5 Nutrition Mistakes Athletes Make

Do any (or all) of these common nutrition mistakes sound familiar? Read on to learn how to avoid them for good and improve your athletic performance! 

*Note: I'm a certified strength coach, but not a registered dietitian. 

1. Ditching Carbs

The popularity of paleo, pure-protein, and ketogenic diets in recent years has pushed carbohydrates to the dietary margin of the American plate. These high-fat, high-protein diets claim to promote fat loss in subjects, as the body shifts from carbohydrate to fat as its primary fuel source when depleted of carbs for a long enough period of time. Since athletes need more daily protein than non-athletes—to help the body repair itself after hard workouts and build new muscle tissue—it’s easy to see how some athletes get caught up in these low-carb eating plans. But if you’re a serious athlete, ditching carbs entirely can be harmful to your performance and your health.

“The human body can only generate a certain amount of muscle tissue at a given time,” says sports nutritionist and Clemson strength coach Mike Bewley. “Any protein consumed over and beyond the body’s muscle-building requirements will simply get used for energy or converted into body fat.” This means that eating tons of protein in order to lose body fat can still be stored as body fat anyway! Plus, “Protein [is] a very expensive source of fuel, because it takes the body great effort to break it down into usable glucose for energy,” says Bewley, whereas fats and especially carbs are high-grade fuel for performance. Carbs provide a faster fuel source that can be used immediately for intense exercise, and help the body recover and repair after exercise (especially when ingested along with protein), and therefore is key to athletic success. Conclusion? Eating a balanced diet, complete with carbohydrates, is the best way for athletes to fuel performance.


  • Aim to get your carbs first from fruits and vegetables, then from whole-grain food sources like oatmeal and rice
  • Avoid “empty carbs” that come from processed foods like chips, crackers, and candy
  • If you do need to lose body fat, reduce your daily caloric intake by no more than 500 calories per day (to avoid losing muscle and affecting your athletic performance)


2. Getting All Your Calories From Crap

Getting enough calories to fuel your activity is the most important dietary goal—but getting your calories from the right foods is arguably just as important, especially when we’re talking about athletic performance. After all, I think it’s pretty safe to assume that you’re going to feel and perform differently after eating a bowl of oatmeal with blueberries than you will after a bag of Flamin’ Hot Cheetos (I just feel red-handed regret). Foods that contain high levels of refined sugars, saturated and trans fats, and chemical preservatives may help you meet your caloric needs of the day, but may not help you perform your best on game day. Plus, when you fill your diet with whole foods like fruits and vegetables, you get the bonus of fiber, vitamins, minerals, and water content to help keep you hydrated and energized during exercise.

Most athletes know they should be getting the majority of their calories from unprocessed, whole foods—but trying to juggle classes, work, and a social life along with your training and sport schedule can make choosing quality foods nearly impossible. Convenience wins out, in the form of pre-packaged meal bars and vending machine options, more often than not. And let’s face it: there are always going to be those days when no amount of planning can help you avoid that 3pm Snickers bar. But there are some small changes you can make to help you prepare for those moments and front-load your diet with good choices.


  • Pack whole foods—fresh or dried fruits, vegetables, nuts/seeds—for quick on-the-go snacks
  • Aim to get at least 1 serving of veggies at every meal, even if it means a Big Mac with a side of broccoli from home
  • Scoop protein powder into a shaker bottle for an easy post-workout snack/meal
  • Packets of oatmeal are easy to transport, and you can find hot water available many places—try for unflavored or low-sugar varieties
  • Hard-boil a carton of eggs at the beginning of each week for an easy, portable snack (just don't unwrap during class and alienate everyone with your egg smell)
  • If you do end up at a vending machine, choose the least processed option (like nuts) or high-protein items (like protein bars) over chips and candy


3. Not Drinking Enough Water

Under-hydration is probably the #1 nutrition mistake we see athletes making on a regular basis. After all, “Water is the most important nutrient for the human body,” says the NSCA’s Guide to Sport and Exercise Nutrition (71). Dehydration, especially during exercise in hot environments, can lead not only to decreases in athletic performance but also heat-related illnesses, including the potentially life-threatening heatstroke. Water is crucial for normal cardiovascular function and thermoregulation (your body’s ability to regulate its temperature and prevent overheating), and if you’re an athlete, it’s also critical to your performance (74).

Why is water so important? During exercise, your body’s core temperature rises, increasing blood flow to your skin and causing you to sweat in order to cool your body down. In athletes, the major cause of dehydration is failure to replenish fluids lost through sweat. While many different factors influence hydration levels during exercise—environment, clothing type, equipment worn, the athlete’s metabolic rate, etc.—it only takes a loss of just 2% of your body weight through sweat to start seeing a decrease in your athletic performance (78). For athletes who have larger body surface areas (like American football linemen), wear heavy protective equipment (like ice hockey players), or engage in dehydration practices in order to make a weight class (like wrestlers), the risk of dehydration—and performance decrements—is even greater.


  • 4 hours before exercise, aim to drink about 5-7 ml of fluid per kg of body weight (that’s about 12-16 oz for a 150-lb athlete)
  • 2 hours before exercise (if you’re not urinating or your urine is dark), drink 3-5 ml of fluid per kg of body weight (7-12 oz)
  • During exercise (lasting longer than 60-90 min), aim for 3-8 oz of a carb-electrolyte beverage every 10-20 min
  • After exercise, the goal is to fully replenish any fluid deficit—aim to drink 20-24 oz of fluids for every lb lost during exercise


4. Drinking Too Much NON-Water

From Bo, one of Volt’s Strength Coach Consultants, who played baseball at Pacific Lutheran University: 

“Once, during my sophomore year of college, I consumed 15+ energy drinks during midterm week to help me stay awake studying. In the seventh inning of our game that week, BOTH of my hamstrings started cramping…while I was in the on-deck circle. I wasn’t even playing—just warming up! The game was literally halted because I was sitting down on the field and couldn’t stand up to walk back to the dugout.”

Just as not drinking enough water can be harmful to your athletic performance, drinking too much OTHER stuff can do the same. Energy drinks, alcohol, soda, coffee, sugary sports drinks—all can lead to dehydration, especially if you drink these substances in place of good old-fashioned water (right, Bo?). And while the stimulating effects of caffeine and sugar can create a temporary spike in heart rate and blood sugar, respectively, leading to some performance enhancement, consuming too much of these substances can cause headache, dizziness, upset stomach, restlessness, and more.  Also, many of these beverages are highly caloric, making them detrimental to athletes needing to maintain or optimize body composition for competition (like wrestlers).

Bo says, “My dad was listening to the game on the radio and heard the announcer say, ‘Well that’s the first time I’ve ever seen someone get hurt in the on-deck circle!’” Don’t be like Bo and neglect your water intake in favor of non-water beverages—he learned his lesson.


  • Aim to drink water first, and other beverages only after you’ve gotten enough water to keep you hydrated
  • Alcohol leads to dehydration and a loss of mental sharpness—avoid on competition days (or, better, all sports season) for best results
  • Love your morning coffee? Stick to 1-2 cups max and limit any added sugar or flavorings
  • If you do decide to consume non-water beverages, make sure to adjust your daily caloric intake to account for the added calories


5. Eating For Looks, Not Performance

It’s so easy to get caught up in the aesthetics of working out and competing. Because let’s face it, when you train really hard, you tend to (depending on your sport) develop more muscle, lose body fat, and achieve a more “athletic” body type—which is arguably the most culturally appealing body type of the 2010’s decade. But looking good should be a secondary perk to athletic training, not a primary goal—and your diet should follow suit. While biceps curls may get your guns beach-ready, they won’t necessarily make you a better athlete—and the same is true for under-eating, over-exercising, and fad diets.

You need balanced nutrition to feel and perform your best, including enough calories to support your daily activity. For many athletes, especially athletes in sports that require precise body composition or weight to compete, the pressure to succeed in competition and a drive for perfectionism can create disordered thinking and eating.

A former college women’s lacrosse player shared with me that there were girls on her team who would run constantly—before and after practice, on game days, all the time—in order to maintain a low body fat percentage. Another player lost 15-20 lbs over the summer, only to find she was weaker and less powerful on the field, and easier to push around defensively. Another player struggled with anorexia. The drive to succeed, to perform, and to fit into a perceived “ideal” body type can cause athletes to not eat enough to support their activity, increase their activity in order to burn more calories, and/or adopt disordered eating patterns or fad diets (like paleo) to try and change their bodies. But the irony is that these habits, more often than not, will lead to exhaustion, decrease in athletic performance, and injuries.

The beauty of sports is that it can teach you to appreciate your body for what it does, and not just what it looks like. Feeding your body the right fuels for your activities will help you perform better—and feel better.


  • If you create too great a calorie deficit through under-eating, your body may utilize your muscle tissue for fuel—so eat enough to prevent muscle catabolism!
  • Muscle tissue takes a lot of calories to maintain—thank those bad boys and fill up your plate, you need it!
  • If you do need help reaching the right body composition for your athletic goals, try decreasing your daily caloric intake by up to 500 calories per day—this will help you avoid performance decrements
  • If you struggle with body image issues, consult a psychologist who can help—many schools even offer counseling to students for free!
  • Visit the National Eating Disorders Association website for a toll-free helpline to call and other resources!


Got Any Nutrition Mistakes We Missed?

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Christye Estes, CSCS, is one of the regular contributors to the Volt blog. She is an NSCA-certified strength coach and a Sport Performance Specialist at Volt.
Learn more about Christye and read her other posts | @CoachChristye