In 2017, 56 million people in the United States participated in running, jogging, or trail running, and it’s been a perennial hobbyhorse among fitness enthusiasts for centuries. 

If you’re into running or know people who are, you also know the central role nutrition plays in your performance. 

Runners are bombarded with tips, suggestions, and shibboleths about how, when, and what they should eat. Much of the advice is helpful, some is good but misapplied, and some is facile nonsense. 

Running used to be a major part of my life (I’ve competed in over 100 triathlons and running races), and I know firsthand how confusing it can be to try to make sense of the conflicting advice about how you should eat to get leaner and faster. 

And in this article, we’re going to slaughter some of the most common sacred cows bandied about the world of running. 

Myth #1: Eating Lots of Carbs Is the Most Important Aspect of Nutrition

There’s no question that eating sufficient carbs is important for optimizing your performance and recovery. If you follow a high-carb diet, you’ll have more productive, enjoyable workouts, recover faster from those workouts, and run faster in competition. 

Unfortunately, though, many coaches, authors, and sports scientists beat the drum so loudly for carbs that runners fall prey to the idea that this is the only aspect of a healthy diet. This single-minded focus can sometimes cause them to neglect other vital aspects of nutrition, like eating enough protein.

For example, studies have repeatedly shown that endurance athletes need to consume probably two to three times more protein than the Recommended Dietary Intake (RDI) to optimally support athletic performance and recovery and maintain muscle mass. This is particularly important when restricting calories to lose weight, because you want the majority of the weight you lose to be fat (and not muscle).  

In their pursuit of maximizing their carb intake, many runners also eschew fruits, vegetables, and legumes in favor of bread, pasta, and oats, opening themselves up to nutrient deficiencies. For example, a study published by scientists at Wrocław University found that only 55% of marathon runners consumed the minimum recommended amount of fruits and vegetables.

The lesson? Don’t miss the forest for the (high-carb) trees. 

Eat plenty of carbs, but also get a portion of these carbs from fruits, vegetables, and legumes. 

These foods can enhance recovery and immune function, and they provide much higher amounts of vitamins, minerals, and other phytonutrients than typical endurance athlete fare like pasta, bagels, and so forth. These foods also tend to be much more filling than highly refined carbs, making it easier to lose or maintain weight without being hungry or counting calories. 

A good rule of thumb is to eat three to five servings of fruit and five or more servings of combined vegetables and legumes per day. 

(And if you’d like even more specific advice about how many calories, how much of each macronutrient, and which foods you should eat to reach your health and fitness goals, take the Legion Diet Quiz.)

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Myth #2: You Must Eat Within 30 Minutes of Finishing a Run

Many athletes tie themselves in knots over nutrition timing, and particularly with post-workout nutrition. 

A common belief is that you must eat carbs within 30 minutes or so of finishing a run, or you’ll dramatically impair your recovery. Some people go so far as to say that a run that isn’t immediately followed a post-workout meal is “wasted.” 

Not only is this a major source of anxiety for many runners, it also encourages them to consume large amounts of sugary, highly-processed recovery drinks and bars, which aren’t necessary. 

Luckily, research shows runners can cool their jets—you only need to “restock” carbs within 30 to 60 minutes of working out if you’re going to do another exhaustive lower-body workout (~90 minutes) within about eight hours. Otherwise, you can simply eat normally, and your body will recover and restock glycogen levels just fine.

There’s also much ado made about eating before and during runs, but whether or not this is necessary depends on the length and intensity of your workouts. 

If you’re just going for a moderate 30 to 60 minute run, you don’t need to worry about strategically timing your meals or eating during or after your workout. Eat like you normally would, go on a run when it’s convenient, and don’t overthink it. 

If you’re running for more than 60 minutes or so or doing multiple workouts in the same day, it’s a good idea to eat 20-to-30 grams of protein and 30-to-50 grams of carbs about 30-to-90 minutes before and after your workout (the closer your meal to the start of your workout, the less you should eat to avoid gastrointestinal discomfort). And if you’re exercising longer than 90 minutes, it’s a good idea to eat at least 30-to-60 grams of carbs per hour of exercise (depending on how hard you push yourself). 

Myth #3: Energy Bars, Gels, and Drinks Are Better than Whole Foods 

There’s a widely held belief among many endurance athletes that processed, packaged energy bars, gels, chews, drinks, and so forth are superior to whole foods for fueling workouts. 

While these products can be helpful in certain situations (especially very long workouts or competitions, such as Ironmans), they aren’t necessary in most cases and are often inferior to whole foods. 

One salient example of this comes from a study conducted by Dr. David C. Neiman of Appalachian State University, which found that cyclists who ate bananas during a 46-mile time trial performed just as well as cyclists who slurped sports drinks. Other studies have shown that plain ‘ol raisins are just as effective for boosting endurance performance as energy gels or sports jelly beans. 

What’s more, other research shows that consuming bananas, pears, and other fruits before, during, and/or after endurance training can improve markers of immune function and recovery—something highly-processed sports supplements don’t do.  

The reason for this is that whole foods, and especially fruit, contain large amounts of molecules known as polyphenols, which help reduce inflammation during and after exercise. 

Some of the best high-carb whole foods for fueling your workouts are: 

  • Bananas
  • Pears
  • Apples 
  • Oranges
  • Blueberries
  • Grapes
  • Raisins
  • Craisins
  • Dates
  • Figs
  • Papaya
  • Mango (my personal favorite)

In addition to fruits, other good snacks to eat before or after workouts include: 

  • Yogurt, cottage cheese, or skyr
  • Beef jerky
  • Oatmeal
  • Whey protein
  • Quinoa 
  • Sweet potatoes
  • Kidney beans
  • Chickpeas

Energy bars, drinks, gels, and chews are convenient and tasty, and they can provide some much-needed variety during long workouts, but they aren’t the killer app they’re said to be.

Myth #4: Runners Need to Take Electrolyte Supplements

Sports beverage companies have spent tens of millions of marketing dollars convincing athletes of all stripes that electrolyte supplements are one of the keys to supporting performance and recovery.

Go to Gatorade’s website, and one of the first sentences you’ll see says, “Replenish electrolytes to keep your performance at its peak.”

Their sales pitch goes like this:

When you exercise, you sweat, causing you to excrete molecules like sodium and potassium that carry tiny electrical charges that help facilitate muscle contraction, known as electrolytes. When your body’s stock of electrolytes becomes depleted, your performance drops, and you need to consume more to “keep performance at its peak,” as Gatorade’s copywriters would say. 

What’s more, they claim, a lack of electrolytes also directly leads to muscle cramps, which can quickly kibosh your workouts and competitions.

While this idea is widely accepted by athletes, coaches, and many sports scientists, it’s also scientifically and theoretically bankrupt. 

Allow me to explain.

The keystone of this entire argument is the idea that you lose large amounts of electrolytes (especially sodium and potassium) when you sweat, and that this loss of electrolytes leads to poor performance and muscle cramps.

As exercise physiologist Ross Tucker explains in a series of excellent articles on his website, though, even the “saltiest” of sweaters only lose a small amount of electrolytes when they perspire. In fact, sweat has a much lower concentration of electrolytes than other bodily fluids. 

Thus, when you sweat, the concentration of electrolytes in your body actually rises, because you lose much more water than sodium and potassium. When you drink enough to replenish about 30 to 50% of the water you lose through sweat (about the maximum amount most runners can comfortably consume during hard workouts), your sodium concentrations stay within the normal, healthy range. 

(Oh, and in case you’re curious why runners and other athletes rarely replenish all of the water they lose during workouts, it’s because mild dehydration doesn’t seem to impair performance, whereas overhydration easily can. Guzzling too much water during workouts can also dangerously dilute your blood sodium levels—even if you consume electrolytes.)

What’s more, the concentration of electrolytes in drinks like Gatorade, Powerade, and so forth is so low that it barely moves the needle in changing your body’s electrolyte concentrations. For instance, if a runner loses about two liters of sweat during a two-hour run and only drinks one liter of water, he’ll lose about 4.6 grams of sodium. If he instead drank a sports drink, he’d still lose about 4.2 grams of sodium—hardly enough to make a difference in his performance. 

This was demonstrated in a study conducted by scientists at Pennsylvania State University, which showed that people who drank water or Gatorade during runs wound up with the same blood concentrations of sodium. 

In other words, while you do lose some electrolytes in your sweat, the amounts are too small to matter, and are easily replenished over the course of the day from eating normal foods. 

Even if consuming electrolyte-rich sports drinks and other supplements significantly boosted your body’s electrolyte stores, there’s very little evidence this would stave off muscle cramps. 

Scientists still aren’t sure exactly what causes muscle cramps, but one of the strongest current theories is that they’re the result of “altered neuromuscular control,” not a lack of electrolytes. Basically, there’s a disruption in the electrical signals that cause muscles to contract, which makes them contract too long and at the wrong times. Eating more electrolytes doesn’t fix this, either. 

The bottom line is that you don’t need to take electrolyte supplements before, during, or after runs. Instead, drink water when you’re thirsty during and after workouts and eat a balanced diet, and you’ll have no trouble staying hydrated and maintaining healthy electrolyte levels. 

Myth #5: Getting Leaner Always Makes You Faster

To a point, being lighter and leaner does make you a faster runner, which is why competitive runners and other endurance athletes will always strive to be lean. 

What they need to remember, though, is there’s a point of diminishing returns—you want to be lean enough that you aren’t carrying too much extra body weight, but not so lean that you can’t stay healthy, feel good, and train hard. 

At best, overly restricting your calories will simply enervate your workouts, making you feel sluggish, weak, and slow. At worst, it can lead to an eating disorder.

There’s abundant evidence that people who pursue endurance sports competitively have a higher incidence of eating disorders than normal folks. For instance, a study on elite Norwegian athletes found that about 24% of female endurance athletes and 9% of male endurance athletes had some kind of eating disorder. 

The most common eating disorder among endurance athletes tends to be severely restricting calories to lose weight (which can sometimes morph into full-blown anorexia nervosa). Even athletes who don’t have diagnosed eating disorders (or think they don’t) often overly restrict their calories, which leads to what scientists call low energy availability. 

Basically, these people are eating too little to support their training and other important bodily functions. This, in time, causes high cortisol levels, low sex hormone levels, lethargy, irritability, loss of libido and menstruation in women, a higher risk of injury, and decreased athletic performance. 

Thus, while it is important to get and stay lean if you want to run faster, don’t become obsessed with fat loss at the expense of your performance or health. 

One of the best ways to avoid this problem is to get close to your goal weight long before your most important competition. For example, don’t make the mistake of waiting until a month or two before a marathon to start slimming down. 

Instead, try to be at or within about 5% of your goal weight at least two to three months before your most important competition. This way, you can eat more calories while you do your most intense, race-specific workouts, and can focus entirely on getting faster and staying healthy instead of getting leaner.

Myth #6: Runners Should Never Diet

There are two likely sources of this myth: 

  1. Most runners need to eat substantially more calories than other people, which leads some people to think that they don’t need to follow any kind of structured eating plan. In other words, they can outrun their eating habits.
  2. As you learned a moment ago, some runners do develop an unhealthy fixation on weight loss, which makes many health professionals uncomfortable with the idea of recommending that runners diet.

Both of these ideas are misguided. 

The first point is demonstrably false. Although running does burn a lot of calories, it’s still very easy to overeat and even gain weight while following a vigorous running program. The hundreds of overweight runners training for and finishing marathons bears witness to this fact. Scientific research also shows that simply exercising more without controlling your calorie intake rarely results in meaningful weight loss.

Second, although it’s true that some runners develop an unhealthy fixation with weight loss, this is still a small minority. Most runners are not highly competitive. In fact, many of them run for fun or to improve their health and lose weight. Thus, if someone has a good bit of weight to lose and enjoys running, restricting calories—dieting—can still be a good idea. 

The key is to diet intelligently. 

In general, you don’t want to restrict your calories more than 20% below your total daily energy expenditure (TDEE) when taking part in a vigorous training program (running 20+ miles per week with several intense workouts per week). If you’re following an easier training program, it’s still best not to restrict your calories more than 25% below your TDEE. 

This is typically enough to help you lose weight at a rapid pace without significantly interfering with your workouts or mood. 

(And again, if you feel confused about how many calories, how much of each macronutrient, and which foods you should eat to reach your goals, take the Legion Diet Quiz to learn exactly what diet is right for you.)

Myth #7: You Should Run to “Earn” Your Calories

As a corollary to the last myth, some runners get it in their head that they need to run enough every day to precisely offset their food intake if they want to maintain their trim, lean physique.

If they eat 500 calories more than they normally do, they need to burn 500 more calories running. If they want to eat 3,000 calories instead of 2,700 that day, they better run enough to burn 3,000 calories, and so forth. 

The first problem with this idea is obvious: It’s stressful and sets you up for exercise addiction, eating disorders, and overuse injuries. It also encourages people to build their training plans around the goal of burning calories, not necessarily getting fitter and faster. That is, while moderate-pace, long runs are good for burning calories, they aren’t sufficient for maximizing your performance. 

The second problem with this idea is that micromanaging your calorie intake in this way is complicated, inaccurate, and unnecessary. Although you can estimate how many calories you burn with reasonable accuracy, you’re never going to be 100% correct. Thus, fretting over whether you should burn an additional 100 calories to make up for the banana you had with lunch is a fool’s errand. 

And even if you could perfectly estimate how many calories you burn from exercise, you still wouldn’t need to eat this exact amount every day to maintain your current weight. So long as you’re eating and exercising roughly the same amount every week and maintaining your weight, there’s no need to adjust your food intake to your activity levels on a daily basis. You’ll eat more calories than you burn on some days, fewer on others, and the differences will average out by the end of the week. 

A good rule of thumb here is to track your weight and calorie intake for two weeks to see how much you need to eat to maintain your weight. If your weight goes up, slightly reduce your calorie intake. If it goes down (and you want to maintain your weight), eat slightly more. And if it stays the same, then keep eating the same amount. 

If you want to lose weight, subtract 20% from this number (so you’re eating about 80% of what you need to maintain your weight). 

You don’t necessarily have to count calories to do this—you can simply estimate the calorie content of a few foods and replace those with lower calorie options to achieve this 20% reduction. Then continue training as you were before and tracking your weight to see how your body responds. 

Scientific References +