Looking around your local outdoor store, it can be pretty confusing to decipher all the marketing behind the sports nutrition products. Should you use gel, chews, or energy bars? Once you’ve picked a type, you need to decide which brand. Should you pick the gel based on maltodextrin or the gel based on brown rice syrup?

Background

Before you decide on a specific product, there’s a bit of background information you should know. When exerting yourself mountaineering, your calorie consumption can range from 300 to 800 calories per hour. An average hard day of mountaineering can use around 4,500 calories. Hiking and the like obviously uses less than this.

While you may be burning all these calories, your body cannot replenish them at this rate. The optimum rate of calorie replenishment is around 35 to 45 percent to avoid stomach cramps and decreased performance. Thus, you should eat a maximum of 280 calories per hour. The rest of your calories will come from the regular meals you eat during the day.

In addition to burning calories, you are also losing water when exerting yourself. On average, you sweat out around a liter of water for every hour of exercise. Heat or altitude can multiply this figure by a factor of 3. Obviously, this water needs to be replaced.

Your stomach can hold a little over half a liter of liquid at one time. According to Craig Connally, 20oz of water per hour is a good amount of water to drink per hour. As the old rule goes, drink before you actually get thirsty.

As most people know, when you sweat you lose electrolytes. Today, the vast majority of all the sports nutrition products all include a balanced amount of electrolytes. So, unless you’re just drinking water all day long, this generally isn’t a problem.

Maltodextrin

Maltodextrin is a corn based starch. It is a carbohydrate that has the same amount of energy per gram as sugar. What makes maltodextrin so wonderful is that it is absorbed by the body faster than glucose (sugar). When buying maltodextrin, you may notice a dextrose equivalent (DE) number on the side of the package. The lower this number, the faster it is absorbed by the body. Powdered maltodextrin will usually have a DE of 10.

Brown Rice Syrup

Brown rice syrup is sometimes used as an alternative to maltodextrin in energy chews and some gels. It consists of 50% complex carbohydrates, 45% maltose and about 3% glucose. The glucose is absorbed by the body first. The maltose takes around an hour and a half to be digested and the complex carbohydrates can take two to three hours. The overall result is that it takes a much longer time to get the energy out of brown rice syrup than maltodextrin.

Energy Gel

Energy gels are usually based on maltodextrin. GU for example gets 70-80% of its calories from maltodextrin and 20-30% from fructose. Fructose (fruit sugar) is added for sweetness so you will want to eat the gel again. Some potassium and salt is added to replace electrolytes lost in sweat. Gel makers also add a variety of trace vitamins and additives with claims of the supposed performance gains, but the main thing you’re looking for is the maltodextrin to keep you moving. A typical 1 ounce serving of energy gel has approximately 100 calories.

Eating on the go

So now the question is how much energy gel do I need and how often do I need it? As we said before, you should plan on replacing a maximum of 280 calories per hour via energy gels. So, during a hard workout you will want to take one serving of energy gel every 20 minutes. Set your watch to remind you and you will keep your stamina at an optimum level. On long hikes you don’t use nearly as much energy as a hard day mountaineering. On these days, I like to take one energy gel approximately every hour.

More Information

For a more thorough overview of performance nutrition, I highly recommend reading chapter 19 of “The Mountaineering Handbook” by Craig Connally. His excellent coverage of the recent science behind this subject will give you a thorough overview of the topic.