Nutrition Tuesday: What’s In Your Sports Drink? Part II

With over 60% of the United States adult population being obese or overweight, sugar gets a bad rap. Yes, lots of processed foods with tablespoons (literally!) of sugar is bad for your weight and health. However, sugar is actually an endurance athlete’s best friend!

When I say that sugar is an endurance athlete’s best friend, I’m not promoting going out and buying fistfuls of donuts, ice cream, and candy. I’m talking about simple sugars such as glucose and fructose. Back in May I wrote a post on carbohydrates: See HERE! Yesterday’s post discussed oxidation rates of CHO (aka sugar) of glucose and fructose and their affects on athletic performance.

Most sports drinks are either made with one or more of the following sugars (1):

  • Sucrose – A disaccharide (two simple sugar molecules) that is commonly known as table sugar. It is made of one glucose and one fructose molecules.
  • Fructose – A simple sugar that is found in fruit and honey. It is digested more slowly because it must be converted into glucose first by the liver. 
  • High Fructose Corn Syrup – HFCS is made using chemical processes that first convert cornstarch to corn syrup and then convert 42-55% of the glucose in the corn syrup to fructose as a way to make it sweeter (2). HFCS has been under scrutiny as a possible culprit contributing to the obesity crisis.
  • Glucose – Is the main carbohydrate found in the blood and is used to make the glycogen stored in both the liver and muscle. Dextrose is another name for glucose.
  • Glucose polymers – Are long molecular chains of glucose. These molecules are not as sweet as other molecules such as sucrose or corn syrup.
  • Galactose – Is another simple sugar. It must be converted into glucose first by the liver before the body can use it for energy.
  • Maltodextrin – A glucose polymer that is manufactured by breaking long starch units into smaller ones. It is considered a complex carbohydrate and is most commonly found in sports drinks and other processed foods. 
Some sports drinks also contain some protein. Insulin, a blood hormone, is responsible for transporting carbohydrates from the blood into muscle cells where it can be used for energy. Some preliminary research has shown that a small amount of protein added to Carbohydrates results in a stronger insulin response, which allows glucose to be delivered to muscles faster (1). This conserves stored muscle glycogen and may delay fatigue. In longer training sessions of at least 90 minutes or more, protein can be used as a source of energy if carbohydrates are not being replenished consistently (1). The protein that would be used for energy would come from muscle proteins. If protein (and carbs) aren’t being consumed, muscles would break down to provide the proteins for energy. However, one problem about carbohydrate/protein mixtures is that some people can’t stomach them. A carbohydrate/protein mixture drink is only suggested for long duration workouts over 2 hours.
How to Choose the Right Sports Drink?
Unfortunately, there is no scientific way to determine this. The best sports drink for you is the one you can tolerate at full concentration. If you dilute a sports drink so you can tolerate it, then you are most likely not getting enough carbohydrates and electrolytes, which is the purpose of consuming a sports drink versus water. Taste is important. Choose one you like and one that you will be motivated to drink throughout your workout! Another important factor to consider is the type of drink they will be serving on race day. For sprint and Olympic distance triathlons, it probably does not matter as much since the time on course is much shorter and you don’t need to carry 5000 bottles! However, in long course triathlons, especially Ironman, you will mostly like be utilizing the water stops. It’s best to try and train with what they serve on course so you can tolerate it on race day. If your a heavy sweater or if race conditions are hotter and more humid than normal, you might also need to consider the electrolyte content of the drink and/or consider taking an electrolyte pill. 

Various Popular Sports Drinks

Sports Drink
per directions
Carbohydrate (g)
% CHO
Protein
Calories
Sodium (mg)
Potassium (mg)
Carbohydrate Source
Accelerade
21
7
5
120
210
85
Sucrose, fructose, maltodextrin, whey and soy isolates 
Cytomax
13
5.4
0
50
55
30
Maltodextrin, fructose, dextrose
EFS (2 scoops in 24 oz bottle)
11
5.0
0.7
64
200
107
Complex carbs, sucrose, fructose
Fluid Performance 
24
8
0
100
200
65
Maltodextrin, fructose
Ironman Perform
17
6
0
70
190
10
Maltodextrin, fructose, dextrose
GU Brew
26
8
0
100
250
40
Maltodextrin, fructose
Gatorade
14
5.8
0
50
110
30
Sucrose, glucose, fructose
HEED (2 scoops in 24 oz bottle)
17
7.0
0
67
41
11
Maltodextrin, xylitol, white stevia
Perpetuem
18
7.5
2
87
77
52
Maltodextrin, soy isolates
Powerade
15
6.0
0
56
52
32
Maltodextrin, HFSC
(Information from various product labels)
In Summary:

  • More is not better. The body can only absorb so much ingested CHO. Studies have indicated that a combined source of carbohydrates, such as glucose/glucose polymers and fructose, can have a higher oxidation rate of CHO and increase fluid delivery while decreasing gastrointestinal stress.
  • The ideal concentration of carbohydrates is between 6-8%. Gatorade has a concentration of about 6% and has the ability to empty from the stomach just as quickly has plain water. Anything above 8% will delay stomach emptying and can cause gastrointestinal distress.
  • A sodium level of about 110 mg per 8 ounces of liquid enhances taste, optimizes absorption, and maintains body fluids. Many sport nutritionists suggest a drink with at least 200 mg of sodium per 8 ounces to decrease the chances of developing hyponatremia (low blood sodium concentration) (1). 
  • It is important to choose a sports drink that you can tolerate at full concentration. Diluting the drink defeats the purpose of drinking a sports drink.
  • To calculate your sweat rate and possible hydration needs, review my post on HydrationSports nutritionists suggest consuming about 100-250 calories (25-60g) of carbohydrates per hour during workouts (2), which can come from a combination of sports drinks, gels, bars, etc.   
~ Happy Training!



References
  1. Seebohar B. (2004). Nutrition periodization for endurance athletes. Boulder, CO: Bull Publishing Co.
  2. Clark N. (2008) Nancy Clark’s Sports Nutrition Guidebook, 4th Ed. Champaign, IL: Human Kinetics. 

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2 thoughts on “Nutrition Tuesday: What’s In Your Sports Drink? Part II

  1. I've given Perpetuem a shot and found it to be great until the weather heats up. Apparently the soy ferments causing it to taste pretty nasty. Switched over to Infiniti (whey protein) and haven't had any problems with taste.

  2. I've heard that about Perpetuem and I'm guessing where you live it that it gets super hot and might not work well! I have not personally tried Infiniti, but I have heard very good things about it!

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