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Energy Gels, etc...

Author: Stan Reents, PharmD
Original Posting: 11/27/2007 06:31 PM
Last Revision: 12/11/2018 04:32 PM

You might say that the "modern era" of sports nutrition began when Gatorade was marketed in the mid-1960's.

Then, energy bars such as PowerBar were produced. But while these may have been helpful for cyclists and hikers, a chewy bar wasn't a very good choice for a distance runner.

Then, energy gels (see "Terminology" below) arrived on the scene. Today, athletes and others who want quick energy during exercise have an even wider variety of sports nutrition products to choose from.

In this article, I'll review gels and chewable products that provide rapidly-absorbed carbohydrates.


First, let's clarify the names I will be using in this review:

Virtually all of the manufacturers of these carbohydrate gels call their products "energy gels." But don't be misled into thinking these are caffeine-laden products like energy drinks. While some brands of energy gels do contain caffeine, most don't.

Since there's a clear difference between "sports" drinks like Gatorade and caffeine-based "energy" drinks, I want to underscore the fact that energy gels are legitimate products that athletes can use.

Another name that might cause confusion is "sports" gels. These are products that are applied to the skin. The word "gel" has a distinct meaning in the world of dermatologic pharmaceuticals. Some sports creams (eg., BenGay, etc.) are marketed in a gel form. So, a "sports" gel is a confusing term because it could be something you apply to sore muscles, or a sports nutrition product.

I also considered using the term "carbohydrate" gels but my elite athlete friends thought that was a weird term, so I scrapped that idea even though it's the most accurate label.

Thus, throughout this review, I'll use the term "energy" gels for these carbohydrate products.


It's well-established that endurance exercise that lasts beyond 60 minutes substantially depletes the carbohydrate (aka: glycogen) reserves in the liver and skeletal muscles (Wallis GA, et al. 2006). So, it's only logical to expect that, if you ingest carbs during exercise, this should keep you from "hitting the wall," as they say.

But, is there any scientific evidence?

Yes! Here are several studies showing that the consumption of high glycemic-index carbs do enhance athletic performance:

Distance Running


However, in another study, consumption of a carbohydrate gel didn't improve performance:

Eighteen trained distance runners ran 2 half-marathons, 3 weeks apart. During one, they consumed 426 ml of water, and during the other, they consumed an equivalent amount of water with a carbohydrate gel. The runners ingested 1.1 grams of carbohydrate per kilogram of body weight from the gel.

Finish time was 14 seconds faster when the half-marathoners consumed a carbohydrate gel. Certainly, this could be the difference between winning a race and finishing in 2nd place, but, statistically, it wasn't significant. Why?

One explanation is the duration of running. These were elite runners: their average finish time for a half-marathon was 71 minutes. It's possible that if they ran longer, the benefits of carbohydrate consumption would be more evident.

But this might be real reason: 3 of the 18 runners complained of GI discomfort from the carbohydrate gel. This reduced their finish time by an average of 105 seconds (Burke LM, et al. 2005).



These carbohydrate-based sports products can be grouped into gels and chewable forms. Whether it's a gel, a cube, or a bean, all of these products are intended to provide rapidly-available calories in the form of carbohydrates. Some also contain vitamins, electrolytes, and/or caffeine.

Energy Gels:

• Accel Gel (by Accelerade, Accel Gel is the only product to combine carbs and protein in a gel. (NOTE: Several other brands discussed here contain specific amino acids - see below.) Each packet of Accel Gel contains 20 g carbs with 5 g of protein, to provide a total of 100 kcal. Sodium, potassium, vitamin C and vitamin E are also included. Available in chocolate, citrus orange, strawberry kiwi, and vanilla.

• Carb BOOM! Energy Gel (by Carb-BOOM, One packet contains 27 g of carbohydrate and 110 calories. Each packet also provides sodium and potassium. They come in the following flavors: apple cinnamon, banana peach, chocolate cherry, double espresso, strawberry kiwi, vanilla, and vanilla orange. The chocolate cherry and the vanilla orange flavors contain 50 mg caffeine per packet. The double espresso flavor contains 100 mg caffeine per packet.

• Clif Shots (by Clif Bar, First, it is important to point out that Clif Bar uses the name "Clif Shot" on several different products: in addition to energy gels, they also market a recovery beverage and an electrolyte beverage under the Clif Shot name. The main carbohydrate in their energy gels is organic brown rice syrup. Clif Shot Energy Gels come in a variety of flavors: apple pie, chocolate, double espresso, mango, mocha, razz, strawberry, and vanilla. The mocha flavor contains 50 mg caffeine; the double espresso contains 100 mg caffeine.

• CytoMax Energy Gel (by CytoSport, Each packet contains 27 g carbohydrates, 110 kcal, sodium, potassium, and a much different spectrum of vitamins: vitamin A, vitamin C, vitamin E, and chromium. Available in orange and vanilla flavors.

• Enervitene Sport Gel (by Enervit, Enervitene's Sport Gel contains 18 g carbohydrate, 72 kcal, sodium, potassium, and small amounts of water-soluble vitamins in each packet. The carbohydrate sources are fructose, glucose, and maltodextrin. This gel is unique in that it also contains branched-chain amino acids. Available in cola, lemon, and orange flavors.

• GU Energy Gel (by Sports Street Marketing, GU Energy Gels contain 25 g of carbohydrates and 100 calories per packet. They recommend 1 packet (with water) 15 minutes before and every 45 minutes during exercise. GU gels come in the following flavors: "Just Plain", "Lemon Sublime", "Orange Burst", "Strawberry Banana", and "Tri-Berry".

• Hammer Gel (by Hammer Nutrition, Each packet contains 88-93 kcal. The carbohydrate source is "long-chain maltodextrin." Also includes 4 amino acids: alanine, leucine, isoleucine, and valine. Available in the following flavors: apple-cinnamon, banana, chocolate, espresso, orange, plain, raspberry, tropical, and vanilla.

• Honey Stinger Gel (by Honey Stinger, This product is based on pure honey. The strawberry and "ginsting" (their name, not a typo!) flavors contain kola nut extract, which is a natural source of caffeine. Available in banana, chocolate, "ginsting," gold, mint, and strawberry flavors.

Chewable Products:

• Clif Shot Bloks (by Clif Bar, The Clif Bar company makes several categories of nutrition products: bars, gels, and these rather unique, moist, little "cubes" that they call "Clif Shot Bloks". One packet of "Bloks" contains 6 pieces, which provides 48 g of carbohydrates and 200 calories. They recommend 3-6 pieces (with water) every hour during activity. Clif Shot Bloks come in a variety of flavors: black cherry, cola, cran-razz, lemon-lime, margarita, orange, and strawberry.

• Sport Beans (by Jelly Belly, Jelly Belly is the company that brought you jelly beans. Now, they have created Sport Beans. A single 1-oz. packet contains 25 g of carbohydrate (as sucrose and corn syrup), which provides 100 calories. Sport Beans also contain some sodium and potassium, and small amounts of the water-soluble vitamins thiamine, riboflavin, niacin, and vitamin C. According to their marketing literature, Sports Beans are for people "engaged in prolonged exercise of 60 minutes or longer." They recommend 1 packet (with water) 30 minutes before exercise, and then roughly 1 packet (with water) for every 45 minutes of activity. Sport Beans come in berry blue, fruit punch, lemon lime, and orange, none of which contain caffeine. They also offer "Extreme Sport Beans." These contain 50 mg caffeine per packet and are available in either cherry or watermelon flavors.

How do Sport Beans taste? They taste like, well, jelly beans....which is what they are, with the addition of small amounts of electrolytes and vitamins.


Taste is so subjective that it's pointless to try and recommend a product on this basis. Some people like gels that taste like cake frosting ("raspberry creme" for example), but those are way too sweet for me. I prefer the chocolate- and coffee-flavored products (especially if they contain some caffeine!). And trust me....I've tried a lot of them! One thing I can say for sure, Clif Bar's Shot Bloks have the strangest consistency of anything I've eaten in a long time.

You have to find what you like. And you should definitely figure this out before an important race. The last thing you want in the middle of a marathon is to develop a queasy stomach from something that is supposed to help your performance!


Stomach Cramps, GI Intolerance

As mentioned above, you never want to ingest something during a race if you haven't previously determined how your body will handle it. In a small study from Australia, 3 out of 18 well-trained runners complained of "gastrointestinal discomfort" when consuming carbohydrate gels during a half-marathon. Because of this, and the fact that the improvement in performance was slight, the researchers concluded that the use of commercial energy gels is not warranted during a half-marathon (Burke LM, et al. 2005).

It's possible that when carbohydrate gels cause GI cramps, athletes just aren't drinking enough water with them. (Most of the manufacturers of these gels specifically mention that they should be consumed with water.) Extensive research over the past several decades has revealed that, when the carbohydrate concentration in a sports drink is greater than 6-8%, GI intolerance and nausea are more likely.

At 6%, 200ml of a sports drink provides only 12 grams of carbohydrate. But, most of these energy gels provide 20-30 grams of carbohydrate. So, it makes sense that consuming too little water while using these energy gels may partially explain why some athletes develop GI intolerance.

The foil packet irritates my mouth!

All of the manufacturers market their gels in a foil packet so you can tear off the top and suck the contents out. But, the foil is stiff and the edges feel like they are slicing into the corners of my mouth. This may be a minor gripe, but I don't think so. Try consuming several packets during your next run and see what you think. Manufacturers need to market these products in a toothpaste-like container, ie., something without any sharp edges. On this point, Clif Shot Bloks and Sport Beans have a clear advantage.

They're expensive

Yes, they are a "scientific" blend of sugars, and, yes, some products contain other ingredients such as electrolytes, vitamins, and caffeine. And, yes, with these products you know exactly how much you're getting in each packet. But, retailing for $1-2/each, that seems high, especially when you might consume 5 or 6 packets during a century bike race. When you get down to it, these products are just simple sugars.


Liz Applegate, PhD, wrote a nice review of energy gels for the October 2003 issue of Runner's World magazine. However, many new products have been marketed since then.

In 2014, Nancy Clark, MS, RD, published the 5th edition of her popular Sport Nutrition Guidebook. This book has sold over 550,000 copies.

Readers may also be interested in these reviews:


Stan Reents, PharmD, is available to speak on this and many other exercise-related topics. (Here is a downloadable recording of one of his Health Talks.) He also provides a one-on-one Health Coaching Service. Contact him through the Contact Us page.


Backhouse SH, Bishop NC, Biddle SJH, et al. Effect of carbohydrate and prolonged exercise on affect and perceived exertion. Med Sci Sports Exerc 2005;37:1768-1773. Abstract

Burke LM, Wood C, Pyne DB, et al. Effect of carbohydrate intake on half-marathon performance of well-trained runners. Int J Sport Nutr Exerc Metab 2005;15:573-589. Abstract

Campbell C, Prince D, Braun M, et al. Carbohydrate-supplement form and exercise performance. Int J Sport Nutr Exerc Metab 2008;18:179-190. Abstract

Leelayuwat N, Tsintzas K, Patel K, et al. Metabolic responses to exercise after carbohydrate loads in healthy men and women. Med Sci Sports Exerc 2005;37:1721-1727. Abstract

Wallis GA, Dawson R, Achten J, et al. Metabolic response to carbohydrate ingestion during exercise in males and females. Am J Physiol Endocrinol Metab 2006;290:E708-E715. Abstract


Stan Reents, PharmD, is a former healthcare professional. He is a member of the American College of Lifestyle Medicine (ACLM) and a member of the American College of Sports Medicine (ACSM). In the past, he has been certified as a Health Fitness Specialist by ACSM, as a Certified Health Coach by ACE, as a Personal Trainer by ACE, and as a tennis coach by USTA. He is the author of Sport and Exercise Pharmacology (published by Human Kinetics) and has written for Runner's World magazine, Senior Softball USA, Training and Conditioning and other fitness publications.

DISCLOSURE: Neither the author, nor AthleteInMe, LLC, has any relationship with any of the products or manufacturers mentioned in this review.

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