Carbs, Protein & Performance

Photo courtesy of Pink Sherbert

These are just a few of the questions addressed at the 27th annual meeting of SCAN, the Sports And Cardiovascular Nutritionist’s practice group of the American Dietetic Association. Over 400 sports dietitians gathered to learn the latest news from prominent sports nutrition researchers. I hope this information will help you choose a winning sports diet.

Carbohydrate Update

Louise Burke, PhD, Director of Sports Nutrition at the Australian Institute of Sport, addressed the following questions:What are the best percentages of carbohydrates, protein, and fat for a sports diet: 40-30-30 or 60-25-15?

Neither! A better approach is to define nutrient needs in terms of grams per kilogram (or pound) body weight. For example, the International Olympic Committee developed these guidelines:

How much should I eat during long runs?

--During long runs that last 1 to 2.5 hours, you want to target 30 to 60 grams of carbohydrate (120 to 240 calories) per hour. That’s about 1 to 2 gels or 16 to 32 ounces of a sports drink per hour (after the first hour, if you ate a pre-run meal or snack).

--During runs longer than 2.5 hours, consuming 60 to 90 grams of different sources of carbohydrates (such as sports drink, banana, gummy candy) per hour is appropriate, as tolerated. Consuming the higher end of the range (90 g, as compared to 60 g) is associated with greater stamina and endurance.

How long does it take to refuel from a long, hard training run?

If you eat a carb-rich sports diet, you can replenish depleted glycogen stores in 24 to 36 hours post-exercise (with no running during that time). While it's important to pay attention to your recovery diet, most runners do not need to eat immediately after exercise unless they are doing double workouts. (Soon after exercise, yes; immediately, no.)

What can I do if I cannot tolerate any food during a long run?

Try mouth swishing with a sports drink. This sends a message to the brain that energy is forthcoming and you’ll feel more energetic. Swishing can enhance performance by 2% to 3% if you are exercising on empty and have not eaten pre-exercise—as often happens with morning runners. (Swishing seems to be less beneficial after a pre-run meal; more research is needed to verify these findings.)

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Protein Update

Stuart Phillips, PhD, professor of kinesiology, McMaster University in Ontario, Canada answered these questions -

Do runners need more protein than non-athletes?

While the recommended protein intake for the average American is 0.4 gram protein per pound body weight (0.8 gram protein per kg), most exercise scientists agree that athletes need a more to optimize muscular development: 0.5 to 0.8 grams protein per pound (1.2 to 1.7 grams of protein per kilogram) body weight per day.

However, most active women and men generally consume about 0.55 to 0.65 g protein/lb (1.2 g and 1.4 g protein/kg) body weight per day, respectively. They can appropriately meet their higher need without supplements.

How much protein do I need after I lift weights?

Consuming 20 grams of protein-rich food (Greek yogurt, tuna sandwich, 16 oz. chocolate milk) after resistance exercise is plenty to optimize the rate of muscle synthesis. Runners should then continue to eat protein and carbs at meals and snacks throughout the day. The highest rate of protein synthesis is 3 to 5 hours post-exercise.

This raises the question: Should runners who work out twice a day plan to avoid exercising during that time frame? Remember: The “good stuff” (building muscle) happens during rest and recovery and the “bad stuff” (muscle damage) happens during exercise. Hence, rest is an essential part of a strength-training program.

Should I buy whey protein supplements?

Probably not unless you are a frail, elderly person with a limited food intake. Drinking milk (20% whey, 80% casein) and eating a balanced sports diet can be as effective as whey supplements. Hard, hard work is the basic trigger for stronger muscles!

Copyright: Nancy Clark, MS, RD, CSSD
Nancy Clark's Sports Nutrition Guidebook (2008), Food Guide for New Runners and Food Guide for Marathoners are available at her website.

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