Fitness: Fueling Up on Food for Fitness (cont.)

Do you feel that an athlete's nutritional needs can be met with just diet or do they also need to take vitamin and mineral supplements?

Good question. We've become very fearful of providing supplements to our Olympians, unless we're completely confident of the content of the supplement provided. A number of supplements that have been marketed to athletes in the past were shown to be corrupted by foreign substance that the IOC has deemed to be banned. Therefore, we try as much as is possible to deliver all nutrients to athletes through food alone.

There are, however, certain nutrients that female athletes in particular may find difficult to obtain sufficient quantities of without supplements. Those nutrients are iron and calcium. We pay particular attention to those two when we assess athletes to determine their status and to determine whether a supplement of calcium or iron is needed.

Other nutrients, depending on an individual athlete's dietary habits, may also be low. For instance, zinc status has been found to be marginal in several athletes and if we find that we can't correct this through diet, then we do look carefully at supplement intake. Again, knowing that supplements may well be corrupted, we are very careful of the source.

What formula do you use to determine daily caloric intake (to be "weight stable" as you mentioned)?

Good question. We use a standard metabolic cart to determine resting energy expenditure, and we apply MET values to determine the additional caloric requirement from the activities they are pursuing. That information, coupled with a history of weight stability, helps us understand precisely caloric needs. A MET table contains the metabolic equivalence of different activities. These are multiplying factors of resting energy expenditure. For instance, if someone burns 60 calories an hour at rest, they may burn 1.2 times that much when they're walking slowly.

For the average person, the best way to determine caloric requirement is to assess the total calories currently being consumed over a period of several days and weight over that same period. If the person is weight stable, then total caloric intake is appropriate for their level of activity. If a person is losing weight, then total caloric intake is less than they require to maintain weight, and so on.

When playing hard in the heat, is it important to have something with sodium? My doctor recommended that we have some sports drink to replenish salts when we are out in the hot weather working out. I hate the taste of the stuff. How important is it to replenish salts? Is there anything I can eat that would do the same thing?

The single biggest factor associated with the maintenance of athletic performance is the maintenance of blood volume. Sodium helps to maintain blood volume. In addition, sodium in a sports beverage helps to drive the desire to drink. This is cortically important, because without that stimulation, most athletes voluntarily dehydrate themselves and get a concomitant reduction in performance. Put simply, sports beverages are an excellent means of delivering:

  • Calories during physical activity, which enhances performance
  • Sodium, which helps blood volume, which also helps to sustain performance
  • Fluid, which is necessary to replace the fluid lost from sweat during physical activity
Sports beverages very often don't taste good to people when they're not exercising. They have been developed to have a good mouth feel for people who are exercising. The way beverages taste when you're not exercising and when you are exercising is completely different. I suggest you try several different sports beverages while exercising to find one you tolerate. What a sports beverage delivers is very important for performance.

"The single biggest factor associated with the maintenance of athletic performance is the maintenance of blood volume. Sodium helps to maintain blood volume. In addition, sodium in a sports beverage helps to drive the desire to drink."

I'm only 14 years old, but I was trying to get thinner by doing all these diets. Now I realize I just like to work out. It's more of a hobby now. I like to sweat and just have fun, but the thing is how do I eat to remain healthy and get the energy I need? Sometimes I feel like I eat too much and it's hard for me to play a sport because I'm so full, and then when it gets to be dinner time or just a snack I want to eat but I don't feel hungry. So what should I do to improve on my eating and what should I eat?

You ask a question that's important not just for 14-year-olds, but also for most people. I' m going to give you a little analogy. Imagine you have a car and you're going to drive from Atlanta to New York. You can't tell your car, "I'm going to give you all the gas now before we leave Atlanta," because your car doesn't have a gas tank large enough to hold that much gas. You also can't tell your car, "Please drive me all the way from Atlanta to New York, I'll give you all the gas you needed for the trip once we get to New York." The only way your car will get you to New York is to fill it up to begin with and fill it up every 300 miles until you get to New York.

In a way, you can consider your eating habits the same way. You should be consuming frequently, in small meals, so you don't feel full, often enough so your blood sugar stays stable, and so you can provide enough nutrients for your body to stay healthy for you to have enough energy for you to do your physical activity and for you to grow.

The three-meal eating pattern so many people have today makes it very difficult to not put on weight, because too many calories are being delivered in too few eating opportunities. Try having breakfast, a midmorning snack, lunch, afternoon snack, dinner, and after-dinner snack as a way of avoiding getting too full and to assure that you have all the energy you need to do the exercise or the sports you want to do.

Dan, before we wrap things up, do you have any final words on food and fitness for us?

My final words of wisdom would be: Never allow yourself to get thirsty and never allow yourself to get deep down hungry. Both are sensations that something bad is already happening.

The last word is it would be very nice if all of you would have a group "Go get 'em" for our marathoners. This is the most difficult marathon course in the world. Just to give you an idea of what our athletes are about to do; at the 18 kilometer mark, our athletes will start to climb some hills that are equivalent to climbing up a 5 story building each mile for 7 miles. Once they reach the 31K point, they have to run down a hill at about the same steepness all the way down into Athens until they've gone 42 kilometers. It's a brutal course with the best athletes in the world running it. We've got some real wonderful Americans marathoners who are running this course -- the women on the 22nd of August and the men as the last event of the Olympics on the 29th. Please wish then well!

We will!

Our thanks to Dan Benardot, PhD, RD, LD, for joining us. And good luck to the U.S. marathoners!

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