Is Carb Loading a Bad Idea?

Carb-loading is a strategy that has been commonly used by endurance athletes for quite some time. In the days leading up to a long run or race, marathoners will gorge themselves with carbohydrates. The idea is to bolster your glycogen supplies before the big race.

For instance, Runner’s World states: “The easiest way to achieve a simple, successful carb-load is to include carbohydrate-rich foods at every meal and snack [starting as early as five days prior to your race]. This means bread, pasta, rice, cereal, potatoes, and fruit should be mainstays. Simple sugars and refined grains… get the green light in the days leading up to the race.”

This can work well for really fit athletes who have an intense workout regimen or a race on the horizon, but even then it has the potential to backfire if done incorrectly, or if you ordinarily follow a low-carb diet.

There are some compelling reasons for professional athletes to rethink carb-loading, in part because high-fat, low-carb diets provide more long-lasting fuel and have an overall better impact on metabolism.

Meanwhile, carb loading is totally inappropriate for the vast majority of non-athletes who exercise casually, as this type of regimen could lead to weight gain, digestive issues, and even chronic disease.

The Downsides of Carb Loading:

There are a few issues with the idea of carb loading the night before, or in the days leading up to, a marathon or other intense sporting event. Carbs are stored in your muscles and liver in the form of glycogen, which your body uses as fuel. Once this fuel runs out, fatigue sets in and your performance suffers.

Carb loading helps to increase your glycogen stores so that you’ll have more energy and be able to run farther before running out of fuel. However, if you’re burning carbs as your primary source of fuel, you’ll still need to refuel during a marathon.

If you need to refuel your body in the midst of the event anyway, then your previous carb loading was, partly futile. Sport scientist Ross Tucker, PhD, states; “…just like you don’t plan to drive all the way across the USA without filling up [your gas tank] again, you don’t run the NYC marathon without planning to take any carbohydrates during the race. And so when we have the opportunity to constantly refuel, and provide the body with carbs [in-race drinks, gels, bars], then the loading phase becomes rather more redundant/unnecessary.”

Not only is carb loading largely unnecessary, but it can backfire too, causing you to put on extra pounds of water weight (as your body stores water with carbs). The extra weight from carb loading could easily cancel out any performance benefits, according to Tucker.
He recommends following your normal diet in the three days leading up to a race, and perhaps slightly increasing your carbs, and focusing on how to adequately refuel your body during the course of the race as your best option.

If You’re Fat Adapted, You Need Very Little Carb Replacement, Even During Exercise:
If you’ve been following a low-carb, Paleo-style diet, or a high-fat, moderate-protein, low-carb diet, your body is probably already fat adapted.

Our ancestors were adapted to using fat as their primary fuel, but nearly all of us are now adapted to using sugar or glucose as our number one fuel source instead. One way to tell if you’re fat adapted or not is to take note of how you feel when you skip a meal. If you can skip meals without getting ravenous and cranky (or craving carbs), you’re likely fat-adapted.
If you are overweight, have high blood pressure, diabetes, or are taking a statin drug you most likely are not adapted to burn fat as your primary fuel.

Being able to rely more on fat for energy during exertion spares your glycogen for when you really need it. This can improve athletic performance and helps burn more body fat.
If you can work out effectively in a fasted state, you’re definitely fat-adapted.

Replacing non-vegetable carbs with healthy fats and fasting intermittently, are among the most effective ways to encourage your body to change from burning carbs to burning fat. So for those of you already following a Paleo diet or similar, you’re likely quite efficient at burning fat for fuel and will require very little carb replacement even during intense exercise.

There is some evidence that switching to a higher-carb diet just before a race, after you’ve been on a low-carb diet, can help to “top off your tanks” to boost your performance. This strategy is highly individual. For many, this strategy may backfire, as the sudden carb consumption may lead to headaches, nausea, bloating and other symptoms as well.

What’s the Right Pre-Workout Nutrition?

Only when your glycogen stores are depleted will your body move to using fat as its fuel. And it’s this fat-adapted state that results in improved energy utilization and other benefits, like stem cell regeneration and tissue repair, along with decreased body fat, reduce inflammation, and increased insulin sensitivity.

If you carb load prior to exercise, you will actually be inhibiting fat burning and many of the metabolic benefits of exercise, even if it enhances your performance temporarily.

For this reason, fitness expert Ori Hofmekler recommends flooding your body with stress-activated food nutrients (SAF nutrients) prior to a workout. These nutrients mimic the effects of intermittent fasting and exercise. He explains; “Once ingested, SAF nutrients demonstrated the capacity to increase animal and human survivability. Some of these nutrients have shown to mimic the anti-obesity, anti-diabetic, and anti-aging effects of exercise and fasting on the body. The point is, food rich in those exercise-mimicking nutrients is ideal for pre-workout. Not only that it can prevent setbacks with the fat burning and healing impact of exercise, it may actually enhance that impact. …Note that some of the most potent SAF nutrients are no longer part of our diet. These hard-to-find nutrients occur in barks, roots, pits, and peels, which we don’t normally eat. However, some foods within our reach contain high levels of exercise-mimicking SAF nutrients such as phenols, caffeine, theobromine, catechins, and immune proteins and thus can potentially yield powerful synergy with physical training.”

So where are these nutrients found?

1. Whey protein from grass-fed cows
2. Organic black coffee
3. Unsweetened cocoa
4. Green tea

Exercising while in a fasted state is actually ideal. But if you feel weak or nauseous while exercising on an empty stomach a high-quality whey protein shake can be an ideal pre-workout snack. A study published in the journal Medicine and Science in Sports & Exercise demonstrated that consuming whey protein (20 grams protein/serving) 30 minutes before resistance training boosts your body’s metabolism for as much as 24 hours after your workout. This in turn promotes muscle protein synthesis, boosts thyroid, and also protects against declining testosterone levels after exercise. In practical terms, consuming 20 grams of whey protein before exercise and another serving afterward may yield the double benefit of increasing both fat burning and muscle build-up at the same time. You can play with the dose, as that is an average (depending on your weight and stature, you may need half that amount or up to 50%-75% more).

Exercise and fasting together also yields acute oxidative stress, which actually benefits your muscle triggers genes and growth factors, including brain-derived neurotropic factor (BDNF) and muscle regulatory factors (MRFs), which signal brain stem cells and muscle satellite cells to convert into new neurons and new muscle cells, respectively. This means that exercise while fasting may actually help to keep your brain, neuro-motors and muscle fibers biologically young.

The combined effect of both intermittent fasting and short intense exercise may go way beyond helping you to burn more fat and lose weight; it may help you to:

1. Turn back the biological clock in your muscle and brain
2. Boost growth hormone
3. Improve body composition
4. Boost cognitive function
5. Boost testosterone
6. Prevent depression

This strategy would probably not be appropriate for long endurance exercise, but for the vast majority of casual exercisers, it can be quite beneficial. One of the easiest ways to do this for most people is simply to exercise before eating breakfast, as you’ve been fasting since your dinner the night before.

Read More