It is a time honored tradition to carb-load with a heaping plate of pasta the night before an endurance event. This has roots in research conducted in the 1960’s. Different studies have been conducted since that shed new light on the body’s utilization of energy during endurance events.
There are three main versions of the standard carb load:
1) The original carb load was developed by Gunvar Ahlborg, a Swedish scientist, in 1967. His theory was to deplete the glycogen (the body’s stored form of carbohydrate) stores prior to the carb load, starting about a week before the event with three days of low carbohydrate intake (about 10% of total calories). Then the next three days was a carbohydrate intake of about 90% of calories with a reduction in exercise intensity.
2) In the 80s, a modified regimen was developed, eliminating the depletion phase and increasing carbohydrates to 70% of intake for three days, also with decreased training. This is the most popular regimen today.
3) In the 90s a new regimen was developed by scientists at the University of Western Australia. This regimen calls for normal diet and light training until the day before the race with a very short, very intense workout and 12g of carbohydrates per kilogram of lean mass for 24 hours.
Activity level has a big impact on how often you need to “carb up”. Someone hammering away at the CrossFit WOD everyday has a higher need for carbs than someone following a standard split-routine of “3 sets, 8-12 reps, chest and triceps”. A sprinter has a higher need for carbs than a distance runner, contrary to what conventional wisdom would have you believe. As a rule, the higher the intensity of the effort, the more you’re tapping into muscle glycogen for fuel rather than fat.
This gets even more complicated when you factor in gender. “Because higher levels of estrogen inhibit carb utilization, women naturally burn more fat and metabolize carbohydrates differently,” points out Karen Dolins, a sports nutrition professor at Teachers College, in a Muscle & Fitness Hers article. “Several studies have shown that women don’t benefit at all from classic carb-loading regimens.” One, in fact, found that men who carb-loaded increased their glycogen stores by 41 percent and improved their cycling performance by 45 percent, while women showed no effects unless, in addition to a high percentage of carbs in their diet, they also ate 30 percent more calories than normal. If your head is not spinning yet, add fluctuating monthly levels of estrogen and progesterone hormones which can affect a woman’s receptivity to carb-loading.
Carb-loading, like nutrition, for performance is a science. All variables must be taken into account for it to work the way you want it to. In other words, eating seven bagels the night before running the marathon is not going to make a difference if you haven’t tweaked your diet and training volume/intensity on the days leading to the event. It might, however, have you stopping at every port-a-potty during the race. 😉
It is not completely clear to me either how eating a huge plate of pasta is expected to only be stored in the form of glycogen in your muscles. The body can only hold so much of it in the liver and muscle cells with all excess being stored as fat.
It is a much better strategy to have a rock solid nutritional foundation. If you eat vegetables, fruits, nuts, the good fats, and lean protein on a consistent basis, you should be able to go out on any given day and knockout any challenge you are presented with. On race day, have a a breakfast of slow releasing carbohydrates like oatmeal with milk and fruits. During the race eat or drink small foods that would keep your blood sugar levels stable and your electrolytes in balance all of which would also prevent you from “hitting the wall.”
And if you can’t veer away from the carb loading tradition for Pete’s sake don’t do pasta (unless you want a side of extra saddlebags that is). Here’s a better substitute: a plate of grilled veggies or sweet potato with a lean protein (chicken, lean steak, fish, etc.). Enjoy!