What is Carb Back-loading?

Carbohydrate (carb) loading is a well-known nutrition method that endurance athletes have been

practicing for ages. The classical regimen of carb loading involves a 3-day “depletion phase” of hard training and low carbohydrate intake, followed by a 3-day “loading phase” of tapered training and high carbohydrate intake before an event lasting more than 90 minutes.

What you may or may not have heard of before is carbohydrate back-loading which is a technique that is most popular in the world of weightlifters and bodybuilders. Carb back-loading piqued my interest after reading Pam Smith’s account on how she was able to win the 2013 Western States 100 mile endurance run. Pam wasn't about to give up her “carboholic” lifestyle and instead worked with a fitness professional to find an eating style that provided her with metabolic benefits, yet also fit her lifestyle.

Carb back-loading is a form of intermittent fasting. You eat little to no carbs during the morning and early afternoon hours until after a late afternoon workout when you have free carbohydrate reign. Carb intake then continues for the rest of the day. The concept behind this regimen plays to the daily rise and fall of insulin sensitivity in muscle and fat cells and the exercise-induced increase in insulin sensitivity in muscle cells. The theory posits that carbohydrates should be consumed at a time (after exercise) when it is used for glycogen storage gains in the muscle cells rather than for fat storage in fat cells. By depleting glycogen stores early in the day, you increase insulin sensitivity in the muscle cells so that when you do eat carbs, they are transported to muscle cells rather than fat cells.

This post is not a judgment of this dietary pattern; it is simply meant to bring awareness to readers of a style of eating that may pick up in popularity (especially if Pam wins again this weekend!) There are only a handful of studies looking at the effects of carb back-loading with most “facts” coming from anecdotal evidence.  As with any diet, don’t be afraid to be a skeptic, do some research and ask questions. Keep an open mind. Nutrition is a science, but one with no explicit scientific answer. So we keep experimenting, keep questioning and keep testifying.

What is your experience with carb back-loading? Have you dabbled in carb back-loading or know of someone who has benefited from this pattern of eating?

Peanut Butter Alternatives: Are they better than Regular?

A day is not complete without the creamy—sometimes crunchy—stick-to-the-roof-of-your-mouth goodness that can only be experienced with peanut butter.

This month's 'Ask the Dietitian' compares the most popular brands of low-fat, low-calorie peanut butter alternatives, Better’n Peanut Butter and PB2, with natural peanut butter.

Visit TrailRunnerMag.com and check it out!