Based on the website WWW.CPTIPS.COM

This blog is based on the scientific content in the website Cycling Performance Tips. Idea about a new topic --forward it to the webmaster for CPTIPS.

Thursday, February 25, 2010

Nutrition. No fuel = No performance. Carbohydrates are the key!

Your muscles need fuel (Calories) to function. If you do not provide enough energy (Calories) and in the right form, your performance will suffer no matter how rigorous your training program or balance of training and rest. If you have been on a good diet, your body should have enough stored carbohydrate energy to perform at a high level for 1 1/2 to 2 hours before you bonk. For longer rides, or if you are riding daily and not replacing Calories, you need to provide additional energy in what you eat and drink (energy drinks, not water alone) to maintain performing at your best.

These Calories need to be in the form of carbohydrates, not protein or fat. In fact, you have enough fat stored in your body to exercise for days (really) but as it is not as efficient a fuel as carbohydrates (sugar) you will only be able to maintain about 50% of your personal maximum. This is why you Bonk - you are running on fat Calories alone.

Riding day after day (multiday rides) are a special case. You have to actively work to replenish, each day, what you expended that day, or, over time, you will find you are slowly running out of oomph as carbohydrate stores are depleted and fat takes over as the source of the muscle's energy.

Here is the question that prompted this post:

I am preparing for Texas Hell Week, a cycling event in Fredericksburg that incorporates 8 straight days of 100+ miles rides. I am an avid cyclist who commutes 24 miles daily and I generally put in 3 to 5 hour rides on Saturday and Sunday. I love being on the bike and am fairly strong but am concerned about nutrition after my rides. I have been using a supplement called MuscleMilk for some time as a post ride supplement to build muscle. I'm about 165 pounds (fluctuates 163-168) and 5'8" and would like to lose some weight. I don't count Calories mostly because I don't have the patience. I'd like to drop down to around 155 lbs ultimately, but my main concern right now is Hell Week.

At any rate, looking at your site and thinking about the label on a bucket of powdered MuscleMilk... that stuff has a lot of calories (~250), gobs of protein (~42g) as well as a fair amount of fat and not much CHO. My thought was to drop that in favor of Endurox R4 for post ride recovery. It has more CHO, less protein and less fat. Then I saw your recipes for drinks and figured that might be a better deal... I hate Coke. Seriously, I just think it’s a nasty substance.

Instead of drinking carbs, can I eat carbs and drink fluids and replenish in the same manner as the shelf products? I'm a little confused about what constitutes carbs in the form of glucose as opposed to fructose. If memory serves correctly fructose is fruit and glucose is ... Simple sugars? Dense multi-grain Bread? What about meat products? - GS

My comments-

1) You want to replenish the energy you expend on the ride each day with carbohydrate Calories. Maybe a smidgen of protein if you believe the articles about better carbohydrate absorption with a little protein in the mix, but no fat. So get rid of the muscle milk if it is CHO light and all the Calories are fat and protein. It provides the wrong type of Calories to support riding at your best.

2) I'd go with at least 50% of your glucose replacement plan (fructose works too) immediately post ride (first hour or two when carbohydrates appear to be stored most efficiently in the depleted body storage areas) in liquid form (that is where my fondness for Coke comes from). Then switching to complex carbs (bread, pasta, rice) for the other 50% of your needs in the evening (with fluids). But if you are light on replacing the Calories you used that day, you will probably bonk earlier the next day. And it will get worse day by day.

3) If you hate Coke, do you like any other drinks that are based on sugar syrups? Any will work. Or you can buy more expensive sports drinks if you prefer. There is a current fad to use low fat chocolate milk which tastes good and has some sugar as a post ride Calorie source. That could add a little variety.

4) Meat (protein) does not need to be pushed. You should get enough protein from a normal balanced diet and eating more than the basic amount will just get cycled into fat.

5) If you want to lose weight (eat fewer Calories than you burn on a ride) wait till after your week long ride or I can almost assure you that you will have a bad time. It is hard to ride at your best when you are CHO deficient (negative balance). Then you are riding on fat energy alone - at about 50% of your potential. And it will feel like a struggle.

Dick Rafoth


  1. Coke? Like Coke with all that sugar and fizzy stuff....I think it may make me hurl.

    Cheetos, now that is some good replacement and popcorn!

  2. If you are putting Coke in a water bottle, it will not remain fizzy for long. If you are using Coke for glucose replacement while riding, the extra fiz (and its stomach bloat effect) are to be avoided. After the ride? It is a personal choice as to fiz versus non fiz drinks.

    The use of gels, coke, and other replacement liquids and snakcs remains a personal choice without any hard facts to back up the marketing hype often encountered.

    For many years it was believed that a 2.5% concentration (of glucose or glucose polymer molecules) was the maximum tolerated without leading to delayed gastric emptying and subsequent nausea. However a recent study, in cyclists, demonstrated normal gastric emptying with 6 to 8% solutions, and nausea occurred only when concentrations were pushed above 11%. In extreme events, such as the Tour de France for example, competitors have used up to 20% carbohydrate solutions at a rate of 2 to 4 quarts an hour for long periods of time without negative gastric effects. The same is true of competitive cross country skiiers.

    The old standbys - apple juice and cola drinks - have a sugar concentration of around 10%. Although glucose polymer sports drinks can provide more Calories per quart of fluid being ingested (concentration being equal), studies have failed to demonstrate a performance advantage of complex carbohydrate drinks over the simple sugar drinks alone (assuming the same total Calories were ingested). The advantage of the polymers is the absence of a sweet taste and nauseating properties of high concentration glucose drinks, which can be a barrier to maintaining an adequate fluid intake.

    Is there a "better" sugar to use? A recent study looked specifically at absorption rates of sugars in the small intestine. It failed to substantiate any difference in absorption rates of simple glucose versus a complex carbohydrate - assuming a normal intestinal tract. A second study looked one step further along the absorption process by studying blood sugar levels (all complex carbs are broken down in the small intestine BEFORE being absorbed) to see if perhaps a difference could be demonstrated. Again, blood glucose levels were the same (both in terms of blood sugar levels and timing) with simple glucose and complex carbohysrates.

    So what is the answer?? Perception of improvement, whether placebo or unproven fact, should not be ignored. However, the scientific literature offers no credible rationale to differntiate the benefits of the glucose from Coke versus a complex carbohydrate in the commercial product sold by ***.

    Do you take in equal amounts of carbohydrates per 15 minute interval when you use cola drinks with simple glucose versus complex carbs? Gels are easier to use, and less sweet per Calorie consumed.

    Bottom line: The use of gels, coke, and other energy snacks remains a personal choice.

    Dick Rafoth

  3. Lactase is the enzyme that digests lactose. Virtually all humans make lactase at birth so that they can digest the lactose in breastmilk. Starting at about three, the age of normal weaning, humans, like almost every other mammal, naturally stop producing lactase. It's just not needed. increase sex drive