Single or Multiple Carbohydrates Sources: which is better for performance?

First, let us be clear on one thing. Performance is all about desire, the desire to push your body to the extreme. However, do not expect great things from your body unless you treat it well. That means getting plenty of sleep, eating a healthy diet, and using a sports drink that delivers what you need when you need it.

Every sports drink out there claims to have the “right stuff” in order to improve your performance, but most of them really do not back up their claims with any real scientific data. First, let us understand the difference between improving your performance and peak performance. I can take a bag of Skittles dissolve them in my water bottle and all of a sudden I have a drink that will improve my performance. In activities over an hour, any source of carbohydrate will help improve your performance compared to water. Therefore, those “scientific” papers that show “Product X” increased their athletes’ performance when they are using water as the control groups are just stating the obvious.

Peak performance is something completely different that unfortunately the majority of us never get to experience. It is when you are good (I mean really good) and is usually reserved to the pros, semi-pros and a few seriously talented amateur athletes. These people are at the top of their sport and when they compete, in order to win, they need every bit of energy their bodies can absorb.

Now you know basically anything is better than water and most of us never achieve peak performance. Let us look at the data on single versus multiple carbohydrate sources, but first a quick chemistry lesson. Carbohydrates are one of the three major sources of calories (the others being protein and fat) in our diets. They are commonly classified as simple sugars (monosaccharides and disaccharides) or complex carbohydrates (oligosaccharides and polysaccharides).

Monosaccharides or “one sugar” are the simplest form of carbohydrates and cannot be broken down into any other sugars. When they are metabolized, they release energy, which is used to fuel the body. Examples of monosaccharides are glucose and fructose. Disaccharides or “two sugars” are (you guessed it) when two monosaccharides are combined together. Examples are sucrose (your common table sugar), which is fructose and glucose joined together and lactose (or milk sugar), which is glucose and galactose (another monosaccharide) joined together.

Complex carbohydrates are oligosaccharides (“few sugars”) and polysaccharides (“many sugars”). There are many different types of complex carbohydrates. The two that are probably most familiar to athletes are glycogen and maltodextrin.

Glycogen is how your body stores glucose and is just thousands of glucose molecules linked together. Glycogen is mainly stored in the liver and muscles. Your body can only store a limited amount of glycogen (about 2000 kcal) so after long periods of exertion without any energy consumption, glycogen stores become depleted (called glycogen debt) and performance significantly decreases. So next time you are on a group run or ride and you see your buddy starting to bonk, hand over one of your gels, and say “it’s time to repay your glycogen debt”. Then just smile at the confused look on his or her face.

Maltodextrin is produced from starch which is polysaccharide consisting of a large number of glucose molecules joined together. It is a very common additive in sports nutrition products, because although technically a complex carbohydrate, it is easily digestible and absorbed as rapidly as glucose. However, unlike glucose, maltodextrin is not very sweet.

So when you look at a nutrition label and it says, for example, carbohydrates 30 grams (g) and sugars 10g, what it means is that out of the total 30g of carbohydrates, 10g are monosaccharides or disaccharides (simple sugars) and the rest (20g) are oligosaccharides and polysaccharides (complex carbohydrates).

Now that your chemistry lesson is over, back to the question, which is better, a sports drink that contains just simple sugars, a sports drink that contains just complex carbohydrates, or a sports drink that contains both. It turns out there is a fair amount of good scientific data on this topic.

Your gut has a limited number of receptors to transport carbohydrates into your bloodstream. By using a drink that contains only one source of carbohydrates (whether simple or complex), you run the risk of overwhelming those receptors, transport will slow down, and this leads to less available energy. In addition, all those extra carbohydrates sitting around will cause water to leave your bloodstream to enter your gut. This situation can lead to abdominal pain, dehydration and decreased performance during exercise. Studies have shown that by using two different sources of carbohydrates (for example, maltodextrin and fructose) that are transported by different receptors you get increased absorption. This will allow you to supply more energy, faster, to metabolizing tissues which translates into better performance.

So although for the most of us Skittles in water is about as much performance enhancement we need, if you push yourself to the extreme and are not sure if your sports drink may be slowing you down learn for yourself what works best for you.  My advice keep it simple and natural.  Check out my recipe for my Pretty Unique Sports Drink.

-Dr. Sal (The Raw Cardiologist)

How healthy is your sports drink?

Remember the old adage: “treat your body well and it will treat you well.”  As an athlete, you should be even more concerned about what goes in your body.  It never ceases to amaze me; many athletes will pound their bodies into the ground day after day, eat highly specialized diets, and abstain from many of the common pleasures of life, all in the hopes of achieving supreme fitness.  However, if it comes in a pill, powder, or gel form, they do not discriminate and will put just about anything in their body.

Since the introduction of Gatorade, the sports drink industry has come a long way.  There is an almost dizzying array of products to choose from, with each one stating to be better than the other.  Although, it appears clear that they can enhance your performance (at least when compared to water), the question is: Are they really healthy?

Here are a couple of reasons why they may not be:

High Fructose Corn Syrup (HFCS)

HFCS is a sweetener and preservative used in many processed foods including sports drinks.  The reason HFCS is so popular is that it is cheaper and sweeter than sugar and extends the shelf life of foods.  Many experts blame increased consumption of HFCS for the growing obesity problem and adverse health effects such as diabetes.


Sucralose is an artificial sweetener, which was originally sold under then trade name Splenda.  It is about 600 times sweeter than household sugar and when metabolized does not produce any energy (or calories).  Let me say that again: does not produce energy.   Now why would you want to have something in your sports drink that makes it sweet and does not give you energy?  If that is not enough, recent evidence may suggest that artificial sweeteners may actually promote weight gain.


Another old adage: “More is better”.  Well, when it comes to vitamins this may not be necessarily true.  I will not subject you to the details of the hundreds of published studies on vitamin supplementation, but I will say this:  There is very little evidence (if any) to suggest mega supplementation does any good and much more evidence to suggest that it in fact may do harm.  So what is mega supplementation anyway?  When you look at the label and see you are ingesting several times the recommended daily allowance (RDA) that is mega supplementation.

Artificial Colors

You can recognize that your sports drink contains artificial colors by the letters FD&C (Food, Drugs & Cosmetics) that precedes the name of the color (for example, FD&C Blue 1 or FD&C Yellow 5).  Although, they are generally deemed as safe, they are artificial, and really do not belong in your sports drink.  That is, unless you really truly believe, that it is the flaming red color of your sports drink that makes you go faster.

Artificial Flavors

These are too numerous to list but let us just say this:  if you crack open the latest sports drink and it has a taste that is out of this world, chances are that it is.   It was probably made in a chemistry lab somewhere.  When picking a sports drink look for one that specifically states it contains no artificial flavors.  Even better do what I do and make you own sports drink. Check out my recipe for my Pretty Unique Sports Drink.

Unfortunately, these are not the only things to look out for, there are many, many more.  Next time you pick up your favorite sports drink, take a close look at the label.  If you see something on the ingredients list and you do not know what it is, look it up.  What you find may surprise you.  Remember, you are an athlete; your body is a temple. Only good things must go in to get unparalleled performance out.  Think about it, when was the last time you saw a neon blue temple?

Is protein really needed in endurance events?

Although, carbohydrates and fatty acids are the primary fuel sources utilized during endurance events, more recently there has been a lot of data to support supplementation with protein during endurance events. In the past few years, clinical trials have clearly demonstrated that a protein/carbohydrate drink enhances performance when compared to a carbohydrate drink alone.

The reason for this is likely manifold and somewhat elusive.  It is unlikely that the small amount of addition calories gained by drinking a carbohydrate/protein drink plays a significant role.  It is more likely because during prolonged exercise, as glycogen levels become depleted, the body undergoes a process called gluconeogensis.  Gluconeogenesis is a process that results in the generation of glucose from non-carbohydrate substrates such as pyruvate, lactate, glycerol, and amino acids.  Gluconeogensis is an energy intensive process that can lead to accelerated muscle breakdown in order to liberate amino acids to drive the gluconeogenic process.  Ingestion of small amounts of protein may help fuel the gluconeogenic process with enough protein to allow the body to avoid having to breakdown muscle.

However, having said this, this is still probably not the primary reason that a protein/carbohydrate drink enhances performance over a carbohydrate alone drink.  Another, probably, more important reason is that a protein/carbohydrate drink appears to help stem cortisol release better than a carbohydrate only drink.  Cortisol is a hormone (often referred to as “the stress hormone”) which is released in large quantities during intense exercise (a very stressful state to the body).

Normal cortisol release has widespread actions that help restore homeostasis (getting back to baseline functioning) after stress.  In the normal situation, this is desirable, but for the endurance athlete it may have grave consequences.  Although, cortisol increases circulating glucose concentrations (in the blood) which is desirable, it does this mainly by supplying amino acids for gluconeogensis by inhibiting collagen formation, decreasing amino acid uptake by muscle, and inhibiting protein synthesis. Also of importance to the endurance athlete is that cortisol also increases gastric acid secretion, potassium loss and is a potent diuretic.  So by using a protein/carbohydrate drink to stem cortisol release, and by supplying a steady stream of protein (or ultimately amino acids) use may spare valuable muscle protein.

A last and more straightforward reason (one purposed by myself) has to do with recovery.  It is widely accepted and practically endurance athlete dogma that protein/carbohydrates supplementation aides in recovery.  The question I have often asked myself is, when does recovery start?  The notion that recovery starts with the cessation of exercise is ludicrous and arbitrary.  For the endurance athlete recovery happens before, during and after exercise.  Recovery is an ongoing process that really has no starting or stopping point.  Let’s face it, exercise is a highly catabolic process. It only makes sense that you want to start rebuilding muscle (or at least slow down muscle breakdown) the minute you start exercising.

As for the issue of how much protein, the answer is no one really knows but it is probably not very much (a few grams/hour).  Protein is much harder to digest than carbohydrates (try eating a steak and than going for a run).  So, if you have too much protein during an endurance event you risk some serious GI distress, too little and you may not get any benefit.

(Reprinted from Triathlete Magazine – September 2008

-Dr. Sal (The Raw Cardiologist)