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G.I. YO!


Snickers or an apple? The pre-climb snack is a tough call, but if you're interested in how the foods you eat affect your energy level, then the glycemic index will help. In recent years, monitoring the glycemic index (GI) of foods has caught on as a way to optimize athletic training programs, especially for endurance sports.

Originally designed for diabetics, the glycemic index  determines how the ingestion of food affects the blood-sugar level in comparison to the ingestion of straight glucose, says Eric Horst, author of Training for Climbing. The index ranks foods on a scale of one to 100 (with 100 being straight glucose) to show how quickly specific foods raise blood-sugar levels.

Maintaining steady insulin and blood-sugar levels is important to keep constant flows of energy.

For athletes, this nutritional information is a powerful tool. Climbers can use this knowledge to control energy levels and to speed recovery, says Horst.


Studies suggest athletes should slowly raise blood-sugar levels with low GI foods just prior to exertion for steady energy. To maintain these levels, you should consume low to moderate GI foods during exercise, then replenish lost glycogen stores with high GI foods directly after exercise. This last phase is especially important if another workout is scheduled within the following 24 hours, in which case athletes are advised to slowly taper back to low GI foods by the start of the next workout.

GI is a very useful tool, says Horst however, it does require some planning and discipline to reap the benefits.

Broken down into low, mid and high GI foods, each category is particularly helpful in maximizing performance depending on when you eat the food.  


Low GI foods have been proven to extend endurance, according to the authors of The New Glucose Revolution. The slow rate of carbohydrate digestion in low-GI foods helps ensure that a small and steady stream of glucose trickles into the bloodstream during [an] event. Spinach and kale have a low GI, but so do Snickers bars. Try to consume foods that aren't as processed or high in fat. An hour before you tie in, hit the boulders, or begin your trek to the wall, try these foods:

  •  Apple
  •  Chocolate milk
  •  Non-fat milk
  •  Nuts and seeds
  •  Whole-grain bread
  •  Tomato soup
  •  An orange
  •  All-Bran with pears
  •  Ravioli (beef or butternut squash)
  •  Spaghetti (almost all pasta has a low GI)
  •  Chickpea salad with vinegar dressing
  •  Black-bean soup
  •  Veggie lasagna
  •  Quinoa with veggies
  •  Orange All Sport
  •  Sports drink



Foods with a low to moderate GI are ideal during exercise to maintain blood-sugar levels and keep that steady stream of energy from spiking, then falling low. With low glycemic carbohydrates, There is less likelihood of having a rebound hypoglycemic response, says Dr. Ivy in his book, The Performance Zone. While many crag-day energy products like sports drinks or gels have a high GI, Horst recommends combining foods to moderate the glycemic response. By eating a bagel (high GI) with peanut butter, you can lower the GI of the whole meal. Throughout your day of climbing, or during a workout, try these:

  •   Banana
  •  Carrots
  •  Figs
  •  Pita bread with peanut butter
  •  Rice (not instant ice, which has a high GI)
  • Orange juice
  • Granola bar
  • Sweet potato
  • Bran muffin
  • Oatmeal
  • Raisins
  • Couscous with chicken
  • Figs dried
  • Trail mix
  • Orange Fanta


The ability of muscle machinery to regenerate itself decreases very rapidly after a workout, writes Dr. Ivy, [and] nutrients consumed 45 minutes after exercise will have far less impact in helping muscles regenerate than nutrients consumed earlier. This glycogen window is especially sensitive within the first 15 minutes after a workout but lasts up to 45 minutes post-exercise.

According to Dr. Ivy, During the resting period it will be important to replenish muscle glycogen as fast as possible, [and] high glycemic index carbohydrates will help increase muscle glycogen synthesis and will limit muscle tissue breakdown.

Horst adds, The best way to get the high GI feeding, is consumption of sports drinks. Remember to mix in some protein for recovery. Other foods that might maximize recovery:

  • Bagel
  • White bread
  • Cornflakes
  • Grape Nuts
  • Baked potato
  • Millet
  • Gnocchi
  • Waffles
  • Rice cakes
  • Rice pasta
  • Parsnips
  • Potato chips
  • Jelly beans
  • Pretzels
  • Dates
  • Watermelon
  • Gatorade

DON'T CONFUSE GLYCEMIC index with glycemic load, which estimates how the quantity of a food affects your system. Put together, they create a glycemic response, indicating the speed at which your blood-sugar rises.


High-fiber foods such as lentils have a lower GI, while highly processed or easily digestible foods (such as white bread) have a higher rating. Also, if you have a high GI food, like instant rice, throwing in some fiber, protein, and/or fat, like beans, chicken and some almonds, will lower the GI of the entire meal. Along with the body's response to carbohydrates, the grain size (larger the grain, lower the GI) and preparation (longer cooking time equals higher GI) are taken into the GI account.



Not the pub. The energy bar -- that glorified performance booster±claims everything from better performance to quicker recovery.
Here's a list of when and what bars you should eat to maximize performance.


  • ProBar
  • GoLean Bar
  • SoLo Bar
  • PowerBar Nut Natural



  • Chocolate Powerbar
  • Balance bar



  • Cookies and Cream Clifbar


Whitney Boland researched the glycemic index after reading the first edition of The New Glucose Revolution.

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