A: Carbohydrates continue to get a lot of press, often with a negative or misleading slant. This has led to some runners trying to avoid, restrict or reduce carbs. Let's be clear right from the start: carbohydrates are one of three macronutrients that the body needs.

Carbohydrates come in many types, and some have more nutritional value than others. As with all foods, look for minimally processed carbohydrates from real food sources. Vegetables, fruits, legumes, pulses, grains and grasses provide easy-to-digest energy as well as important vitamins, minerals and fibre. Foods that are refined, highly processed or have added sugar—such as fruit juice, cookies, muffins, yogurt, bagels, wraps and even dried fruit—have less nutritional value than whole foods.

If you are a competitive runner (elite or recreational) and race-day performance is your goal, then carbs are still king when it comes to energy. Studies continue to show that you will run faster following a high carb diet before your race rather than choosing a low carb diet or being in a carb-depleted state.¹

Many athletes are currently following or showing an interest in a low-carb-high-fat (LCHF) or high-protein diet in an attempt to lose weight or become leaner. Please note: being lean does not necessarily equal being able to run better or faster! Yes, it is true that fat oxidation (using fat for energy) increases when carbs are restricted. But you cannot race or train at high intensity without carbohydrates. Why? Fats cannot be used anaerobically (without oxygen). When you run faster, you will burn a higher percentage of carbohydrates and a lower percentage of fat, due to the lack of oxygen. Since your body has a limit to what it can store as glycogen (approximately 90 minutes of activity if well fuelled), you will need to slow down to an intensity where your body can burn an alternate fuel once you run out—that is, if you aren't supplying the body with side sources of carbohydrate.

For runners (and other athletes) who are training or racing less than three hours, carb loading in the traditional sense isn't necessary. Why? Because the body, under normal balanced eating conditions, will likely have enough stored energy to get the job done. Just make sure you are eating a balanced, minimally-processed diet.

Carb loading becomes more relevant for races or workouts longer than three hours. Here are some carb-related considerations in advance of your next marathon, endurance event or long, intense workout:

• Practice consuming the same foods you will eat the day before the event once or twice in training to confirm that they will work and not cause any issues.
• The day before the event is not the time to worry about "whole wheat vs. white" when it comes to pasta or bread. Most experts recommend reducing fibre in the days leading up to the event to minimize the effect on the bowels, but if you typically eat a higher fibre diet, dramatic changes might also have a negative effect. In other words, maintain your status quo.
• If you are trying to stick to specific dietary trends such as the "paleo" diet, consider carbs from root vegetables such as yams, squash and potatoes instead of more traditional sources such as bread, pasta and grains.

The current research no longer supports a depletion phase prior to your carb load. Rather, you can shift your eating proportions slightly and add 5 to 10% more carbs two to three days before the event. For example, if you are someone eating a 2500 calorie diet consisting of roughly 50% carbohydrate, 25% fat and 25% protein, you would adjust that to roughly 60% carbohydrate,15% fat and 25% protein. This equals an add-on of approximately 65 grams of carbs—roughly the same as three gels, a single bagel, a cup of cooked sweet potato or two cups of apple juice. As you can see, this is not a lot of extra carbohydrates, especially when you consider the portions at your typical pasta party. Remember that you'll also need to reduce your intake of fat and/or protein to keep calories the same.

Trying a carb-depleted workout can be a good thing in your training program to test your body and your mind. Be warned that you are going to deplete your body more than normal, so you should adjust your pace and energy expectations accordingly. You are going to feel more fatigued during and after, and your recovery will be slower than from a normally fuelled workout. You are also increasing your risk of illness and injury, so don't make this a regular occurrence.

Your dietary choices should be based on your goals as an athlete and not on the opinions of the media or your friends. If you are a runner interested in general health and fitness who isn't preparing for a mega-endurance event, you really don't need to worry about consuming a high percentage of carbohydrates in your daily diet. As long as you have some carbohydrates—and maybe a little extra in the days leading up to a race—you'll be good to go

References:
1. http://www.mysportscience.com/ single-post/2016/12/26/LCHF-diets-and-performance-in-elite-athletes