How can you maintain good energy when you’re exercising for longer than 60 to 90 minutes? By eating enough calories of foods that settle well…!

The standard recommendation for fueling during endurance exercise has been to target 1 gram of carbohydrate per minute of exercise (60 grams of carb per hour, the equivalent of 240 calories for a 150 pound athlete). The research, originally done with just glucose, indicated consuming more than 60 grams of glucose per hour offered no additional benefits. The body has a limited number of glucose transporters and can carry only 60 grams out of the intestines, into the blood stream and to the muscles.

Recent research indicates consuming a variety of sugars (that is, more than just glucose) allows more fuel to become available per hour. That's because different types of sugars (carbs) use different transporters. Generally, athletes consume more than just glucose. (Sports drinks, for example, tend to be glucose+fructose.) Let's say you eat a banana that consists of many different types of sugars and uses many different transporters. Your muscles will have access to more fuel (up to 90 g carb/hour; 360 calories) than if you consume just one kind of sugar (as might happen with some engineered foods).

Variety is a wise idea—as is practicing yoru fueling during long training sessions so you can learn what works best for your body. Some people like engineered sports candy and gels, others prefer dried pineapple and gummy candy. Take your choice--just experiment during training to determine if 200 to 300 calories per hour is the right amount for your body.

“Oh, I didn’t know I could eat candy or regular food” commented the novice marathoner. She was training for her first 26.2 mile event, and was barely able to complete the first 10 miles. She was afraid to eat before she trained, fearing the food would talk back to her. No wonder she was running out of energy! She needed to fuel her body better. This would mean training her intestinal tract to tolerate food and fluids.

During the runs, she drank just water because the one time she had tried a gel, it upset her intestinal tract. I asked if she had tried gummy bears, hard candies, twizzlers, or peppermint patties. She hadn’t even thought about those options. She had limited herself to the engineered sports foods that she’d seen advertised abundantly in running magazines. I invited her to experiment with standard foods to which her body was accustomed. She started with small nibbles pre-run – a saltine cracker, a pretzel, a chunk of banana. She then added bigger portions as her body got used to the pre-run fuel.

During her long runs, when she began to run out of energy, I suggested she try some sugary candy. Starbursts became her favorite way to consume the energy she needed to enjoy miles of training. By targeting about 200 calories per hour (after the first hour of running), she was able to maintain high energy during the long runs. She experimented with lots of food options, and found that she better enjoyed standard foods than the engineered products.

Give food a try? For more information, see my Food Guide for Marathoners: Tips for Everyday Champions.

Nancy Clark MS RD