Carbohydrate Loading for Cyclists: A Practical Guide

So, you’ve been training for a big event.  You’re excited.  You’re motivated.  You’ve hit your training plan religiously and managed to stay injury free the whole way.

Good job!

The hard work will pay off on race day and continue to pay dividends though-out the rest of the year with added endurance, a bit of performance, and more importantly, confidence to know exactly how your body will respond under heavy training loads.

Months of training should be followed by an adequate taper and a sound nutrition plan (inclusive of the best endurance supplements) to make certain that you are fully rested and have properly fueled so that you can lay down the best performance on the big day.  And while you likely have a training plan that schedules out your activities for that final week, you may not have a structured nutritional plan.

So, as an athlete, you have undoubtedly heard of carbohydrate (CHO) loading in some shape, form or fashion.  Yet, few folks fully understand the process or can correctly utilize this potentially valuable tool.

As it turns out, most of us confuse carbohydrate loading with a form of sanctioned gluttony where we consume large quantities of pasta the night before a big race believing that it tops off the tank instead of amassing on the thighs and mid-section.

The goal of CHO loading is to simply show up at the starting line with an elevated (supercompensated) level of muscle glycogen.  This extra glycogen can have an extremely significant effect on delaying fatigue in endurance events lasting longer than 90 minutes.  Studies indicate that fatigue can be postponed by roughly 20% while total stored carbohydrate can be increased over 45%.

If you are targeting an Ironman, full length marathon, or half Ironman, CHO loading can have a significant impact on your results. It won’t make you faster…you won’t post shorter times on a sprint triathlon or pedal harder at the start of your bike leg but it will enable you to continue at your normal pace longer. In other words, CHO loading can be critical in preventing you from ‘hitting the wall’.

This is okay after the finish line, but not at mile 17 of a marathon.

Okay, so how does this thing work?

Carbohydrate loading has been practiced in sport for the better part of 30 years.  Up until recently, however, research suggested that there was a requirement to have a “depletion” phase as the start of the CHO loading cycle.  As such, the first several days of a 7-day protocol limited carbohydrate intake severely while moderate caloric expenditures were maintained via exercise.  It is now known that this depletion phase is not required and significant CHO loading can be accomplished in 3 to 4 days.  Even 36-48 hours of rest and high carbohydrate consumption has been shown to top off muscle glycogen.

It appears that the amount, rather than the nature, of the CHO consumed during a 3-day equal calorie CHO loading may be the most overriding factor on subsequent metabolism and endurance running performance.

The recommended range of carbohydrate you should be consuming is pretty large, with a daily intake of 7-10 g of carbohydrate per kilogram.  In general, males should target a slightly lower CHO intake (6-8 g/kg/day) than females (8-10 g/kg/day).  Women who are CHO loading within 7-10 days after the start of menstruation should increase total dietary calories by 30-35% due to the influence of estradiol on glycogen storage.

Putting it all together

You’ll likely need to try carbohydrate loading as part of your normal training activity, especially in the days leading up to exceptionally long rides and long runs to get the timing right, learn the overall process of what works and what needs to be changed.

As with any dietary change, there can be some stomach upset by switching foods, so keep in mind that you’ll want to stay with the easier digested foods and foods you enjoy… and who doesn’t enjoy bread, pasta, rice, potatoes.

However, stay away from empty calories.  High fat and high protein foods should only be considered once your carbohydrate demands have been met.

Don’t get tricked into fuelling up with rich desserts and cheesy pasta dishes, which are often favorites at carbo-loading evenings. These dishes are often higher in fat than carbohydrate and can hinder your ability to reach your carbohydrate targets.

For starters, try a 2-day carbohydrate load at the higher end of the intake (say 8-10 g/kg/day) before your weekend long run or bike.  On another week, schedule a 3-day loading period at the lower end of the band (say 6-8 g/kg/day).

The stereotypical 150 pound person equates to 68 kg of body mass (pounds divided by 2.216 equals weight in kilograms).  Therefore, 6 g CHO/kg for a 68 kg person would be 408 grams of carbohydrate or 1632 calories… and that’s a lot.  For a 150 pound, 5’7” female, the daily caloric requirement assuming no exercise is around 1700 calories.  Add exercise expenditure (say 500 calories from a 5 mile run) and daily expenditure totals 2200 calories.  As such, 1632 calories should be from carbohydrate and the remaining 568 should be protein and fat.

Be wary of high fiber foods, as they may hinder your ability to reach your carbohydrate demands and may have additional gastrointestinal consequences come race day. During the final 24 hours before an event, liquid meal supplements can be helpful, allowing you to meet carbohydrate targets while leaving you with an empty stomach that feels ‘light’ and ready to race.

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