The Protein Push

From the hottest movie star to your next door neighbor, everyone seems to be losing weight on low-carb diets. But will they work for athletes?

By Laura Smith

Laura Smith is an Assistant Editor at Training & Conditioning.

Training & Conditioning, 13.6, September 2003,

For decades, sports nutritionists have been preaching the same message: To fuel working muscles, athletes need to get the majority of their calories from carbohydrates.

Lately, though, carbohydrates’ reputation has taken a hit as a new message has been gaining volume: Carbohydrates make you fat.

No one can blame student-athletes for being confused, but what do they really need to know about finding the optimal nutritional balance? And how can you help them separate out the messages that pose risks to their health and performance?

Hoards of American dieters are taking carb-bashing to heart, gobbling up 10 million copies of low-carb guru Dr. Robert Atkins’ New Diet Revolution since its release in 1992. Models and celebrities continue to add themselves to the list of those attributing their million dollar-physiques to cutting carbs, and a dizzying array of “low-carb” products compete for space on supermarket shelves.

For some people, a diet that limits carbohydrate intake may be appropriate. “Very-low-carbohydrate diets were designed for people who are obese and have insulin resistance,” says University of Arizona Nutrition Counselor Gale Begeman, RD, CSCS. “They were not designed for a population of college athletes.”

Insulin resistance is a reduced sensitivity to insulin that causes difficulty transporting glucose from the blood into cells to be used as energy, and can eventually lead to Type II Diabetes. “Student-athletes, even ones who wants to lose five pounds, are incredibly unlikely to have insulin resistance,” Begeman explains. “Their glucose uptake is going to be fantastic, just by virtue of their high activity level … these diets were designed for people who are very overweight, which is also extremely unlikely for a student-athlete.”

But student-athletes are certainly not immune to the marketing. “Student-athletes see their peers losing weight fast on low-carb plans, and they want to try them too,” says University of Arizona Assistant Athletic Trainer Matt Radelet, MS, ATC, CSCS. “Along with wanting to lose weight to perform at their best, there are powerful social pressures to look a certain way, especially for women in this age group, and that can add up drastic dieting.

“Over the past year or so, it’s become tough to combat the messages they’re getting,” he continues, “but it’s critical that we educate athletes about the risks.”

Those risks can be both short and long term. A diet that severely shortchanges athletes on carbs saps their muscles of needed glycogen, compromises their performance, and can lead to health problems.

“Carbohydrates are the primary source of fuel for working muscles,” Begeman explains. “Athletes trying to eat very-low-carb diets are taking away their primary fuel and making their bodies jump through additional hoops. They’re at greater risk for losing lean mass. I tell them, ‘Sure, you may lose some weight—you’ll lose some water and some muscle—weight you didn’t want to lose.’”

“A very-low-carb diet is not going to give them the energy they need, so they’re not going to make the strength gains they need to perform at their best,” agrees Susan Nelson Steen, ScD, RD, Director of Sports Nutrition for the University of Washington athletic department. “By limiting their carbohydrates, they’ll limit their glycogen stores, which will limit their ability to exercise at a high intensity. And if they can’t train at a high intensity, they won’t be able to perform at a high intensity. In addition, they’ll be more prone to injury because they’re fatigued.”

The long-term health consequences are just as damaging. “The biggest danger is that if you’re eating all protein, you’re cutting out foods like bagels, bananas, and breads,” says Nancy Clark, MS, RD, nutrition counselor at SportsMedicine Associates in Brookline, Mass., and author of the best-selling Nancy Clark’s Sports Nutrition Guidebook. “This means you’re not getting enough fiber or cancer protective phytochemicals. Every major medical association recommends fruits and vegetables and whole grains as part of a healthy diet—and those contain carbs. To eliminate them is counter to a plethora of health wisdom.

Caroline Hodges, RD, Nutrition Counselor at the Elmira (N.Y.) Nutrition Clinic, who works with Cornell University student-athletes, finds that eating-disordered athletes can be particularly susceptible to the low-carb message. “Athletes with an underlying eating disorder are the most likely to want to severely restrict carbs, and that is a huge concern,” she says. “Eating-disorder patients are typically very sensitive to serotonin level changes, and because serotonin is a byproduct of carbohydrate metabolism, a low-carbohydrate intake depletes the serotonin levels in the brain. With lower serotonin, these athletes become more depressed and more obsessed, and that makes their eating disorder worse.”

While there’s near-universal agreement that severely restricting carbohydrates is a bad idea for athletes, exactly where to draw the line is less clear. Most nutritionists believe that there is no one-size-fits-all answer. The athlete’s sport, position, and the level of training intensity all have to be taken into consideration.

Sports nutritionists have traditionally advocated a diet that takes 65 percent of its calories from carbohydrates. Some have revised their message to between 50 and 65 percent depending on the particular demands an athlete is placing on his or her body, and a handful are recommending 40 percent for specific athletes. Almost all agree that going lower than 40 percent is a recipe for trouble.

“I recommend 55 to 65 for most athletes,” Nelson Steen says. “But I can go as low as 50 percent, depending on their sport and what they’re doing. It’s possible, for example, that a 300-pound lineman who is working to decrease body fat could actually be insulin resistant. In that case, a diet that’s 65 percent carbs wouldn’t be a good idea.”

The higher the frequency and intensity of an athlete’s aerobic output, the better his or her ability to handle the insulin spikes that carbs trigger. “That’s why it’s really important to look at each sport and each position within each sport individually,” Nelson Steen explains. “Certain positions on the football team do very little aerobic work, but others are actually more similar to the energy output you’d see in a basketball player,” she continues. “Even the type of strategy a team has makes a difference. If you’ve got a running game and one individual you are constantly keying in on, that athlete is going to need a higher percentage of carbohydrate to replace the glycogen they’re sapping from their muscles.”

Begeman’s recommendations for her student-athletes range from 50 to 70 percent of calories coming from carbohydrates. “I can go a little bit below 50 percent in very special cases, but I’m more comfortable at 50,” she says. “They really need that carbohydrate to fuel whatever they’re doing, whether it’s strength or endurance.”

David Ellis, RD, LMNT, CSCS of Sports Alliance, Inc., suggests that athletes may need a range of carbohydrates, depending on their activity level on a given day. “An athlete may need anywhere from 40 to 60 percent of calories from carbohydrates depending on whether it’s an active or an inactive day,” he says. “They’ll have less potential to dispose of extra sugar and fat calories on inactive days.”

Nelson Steen also focuses on a solution that doesn’t get caught up in the numbers. “Deciding whether an individual has gone too low-carb by assigning specific numbers is tricky, because eating isn’t that exact and student-athletes run the gamut in terms of what they need,” Nelson Steen says. “It’s best to evaluate how they’re feeling and how they’re performing. If they’re fatiguing really quickly and not performing well, they’ve crossed that line.

“Another red flag is if they say they’re not thinking as clearly,” she continues. “We tend to forget that carbohydrates have an effect on the brain and on how clearly we can think. Glucose is the primary fuel for the brain, so an athlete who’s not taking in enough carbs will be irritable, tired all the time, sleeping more, and not as mentally focused. At that point, it’s time to up the carbs.”

But what can you do when an athlete is set on trying out a low-carb diet? The best approach is to ask them to first examine the type of carbohydrates they are consuming.

Many college-age students consume a lot of empty calories. If athletes can recognize which of their carbohydrates are coming from refined sugars and replace them with healthier carbs, both weight loss and increased energy will follow.

“When we tell athletes ‘high carb,’ they tend to hear ‘high sugar,’” Nelson Steen says. “I think the best message is, ‘It’s important to eat sufficient carbohydrates, but you’ve got to think about the kinds of carbohydrates you’re eating.’”

“Student-athletes tend to get an overwhelming amount of sugar in their diets,” Clark agrees. “It’s important that we educate them about the fact that carbs come in many different categories, and they aren’t all created equal. You have fruits and vegetables and whole grains, which are very health-promoting. Then you have Twizzlers and Big Gulp sodas, which is the logical category for an athlete to limit.”

Even foods that don’t appear sugar-laden can be replaced with more nutritious carbohydrates. “They may not be eating chips and cookies, but they may be living on white bread, bagels, and cereal,” says Begeman. “If that’s the case, they probably don’t realize how many calories they’re taking in, and that could be the source of the unwanted weight.

“Cutting back on simple sugars will facilitate weight loss without sacrificing energy, so I advise them to make some substitutions,” she continues. “Instead of two big bowls of cereal, how about whole wheat toast with peanut butter and a cup of yogurt or some scrambled eggs? The traditional bagel with cream cheese packs 500 calories. Instead, they can have a piece of fruit and yogurt, a slice of whole wheat bread, and a soft-boiled egg for fewer calories than that one bagel. They’re always amazed when I point that out.” For more examples, see “Power Switches” below.

It’s not only the quantity and quality of carbohydrates that matter for student-athletes. Timing is another key piece of the puzzle. In order to fuel themselves for their activity and then recover, athletes need to be eating carbohydrates throughout the day.

“With their crazy schedules, that issue can become even more important than numbers and percentages,” Nelson Steen says. “I tell our student-athletes they need to be grazing. It’s really important to help them build frequent meals and snacks into their busy schedules because they’re constantly going through the cycle of getting fuel to exercise and then recovering from exercise.”

“Many of my student-athletes say, ‘I don’t have time to eat before I work out,’ or ‘I put it all off until 2 in the afternoon,’” Begeman says. “I tell them, ‘When in doubt, eat anything, but make sure it’s throughout the day. From there, we can talk about exactly what you’re eating.’”

Along with eating carbs throughout the day, nutritionists have suggestions for the time immediately surrounding practice. Pre-exercise, student-athletes need foods high in carbohydrates along with some protein, Begeman says, and during practice, she suggests a small amount of a high-carb food. After practice, she urges a larger portion of a high-carb food. “It’s important for them to eat their post-workout carbs within 15 or 30 minutes, because there is an enzyme active in their bodies at that time that encourages glycogen repletion,” she says.

Nutritionists are also recommending that post-workout meals and snacks contain small amounts of protein. Studies show that the amount of protein required to boost recovery is about 6 grams, along with about 35 grams of carbohydrate, Nelson Steen says. However, beware of athletes taking the protein component to an extreme.

“The problem is, student-athletes tend to think, ‘If some is good, more must be better,’” Nelson Steen says. “They may end up having mostly protein and no carb after a work-out, and then they’re losing the opportunity to restore their glycogen. Six grams of amino acid really isn’t much.”

In giving athletes the best advice about carbohydrates, it’s key that everyone is on the same page. That’s why it’s important to educate all athletic trainers on staff about the topic.

“Athletic trainers face two problems when it comes to this issue,” Begeman says. “One, they may not feel completely confident with the information, and two, they don’t usually have time to educate themselves and their athletes on it. Asking the nutritionist to do an in-service with the athletic training staff can go a long way toward getting rid of misinformation.”

It’s important to get coaches on board as well. “A lot of coaches are susceptible to the low-carb marketing campaign that’s so prevalent in the popular media,” says Radelet. “We’ve got coaches telling athletes, ‘You need to go on the Atkins diet.’ Communication between athletic trainers, nutritionists, and coaches can prevent that from happening.”

Getting your athletes to understand the science can be done through workshops, handouts, and individual counseling. The key is making the information easy and convenient.

“I try to give them very practical strategies,” Nelson Steen says. “I give them recipes and quick, easy ways they can get fuel so they can feel better during practice and make the strength gains they need for their sport.”

Begeman posts handouts on her department’s Web site ( listing “one-minute snack ideas” broken down into three time periods: before practice, during practice, and after practice. She focuses on inexpensive, high-quality carbohydrates that student-athletes can keep nearby in their lockers or backpacks.

Knowing what’s in your school’s cafeteria can be another great way to help student-athletes choose healthy carbs throughout the day, says Nelson Steen. “I have listings of foods that are in every dining hall and eating area, so we can talk about what their actual choices are,” she says.

Begeman is taking things one step further this year. “Right now I’m writing a nutrition guidebook that’s specifically designed for student-athletes on the University of Arizona campus,” she says. “It’s meant to be a hands-on manual so athletes can flip it open and find out, ‘What kind of food do I need, and where can I get it here on campus?’”

University of Arizona student-athletes will each get a copy of the booklet at their preparticipation physicals this fall. “At other schools where this has been done, student-athletes have said they carry the books with them because the advice is so easy to use and it allows them to get the fuel they need on campus,” Begeman says.

Even if your educational efforts cannot include guidebooks, you can still inform your athletes with a simple message. “It’s all about balance,” Nelson Steen says. “The next extreme diet they come across may look attractive, but it’s up to us to arm them with the information to choose reasonable behaviors that are going to be best for their health and their performance.”

When trying to get athletes to improve the quality of the carbohydrates they’re eating, it’s important to give them actual substitutions. University of Arizona Nutrition Counselor Gale Begeman, RD, CSCS offers her athletes a handout listing “power switches” to help them replace high-sugar snacks and meals with healthier carbohydrates and protein in every area from beverages to fast food. Here is a sample:

Instead of: soda, punch, lemonade, beer, frapacchino
Switch to: water, caffeine/sugar free soda, orange juice, apple juice, cranberry juice, V8, milk, chocolate milk

Instead of: chocolate bar, sandwich crackers, potato chips, tortilla chips, ice cream, buttered popcorn
Switch to: fruits, vegetables, whole-grain crackers, light popcorn, pretzels, baked tortilla chips

For more samples, go to, click on Online Library, click on Nutrition, and click on Sports Nutrition.

One of the best ways to steer weight-conscious athletes away from diets dangerously low in carbohydrates is to offer tips for a healthy alternative plan. First, it’s important to encourage theme to restrict weight-loss efforts to the off-season.

“The first thing I tell them is, ‘Don’t try to lose weight during your season, or you will end up decreasing your performance,’” says University of Arizona Nutrition Counselor Gale Begeman, RD, CSCS. “It’s a difficult message to get across, because during their season is exactly when they are under pressure to improve, and they think that they can do that by losing weight. But to lose weight, they have to create an energy deficit, and that really risks decreasing their performance.”

Then, instead of restricting carbs, Begeman offers other suggestions. “I tell them to get very tight with the quality of the foods they’re eating, reduce their calories, and depending on their sport, consider increasing the aerobic work they’re doing,” she says. “Athletes in power sports who want to lose fat may think they’re getting a lot of exercise, but they may actually need to get more cardio output going.”

Begeman also cautions against trying to lose weight too quickly. “If an athlete chronically over-restricts their calories, the body can over-ride it for a while and get the work done,” she explains. “But they will eventually fall apart, because they can never fully recover until they re-fuel themselves.”

Encouraging athletes to consider their body composition rather than their weight is another way to promote healthy eating. “Body comping is always my preference, instead of looking at a number on the scale,” says Caroline Hodges, RD, Nutrition Counselor at the Elmira (N.Y.) Nutrition Clinic. “It can be very helpful with athletes who think they need to lose weight, because it gives them accurate information about exactly where they are.”

Often, a closer look can reveal that an athlete’s weight is fine where it is. “If an athlete believes they should lose weight, I first ask them, ‘Okay, why do you need to do that?’” says University of Arizona Assistant Athletic Trainer Matt Radelet, MS, ATC, CSCS. “‘Are you saying that because your performance has dropped off and you think there is a connection? Or are you just saying that because you’ve gained a few pounds over the season?’ If we can’t make a connection between performance and the need for weight loss, we have to seriously ask why they think they need to lose weight.”