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)

Diabetes in Endurance Athletes

In diabetics, regular exercise and becoming physically fit is an effective way to help manage your blood sugars and help prevent many of the chronic health problems associated with diabetes.

All of us to some degree understand that life is a balancing act.  There are obligations such as work, friends and family that we are constantly trying to keep in balance with numerous other things that we do it our lives.  For those who are not diabetic, in addition to the above, imagine now, trying to keep your blood sugars in their normal range and realizing a mistake in either direction (too high or too low) can lead to disastrous consequences. That is what it is like to be diabetic.

Exercise can add another level of complexity to that already difficult balancing act.  However, if we start viewing exercise as a medicine to control our diabetes, some of that complexity goes away.  Exercise just like any other diabetic medicine at first glance may seem to act in an unpredictable fashion but once we understand how it affects our bodies, it turns out that it actually works in a pretty straight forward way.

As a diabetic it is important to understand the variables that affect blood glucose response to exercise. Now let’s spend sometime discussing some of the most important ones.

Blood sugars at start of exercise:  Think about postponing exercise if your fasting glucose levels are greater than 250 mg/dl or less than 100mg/dl (have a carbohydrate snack to get it above 100mg/dl)

Time of exercise: Early morning (pre-meal) exercise tends not to drop your blood sugars as much as later-day (after meal) exercise so planning for this can be important

Training status:  Nothing takes the place of experience.   Whether you are a newbie to diabetes, endurance training or both, take it slow!!  A newbie’s blood glucose levels will drop a lot more for a given amount of exercise compared to a seasoned athlete.  This should be a surprise at all, the better trained you are the less energy you use, the less of a drop in your blood sugars you will experience.

Type of exercise you do (and exercise intensity and duration):  This can get a little complicated.  Generally, exercise requires energy which means utilizing blood glucose, which obviously, without replenishment, will lead to hypoglycemia.  The one caveat seems to be highly anaerobic (sub-maximal or maximal) exercise.  Highly intense exercise (such as a time trial) causes the release of several hormones that increase the production of glucose by your liver (e.g. glucagon, norepinephrine) and decrease muscle utilization of it (epinephrine, cortisol, growth hormone).  This can lead to an immediate and large rise in your blood glucose  which can last for a while.  However, once the activity is over and the effects of these hormones wear off, you may experience a precipitous drop in your blood glucose as your body is busy building muscle and liver glycogen used up during your intense activity.

The effects of any oral glucose-lowering meds or insulin that you take: Remember; think of exercise as a medication.  With this being said, it is important to understand how exercise will interact with your other meds. In general, you will likely need to lower the doses of your meds if you take them prior to exercise, but this can be variable and depends on many other factors (type of exercise, duration, recent meal, composition of meal, basal insulin levels, time of last exercise, did your glycogen stores get adequately repleted since your last exercise session? etc..)

Using a Sports Drink:  I am amazed at how often I am asked: I am diabetic, is it safe to use a sports drink and if it is, which one?  Diabetic or not, if you exercise long enough without having some exogenous source of carbohydrates coming in, you will crash.  And just like anyone else, you need to maintain proper hydration, and at some point (with longer duration events), you will need to start thinking about replacing your electrolytes.  Is there one sports drink that is better then another?  Probably not.  Find a sports drink you like, experiment with it, and learn how it meshes with your body.

It might seem overwhelming to have to think about all these variables when you exercise, but as a diabetic you are already accustomed to dealing with how various factors affect your blood sugars. This is no different.  So by understanding how exercise will affect your blood glucose levels, and how your blood glucose levels affecting our ability to exercise, you can train smart and there is no limit to what you can accomplish.

-Dr. Sal (The Raw Cardiologist)