Gels are synonymous with long distance running and carbohydrates certainly don’t get any more convenient than this. Packed in small, single-serve packets that can fit in that tiny key pocket in running shorts, runners soon discover that gels are a great way to get a fast-acting, easy-to-digest source of carbohydrate. But how do they work their magic? When should you use them? And what are the tips to make sure you get that edge?
About our expert:
Teri Lichtenstein – Accredited Practising Dietitian
Experienced marathon runner and Accredited Practising Dietitian with 11 years experience in clinical dietetics and consulting, Teri is passionate about sports nutrition. She is a member of Sports Dietitians Australia and consults to sporting organisations.
What are carbohydrate gels?
Described as a hybrid of sports drinks and energy bars, gels are power packed with a super-concentrated dose of carbohydrates, as well as key electrolytes. Because of their quick absorption into the bloodstream, many runners prefer gels because they are not “heavy on the stomach” like drinks or bars. Gels are quick to digest and with a wide variety of flavours, they taste pretty good too. There are many benefits to squirting these sticky and often very sweet substances into your mouth – gels help to delay muscle fatigue, raise your blood glucose levels and enhance performance. In fact, runners often report feeling a psychological kick-start as quickly as five minutes after consuming a gel, which makes the long distances seem a lot easier.
How do gels work their magic?
Our bodies have limited carbohydrate stores and therefore we need to take in additional carbohydrate during exercise to keep performing at the required intensity levels. Think of it like a car going on a long journey; without an ongoing supply of petrol, the car would slow down and eventually stop completely! During activity lasting longer than 60 minutes, as our muscle and liver glycogen stores become depleted, the consumption of carbohydrate provides the ongoing supplies to maintain blood glucose levels and delays the onset of fatigue. In addition, carbohydrate ingestion also exerts its benefits at higher intensity levels by delaying and/or preventing muscle glycogen depletion (also known as glycogen sparing).
All gels contain three major components:
- Carbohydrate
- Sodium
- Potassium
The benefits of carbohydrate intake during exercise are well documented and studies have shown improved performance with carbohydrate intake of 30-60 grams per hour. Many gels contain two different types of carbohydrate, glucose and fructose in varying ratios. Uptake of glucose by working muscles is more rapid than fructose; however, there is a threshold in the intestine’s ability to absorb glucose. It makes sense therefore to have a higher glucose to fructose ratio. Research using a group of trained athletes consuming a glucose and fructose combination with a ratio of 2:1 showed an 8% average improvement in endurance performance compared with those consuming an equal amount of glucose alone. It is best to avoid products with high fructose concentrations as these can cause GI (gastrointestinal) upset and drastically affect performance.
Sodium concentration is the most important micronutrient to consider when choosing any electrolyte replacement (i.e. gel or sports drink). Sodium stimulates the absorption of both glucose and water in the intestines and helps to maintain blood volume. It also stimulates thirst receptors, so you are encouraged to drink more and hence replace fluids faster.
Potassium is a key micronutrient that helps muscles contract. During prolonged exercise, potassium is gradually lost from working muscles and it is therefore vital to continually replace this important electrolyte. A runner’s body also needs an ongoing supply of potassium for the release of energy and to maintain a regular heartbeat.
Some energy gels contain caffeine. In controlled amounts, caffeine ingestion during exercise may improve performance during endurance events. Read labels and ingredient lists carefully however, if you wish to avoid caffeine. Many gels will advertise other active ingredients with performance-enhancing claims. Be careful as many of these claims are unsubstantiated and you could be paying extra dollars for limited benefits.
Gels come in a variety of flavours and provide about 420 kilojoules per serve and 24-30g of carbohydrate. Each serve provides enough fuel for about 30 to 45 minutes of running (depending on intensity). The table below lists some of the gels available from sports shops in Australia.
| PowerBarGel(Green Apple) | Gu Energy Gel(Strawberry Banana) | Gu Roctane Energy Gel(Vanilla Orange) | Torq Gel(Black Cherry Yoghurt) | PB Sports Energy Gel(Chocolate) | Carbo Shotz Energy Gel(Chocolate) | High5 Energy Gel(RaspberryPlus) | |
| Serve Size (g) | 41 | 32 | 32 | 45 | 35 | 45 | 38 |
| Energy (kJ) | 455 | 416 | 416 | 476 | 431 | 495 | 384 |
| Carbohydrate (g) | 26.7 | 25 | 25 | 28.8 | 27 | 29.8 | 23 |
| Sugars (g) | 9.8 | 5 | 5 | 9.6 | 4.1 | 5.6 | 7 |
| Carbohydrate source/s | Glucose & Fructose | Glucose & Fructose | Glucose & Fructose | Glucose & Fructose | Glucose | Glucose | Glucose |
| Glucose:fructose ratio | 2:1 | 4:1 | 4:1 | 2:1 | – | – | – |
| Sodium* (mmol/L) | 22 | 5 | 14 | 5 | 3 | 4 | 4 |
| Potassium (mg) | 21 | 40 | 55 | 11.5 | 20 | 18 | ? |
Notes: The nutrition and flavour information is based on information available on product websites as at May 2009. Glucose:fructose ratio has been rounded to the nearest whole number and is based on the nutrition information on pack/website. * As consumed with 400mL water.
How to use gels?
For first-time gel users, determining the optimal amount of gel and the timing can be confusing. It is therefore important to trial different regimens during your training runs to determine what works best for you and your body’s needs. Depending on your body weight and exercise intensity, you need to take in 30 to 60 grams of carbohydrate per hour of exercise (the longer and harder you exercise the more you need). As a general rule of thumb, for events lasting between 1-2 hours (e.g. half marathon), it is recommended to take one gel 30-60 minutes before the start and a second gel 45-60 minutes into the run. For runs lasting more than 2 hours, take a gel 15 minutes before starting and one gel every 30-45 minutes thereafter. However, if you have a high carbohydrate meal before the event, you can skip the pre-start gel. It is important to take the gels with water (at least 400mL), as this will not only ensure hydration levels are maintained and help the gel go down more easily, but very importantly, water provides optimal absorption for carbohydrates. Some athletes are able to take gels together with sports drinks, while others prefer the gel-water combination, as they find this reduces the risk of GI upset. Establish your gel-sucking habits as you train and practise different routines and combinations during training runs to find a system that works best for you.
Top tips
- Experiment with different flavours and consistencies
- Take gels during all kinds of weather – you may be using them during races on sizzling, hot humid days as well as cold, rainy mornings
- Pack a few gels for a long training session and practice taking them at different times and in different amounts to see what works best for you
- If you are out for a long run or endurance event, find a practical way to carry a few gels with you and check that you are comfortable – deep pockets in running shorts and fuel belts make it easier to carry extra gels
- All athletes are different so don’t just automatically follow the preferred gel choices of your running companions. What one runner finds beneficial can cause disastrous side effects such as abdominal cramps or diarrhea for another
Editor’s note:
Thanks Teri for your advice. I’m keen to know what my training buddies think? If you are a marathon runner or just a weekend warrior…we’d love to hear your tips and experiences. Are you a gel person or not? I call myself the Cliff Young shuffler (Aussie’s will know what I mean). On my first 14km event I used a gel at the 60min mark and felt that it was beneficial in helping me along to the finish. I can’t wait to hear your next instalment Teri, it’s great to have a sports nutrition expert on board. Remember to speak to a Registered or Accredited Practising Dietitian to help determine your optimal carbohydrate intake and assist you in developing a nutrition training program.
