1. Simple sugars during exercise are bad.
Sugar is the most important energy source for intense endurance exercise. Countless studies demonstrate time and again that supplementing your body’s supply of glycogen (which is how glucose is stored in the body) with glucose, fructose, and other simple sugars that are easily converted to glucose during exercise enhances performance in workouts and races lasting longer than an hour. Yet, many athletes avoid using sports drinks and energy gels containing simple sugars because they have been programmed to think “Sugar is bad.” When training and racing, sugar is the most critical and easily accessed fuel source you can ingest.
2. There is an optimal dietary ratio.
Should your diet be 60% carbohydrate/20% fat/20% protein, as many sports nutrition experts recommend? Or should it be 40% carbohydrate/30% fat/30% protein, as other experts contend. Or something else? In fact, science has shown that there is no such thing as a one-size-fits-all optimal dietary ratio.
Individual athletes need different amounts of the three macronutrients based on how much they train. Consequently, requirements vary the most in relation to training volume. The average athlete requires about 2-3 grams of carbohydrates per pound of body weight daily. But if you’re pushing your volume above 20 hours per week, then you may need even more.
3. Eating more fat will increase your endurance.
A currently popular trend among endurance athletes is eating a high-fat diet to increase the muscles’ reliance on fat for fuel during exercise and thus increase endurance by sparing the muscles’ limited glycogen stores. Studies have shown that a high-fat diet does increase the muscles’ reliance on fat for fuel during prolonged exercise, however this has no effect on actual performance.
4. Muscle cramps are caused by dehydration.
This has got to be the most misunderstood and over-hyped myth in the endurance athlete universe. The idea that exercise-related muscle cramps are caused by dehydration and/or electrolyte depletion originated from a single flawed study conducted almost a century ago. More recent science has clearly shown that there is no correlation between dehydration levels and risk of cramping.
While there is a lack of complete consensus on the topic (maybe, in part, due to the prevalence of long-standing myths), muscle cramping instead appears to be a symptom of neuromuscular fatigue caused by excessive exertion. This is arguably the reason why we athletes don’t cramp up in workouts but do cramp in some races. Drinking more fluid and consuming more electrolytes have also not been shown to reduce cramping risk in susceptible athletes in races, with the exception of one study showing that sodium-loading BEFORE prolonged exercise delayed the onset of cramping. Keep in mind that the body has way more sodium and electrolytes stored up in the body than we could ever deplete in a workout or race. So, forcing more down your throat during activity provides you with a higher risk of GI distress and a quick trip to a Port-o-John than with magical anti-cramping powers.
5. Most endurance athletes eat enough carbohydrate.
The low-carb (or high-fat) craze that began in the mid-90s and continued for more than a decade has left the endurance athlete community believing that a diet providing 40-50% of calories from carbohydrates is enough to keep the body’s fuel tank topped off. While a 40-50% carbohydrate diet may work just fine for the “average Joe” or a sedentary person, this is not enough for endurance athletes who burn a lot of calories during their workouts.
As we discussed above (and as I blogged about here), while we cannot pinpoint a one-size-fits-all diet that is correct for every athlete, rather than thinking in percentages it is important to think in absolute amounts. Adjust your target carbohydrate amount based on your body weight and activity level. Runners specifically need at least 2 grams of carbs per body weight daily. Elite athletes may need as much as 5 grams per pound during periods of peak training volumes.
6. Endurance athletes need to eat as carefully as non-athletes.
Many endurance athletes assume they can “get away with” eating a little more junk than couch potatoes can. Sports nutrition experts frequently try to correct this assumption, arguing that saturated fat, sugar, and the rest have the same terrible effects on the body whether you exercise or not. But, in this case, the endurance athletes have it right.
High-volume aerobic exercise does mitigate the negative effects of consuming certain nutrients that are generally labeled as “bad for you”. The license to eat a little more garbage—and to just eat a more period—is one of the great rewards of working out every day. The caveat is that the diet of the average person is typically awful, and exercising definitely does not give you a license to eat poorly. It is still a “garbage in, garbage out” scenario. So, while an endurance athlete can get away with some dietary sloppiness, if you can get your diet right 80% of the time or more, then you can relieve yourself of the guilt factor so many of us are saddled with.