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Have you heard of carbo loading? It’s a potential energy booster for endurance athletes. But for everyday exercisers it could lead to weight gain. Here’s the lowdown on carbo loading.
If you were to sit down for dinner with a bunch of runners the night before a marathon, chances are good they’d be chowing down on carbs—lots of them. You’d be surrounded by people eating heaping piles of spaghetti, rice, potatoes and bread, all in an attempt to top off their fuel tanks before the race. Most endurance athletes know that it takes a lot of carbs to keep their engines running, so there’s always a big push to pack in as much as they can the night before an event. But many endurance exercisers that I talk to don’t think about what they’re eating for the last few days before a race. That’s is too bad, because it could make a big difference in how well they perform.
The idea of carbohydrate loading—or what’s technically known as “muscle glycogen supercompensation”—is fairly simple. During endurance events, working muscles rely on heavily on carbohydrate for fuel. Much of that carbohydrate comes from storage sites in the muscles, where it’s stored in the form of glycogen. When glycogen stores run low, it’s not uncommon for athletes to ‘bonk’ or ‘hit the wall’ as they start to run on fumes. Carbohydrate loading is designed to ‘overload’ the muscles with glycogen, allowing athletes to maintain their pace and exercise longer.
In order to maximize glycogen storage, it takes more than one carb-heavy meal the night before a race. Ideally, you’ll start planning about six days ahead of time. The standard procedure calls for a gradual tapering of the amount of time spent exercising each day (usually with a rest day the day before) and then a big bump up in carbohydrate intake during the final three days. At this point, carbs should make up 75% or more of total calories. So, meals will feature abundant amounts of pasta, rice, potatoes, oatmeal, tortillas, bagels, pancakes, fruits and fruit juices.
With proper carbo loading, the amount of glycogen packed into muscle can increase as much as three-fold. And the better trained the athlete, the better the benefit. Endurance training conditions the body to put more glycogen into storage, and to do it more quickly, too.
Note, though, that I have been using the term endurance athletes. Carbo loading is only helpful for those who are regularly engaged in intense, continuous exercise lasting longer than 60 minutes. If your workouts are generally shorter than that, carbo loading won’t help you. The value of carbohydrate loading is in its ability to keep you going longer. It doesn’t allow you to workout any harder. If you use your daily stroll around the park as an excuse to pile on the pasta, you could end up just piling on extra pounds instead.
Susan is the Sr. Director of Worldwide Nutrition Education and Training at Herbalife, where she is responsible for the development of nutrition education and training materials, and is one of the primary authors of the Herbalife-sponsored blog, www.discovergoodnutrition.com. She is a Registered Dietitian and holds two Board Certifications from the Academy of Nutrition and Dietetics as a Certified Specialist in Sports Dietetics, and a Certified Specialist in Obesity and Weight Management. Susan is also a Fellow of the Academy of Nutrition and Dietetics.
Susan graduated with distinction in biology from the University of Colorado, and received her master’s degree in Food Science and Nutrition from Colorado State University. She then completed her dietetic internship at the University of Kansas. Susan has taught extensively and developed educational programs targeted to individuals, groups and industry in her areas of expertise, including health promotion, weight management and sports nutrition.
Prior to her role at Herbalife, she was the assistant director of the UCLA Center for Human Nutrition, and has held appointments as adjunct professor in nutrition at Pepperdine University and as lecturer in nutrition in the Department of Food Science and Nutrition at Cal Poly San Luis Obispo.
Susan was a consultant to the (then) Los Angeles Raiders for six seasons, and was a contributing columnist for the Los Angeles Times Health Section for two years. She is a co-author of 23 research papers, 14 book chapters, and was a co-author of two books for the public: “What Color is Your Diet?” and “The L.A. Shape Diet” by Dr. David Heber, published by Harper Collins in 2001 and 2004, respectively.