Frequently Asked Sports Nutrition Questions

author : Nancy Clark
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Time and again, athletes repeatedly ask questions about sugar, protein, supplements, caffeine, carbs, recovery, and body fat. These answers will help you resolve confusing nutrition issues.

The Athlete’s Kitchen
Copyright: Nancy Clark MS RD CSSD

Time and again, athletes repeatedly ask questions about sugar, protein, supplements, caffeine, carbs, recovery, and body fat. To address these issues, an international group of sports nutritionists (Professionals in Nutrition & Exercise Science (PINES); ) gathered in Seattle in May. Experts in their fields discussed the latest research and answered commonly asked questions. Perhaps the answers will help you resolve confusing nutrition issues.

Q. Is pre-exercise sugar harmful to performance?
A. More than 100 studies indicate consuming sugar within the hour pre-exercise does not hurt performance. The vast majority of athletes can enjoy pre-exercise sweets for a quick fix. But some athletes are, indeed, “sugar sensitive” and experience rebound hypoglycemia. They quickly learn—

  1. to avoid sugar 15 to 45 minutes pre-exercise and instead consume it right before they exercise (the body will not have time to release the insulin that contributes to the “crash”) or

  2. choose pre-exercise foods that do not produce a “sugar high” such as oatmeal or whole grain toast with a little peanut butter.

Q. How can I gain muscle and lose fat?
A. It’s difficult for the body to build muscle and lose fat at the same time. Building muscle requires calories. If you are restricting calories to lose undesired body fat, your body does not have the fuel it needs to create new muscle tissue. Instead, the body breaks down muscle to use for fuel.
A dieting athlete can minimize muscle loss with—

  1. a small calorie deficit that contributes to slow fat loss.

  2. an adequate protein intake (i.e., some protein at each meal).

  3. frequently eaten meals that offer a constant supply of protein and fuel.

  4. strength training to help protect against muscle loss.

Q. What should I eat to recover after exercise?
A. After a moderate workout, you need not worry about rapidly refueling because your muscles are not depleted. But if you have done exhaustive exercise, you should plan to replace carbs, water and sodium as soon as tolerable—particularly if you will be exercising again within 6 hours. Adding a little protein to the recovery meal or snack helps repair damaged muscle, reduce soreness, and also enhance glycogen replacement in athletes who neglect to eat enough carbs:

  • For a 150-pound athlete, the recommended carb dose for rapid recovery is ~300-calories every 2 hours for 4-6 hours.

  • A wise protein target is about 15 to 30 grams protein for a 150-lb athlete, taken right after (and/or during) exercise.
    (More precisely: 0.5 g carb/lb and 0.1-0.2 g protein/lb)

Simple suggestions include 16-ounces of chocolate milk; a handful of pretzels and a yogurt; a meal such as cereal with milk, Carnation Instant Breakfast, or a shake made with milk, powdered milk and a big banana or other fruit.

Timing may be more important than the actual amount of food consumed. Your best bet is to time your meals to your training, so you eat a meal after a hard workout.

Q. What's best to drink during and after exercise? How much?
A. Beverages that include a little sodium (i.e., sports drinks) enhance fluid retention. Alternatively, pre-exercise, you can consume sodium-containing foods (salted oatmeal, pretzels, broth). How much you need to drink depends on how much sweat you lose. Weigh yourself pre- and post exercise; dropping one pound equates to losing 16 ounces of sweat that needs to be replaced. More simply, you can monitor your urine and drink enough to urinate a pale-colored urine frequently throughout the day. Not urinating for several hours post-exercise is bad: dehydration!

Q. What should I take to boost my immune system?
A. Moderate exercise actually boosts your immune system; moderate exercisers have no need to take immune-boosting supplements. Hard, exhaustive exercise, in comparison, contributes to inflammation, oxidative stress, and immune dysfunction. But if you are healthy, well fed, and well rested, your immune system can handle the stress. Supplements will not boost your immune function above normal levels.

If you under eat and fail to consume adequate protein or carbs after exercise (as happens with dieters or athletes who are “too busy” to eat), immune response drops. The best supplement to take to counter this response is adequate food—carb-protein combinations, like chocolate milk or a meal.

Quercetin (a bioactive compound found in red apples) is touted to boost the immune system. However, research suggests quercetin works best in “cocktails,” the way it naturally come in foods. That is, a quercetin supplement, by itself, is less effective than when quercetin is combined with other bioactive compounds, such as fish oil and green tea extract.

Q. Should I train on a high fat diet to enhance fat-burning?
A. By burning more fat, athletes are able to burn fewer carbs and thereby spare their limited glycogen stores. Supposedly, this should enhance endurance, given that glycogen depletion is associated with fatigue. Yet, the practice has yet to translate into improved performance. The best way to enhance endurance is to consume carbs during extended exercise.

Q. Should I train with low glycogen stores, and then compete when carbo-loaded?
A. While the “train low, compete high” method is an interesting concept, research has yet to prove it will enhance performance. Theoretically, training “low” stimulates physiological adaptations that spare muscle glycogen and allow greater endurance. The problems are

  1. athletes are unable to train at a high intensity when their muscles are glycogen depleted and

  2. training with glycogen-depleted muscles increases the risk of injury.

Bottom line: Eat carbs daily for well-fueled muscles that allow you to train hard!

Q. What dose of caffeine is best to enhance performance?
A. Although responses to caffeine vary greatly from person to person, a suggested dose equates to a 12-oz. mug of coffee one hour pre-exercise. (More precisely, consume 1.5 mg caffeine per pound of body weight (3 mg/kg)—or about 225 mg for a 150-lb athlete. Higher doses of caffeine offer no performance advantages and can create the disadvantage of sleep problems that end up hurting performance. Enough is enough; more caffeine is not better!

Q. Do I need to worry about contamination in commercial sports supplements like protein powders?
A. Yes! A survey of 634 nutrition supplements indicates about 15% included a banned substance, even though the supplement came from a factory that did not even manufacture banned substances (i.e., steroids, ephedrine). The contaminants make the products “work” (read that, “sell better”). The products most likely to be contaminated with illegal compounds include bodybuilding supplements and weight loss products. Buyer beware!

Q. Where can I find a sports dietitian to help me eat to win?
A. For a board certified specialist in sports dietetics (CSSD) in the US, use the referral network at With a personalized eating program that optimizes your fueling practices, you’ll gain a winning edge!

Nancy Clark, MS, RD, CSSD (Board Certified Specialist in Sports Dietetics) counsels both casual and competitive athletes in her private practice at Healthworks, the premier fitness center in Chestnut Hill MA (617-383-6100). Her Sports Nutrition Guidebook, and food guides for marathoners, new runners, and cyclists are available via See also


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date: July 9, 2009

Nancy Clark

Nancy Clark, MS, RD, an internationally known sports nutritionist and nutrition author, is a registered dietitian (RD) who specializes in nutrition for exercise, health and the nutritional management of eating disorders.

avatarNancy Clark

Nancy Clark, MS, RD, an internationally known sports nutritionist and nutrition author, is a registered dietitian (RD) who specializes in nutrition for exercise, health and the nutritional management of eating disorders.

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