of cereal or pasta.
I donyvram
Apr 11, 2002 8:10 AM
I have a friend who raises sheep and she has really opened my eyes to the whole 'grain-fed' v. 'grass-fed' beef. Apparently beef that you eat that has been grass-fed is far healthier for you as well. She quoted some statistics regarding the type of cholestrol each type of meat contains.

As for the argument avoing gluten & processed foods (sugar), I whole-heartedly agree. I have never felt so healthy as I have since ridding myself of products made from bleached flour and starches. I used to get headaches frequently; possibly an allergic reaction to these foods I didn't even realize I had and now I rarely have them.
Sounds like a good plan to mebicyclecoach_com
Apr 11, 2002 1:08 PM
Someone who uses a low-carb diet suggested:
"I do take in simple carbs during, and immediately after I sustain a hard effort."

This sounds like a reasonable approach to me because it allows you to continue to follow a diet that works for you, but it recognizes the much increased need for carbs at higher, race-like intensities. Although, assuming you have a "full tank" of glycogen stores at the start of a race, you probably have enough carb (glycogen) stores in your body to complete a 1 hour race pace effort without consuming carbs during the race pace effort--as someone else pointed out.

Here's what I mean about carbs at high intensities (not trying to lecture--just pointing out what I've read that the reports on the research regarding intense exercise):
18-20 mph is usually a easier to moderate intensity effort for a "fit" cyclist such as yourself, and at that level of intensity, carbs constitute a low percentage of your calories burned. So, a low-carb diet can probably create and replenish adequate carb (glycogen) stores in the body to handle this pace for sustained periods--as you seem to handle it fine. But, at 25-30 mph, carbs constitute a MUCH higher percentage of calories burned AND you use a lot more calories. So, at race pace, you would run out of stored glycogen (i.e. bonk) MUCH sooner than at a 18-20 mph pace, which indicates (in my mind) a need for you to consume some carbs during (for energy during the effort) and immediately after (to more easily replenish the used-up glycogen stores) a sustained (more than 1 - 1.5 hour) race pace effort.

Hope my two-cents was useful.
Sounds like a good plan to menyvram
Apr 11, 2002 1:35 PM
Absolutely!

Thanks a million guys, for both the info and the lack of flames. I think your advice is quite right and I will take that in for the coming race.

PS; the post about the Shaklee carb/electrolyte replinishment drink ties in quite nicely; looking to order some right now as a matter of fact. Sounds like a good product and maybe I'll carry a banana or take a Cliff bar or 2 with me as well.

I definitely need to study up on this some more as I don't want to do anything to hurt my body (worse than crashing or bonking that is). :P

thanks again
From what I've read...Wayne
Apr 11, 2002 1:58 PM
I think you're right on. At rest you can rely almost totally on fat but you still need some glucose for nervous tissue. If you totally eliminate carbs most people would deplete their glycogen stores within 24-48hrs and ketogenesis would start producing carbs from protein to get that glucose for the brain.
At the lowest levels of endurance exercise that provide some stimulant for endurance adaptations (around 50% VO2max), equivalent to most people's recovery ride effort, you're burning about a 50/50 fat/carb ratio at a pretty low rate. As your intensity increases the ratio of carbs to fat gradually increases as does the rate of ATP consumption. At around LT (90% VO2max for a fit person) you're ratio is essentially 100/0 carb/fat but a large percentage of the carb (lactate) is still being converted to pyruvate and oxidized. Once you get to 100% of VO2max (or higher for shorter efforts) you're oxidizing as much of the lactate as you can, and you're ATP demand is still outstripping the aerobic supply rate so you're producing alot of ATP "anaerobically" and getting the associated lactate accumulation.
.02 works for melonefrontranger
Apr 11, 2002 5:56 PM
Exactly. I might add that I've lost over 15 lbs and ~7% bodyfat on this program, and feel better and more energetic than I have since I was a teenager (I'm mid-30's now).

I've not bonked since I started this program, and I've done some really long rides (>4 hours) that had enough intensity to more than reach the end of my glycogen stores.

Example: I did a 2 hour, 35 mile race on Sunday, took in 1/2 bottle of Gatorade and 1/2 Balance bar within 45 minutes of the start, hung onto the other half of the Balance bar and ate a couple bites off it plus downed 2 gels during the race. For gels incidentally, I stick with GU Just Plain because the caffeine in the other flavors gives me too much 'letdown' after 30 minutes or so.

My average speed was 18mph in wind, on dirt/rough gravel, high resistance type stuff, at right around 180-185 average HR, with several spikes into the 190s to a max of 202.

I got dropped by stronger riders (training intensity issue, not diet related, plus there are often a number of pro/elite/expert MTB types masquerading as Cat 4 women at this particular event), but was able to maintain this pace essentially solo for the entire race. I felt strong (relatively, for me), and I might add that two girls from the lead group bonked and I passed them.
so, about this grass-fed beefup_hiller
Apr 12, 2002 9:44 AM
can you buy it in any old grocery store? I have been convinced this is the best kind of meat for a while, but haven't seen it anywhere (I also haven't really looked).

how much more expensive is it?

thanks
matt
contrarian hereJohnG
Apr 11, 2002 6:55 PM
I have a pretty high carb diet myself. I've never actually analyzed my diet but I eat a huge amount of grains.

I'm riding 1K miles/month and a fair amount of that is at near "race" pace (thanks to my weekday riding partner ;) I'm probably sub 10% BF but have always been fairly lean. I eat everything in sight and only add a pound if I go crazy with the power bars (they are my only "weekness").

I guess this just goes to show how much variety there is out there in terms of nutrition and likes/dislikes.

JohnG
There isn't a right answer..Wayne
Apr 12, 2002 7:20 AM
to dieting, it's whatever works for people. The low-carb diet gurus are trying to sell books, etc. so they have to dichotomize everything, so carbs are BAD!!! Paleeze! Plenty of people, most endurance athletes, etc. have functioned perfectly well on the high carb/mod protein/low fat diet for years and continue to do so. Every diet that works for somebody, works because the person is consuming less calories than they're expending. There is no magic.
ONE way of doing this is to cut way back on carbs (which of course forms a substantial % of most people's diets) thus eliminating calories. Plus now you're largely eating fats and proteins which fill you up and let you go a long time with out getting hungry, since they take a long time to digest (so you're still probably consuming less calories than you were with the carbs even if you're never hungry or feel like you're stuffing yourself). Plus you can only metabolize (either into fat or glucose via ketogenesis, the latter being a very inefficient process) so much protein at a sitting and you largely eliminate the rest (whereas excess carbs are more easily converted to fat or stored as glycogen). Plus without alot of carbs (or the wrong carbs) you don't get the swings in blood sugar, with low blood sugar being one of the primary stimulants of appetite, so again you're prone to eat less total calories. These are several reasons why low-carb diets work for some people, I'm sure there are more, but laying out a long multi-factorial explanation won't sell books, it's much easier to say "you're problem is carbs, get rid of them, I'll highlight this one metabolic pathway called ketogenesis to show you that there really is physiology behind what I'm telling you, etc. etc." The problem with Atkins/low-carb diets isn't that they don't work for some (maybe even alot) of people, it's that the advocates make alot of claims that haven't been proven. And the advocates don't seem to be willing to collect and publish data to support their claims, they rely on the typical pseudoscience strategy of telling you about X,Y, and Z in non-peer reviewed situations (popular books, TV shows) who are claimed to be "typical" examples, rather than telling you about A-Z and seeing what's typical for real. This has little impact on whether it works for any given individual but that doesn't make it O.K. to say it will work for most people, because of this reason, and there will be no negative consequenses when in fact you don't know that to be the case.
I think something like the "paleo-diet" with a moderate amount of naturally occurring carbs (fruits/vegetable/ legumes/tubers/whole grains) makes alot more sense from a health perspective than the ultra-strict no carb diets, and I think I could guarentee you that you will NEVER see a Tour de France rider using a low-carb diet (or even a modified paleo-diet) because they are largely depleting their glycogen reserves everyday, and need to replenish them by the next day. But that's not really relevant to what works for Joe couch potatoe to lose weight, or athletes (even cyclists) who aren't nearly placing the daily demands on their glycogen stores as elite or high level endurance athletes.
agreed, there is no one-size-fits-alllonefrontranger
Apr 12, 2002 9:35 AM
In animal science terms, you are *not* what we'd call an "easy keeper". Mom had a part-Thoroughbred hunter who looked like a toast rack no matter what or how much we fed him, or how often we wormed him and got his teeth done. He was just a skinny horse, period. In metabolic terms, you're his soul mate :o) Can I just mention here how much I utterly despise people like you?

Hardwired evolutionary metabolic efficiency is the reason why most of the survivors of the Donner Party were women.
that's the reason I eat so much..... it's the worms! ;) nmJohnG
Apr 12, 2002 8:34 PM