Figuring out the best nutrition strategies to use during exercise is another important step in your fueling routine. Consuming carbohydrate during exercise can improve performance by giving your muscles additional energy to burn—especially on a long run. Training, not race day, is the time to experiment with different types and timing of foods and beverages. The key is to eat and drink more often with less volume. As you continue to make adjustments, evaluate how you feel and how you perform. Keep a food, fluid, and training log. Fine tune, as needed, until you have a fueling-on-the-run plan that works for you.
Running on empty (glycogen depletion) leads to low blood sugar, heavy legs, and fatigue. Avoid these pitfalls by initiating your fueling and hydration plan early. In other words, start fueling soon after you begin running—not when you begin to feel tired. Be proactive with your plan!
For a run lasting less than an hour, you probably don’t need to eat during exercise. Having a pre-run snack that tops off energy stores should provide you with enough fuel for a good workout. Just remember to drink fluids to stay hydrated. Consume fluids at a rate that closely matches your sweat rate. General guidelines are 13–26 fluid ounces every hour of exercise, with small amounts (3–7 fluid ounces) taken frequently (every 10 to 15 minutes). Of course, fluid needs can vary considerably based on factors such as fitness level, body size, pace and weather conditions.
For typical endurance exercise lasting a couple of hours or less, the general recommendation is 30–60 grams of carbohydrate per hour of exercise. If your run exceeds two hours and your pace is fast, you might benefit from 45-90 grams of carbohydrate per hour. Here’s where it gets really interesting—the science tells us that just any old carbs won’t do as illustrated by the colorful graph below.
We’ve learned that if you load up on just one carbohydrate source, the transporters for that source fill up to capacity and you can’t absorb anymore—the max contribution of a single carbohydrate is limited to about 60 grams per hour. But by consuming both glucose and fructose, you take advantage of the fact that your digestive tract has two separate transport systems: one to absorb glucose and the other to absorb fructose. This dynamic duo allows both sources of carbohydrate to deliver fuel your working muscles at a faster rate.
Raisins make it easy to take advantage of this cutting-edge research because they naturally provide about equal amounts of glucose and fructose which leads to the greatest utilization (oxidation) by the muscle (see graph). The best part is that this fructose + glucose combination can lead to improved performance! The exact amount of carbohydrate that you decide to have per hour is an individual decision. Ideally, you should strike a balance between increasing carbohydrate availability during exercise to maximize performance while minimizing gastrointestinal distress.
A ¼ cup of raisins provides 31 grams of carbohydrate and 130 calories. Tuck a box into your pocket or under a wristband. Give it a try and let us know the specifics on how you raisin YOUR run!