Interview with Roberta Anding, MS, RD/LD, CDE: Part II
Let's talk a little bit about how the nutritional needs for marathon training and endurance training athletes are different.
The nutrient needs change based on the type of sport. So, as the intensity or the duration increases, carbohydrate becomes more important. Generally, the threshold is this: if your event goes on for greater then two minutes, you tend to use more aerobic pathways. You tend to use more carbohydrates. So, if you go out and run for an hour probably ninety percent of your fuel needs are being met by carbohydrate. So, a key thing for marathoners is to pay attention to how much carbohydrate you are taking in. And, certainly when you say that, not all carbohydrates are created equal.
So, it's not all candies, cakes, and pies; it tends to be more of a balance between whole grains, fruits, vegetables, beans, yogurt--the traditional kind of carbohydrate foods with always that ever present eye on tolerance. For example, fruit is a great carbohydrate choice; an average piece of fruit has as much carbohydrate as a slice of bread. The problem is, I might not be able to tolerate nine pieces of fruit in a day. I could end up with gastric distress; I might end up with a little bit of diarrhea; I can't handle all that fiber. So, when I say there is an important aspect of keeping your eye on adequate amounts of carbohydrates, you also have to kind of keep in mind what the athlete's system will tolerate. If I tolerate cereal well maybe I will go from something like Cheerios to Grape Nuts; to get more carbohydrate in less space. I had a long distance runner at Rice University, who was 6'2", 150 pounds, and his weekly mileage was huge. He was eating probably fifty percent to fifty-five percent of his diet as carbohydrate. He just got too full with his traditional carbohydrate foods. and so we had to use more liquids and gels and other things because he just couldn't take the volume anymore.
How much carbohydrate does an endurance athlete need?
Endurance athletes, as opposed to my anaerobic athletes, really need more carbohydrate. Most of the science will say somewhere in the range six to ten grams of carbohydrate per kilogram of body weight. And, so if you are seventy-five kilos and you need ten grams of carbohydrate; that's seven hundred and fifty grams from lots of bread and pasta and rice and fruit.
How do you look at the high glycemic index verses low glycemic index of a carbohydrate as a factor?
I use it; I use the low glycemic index carbohydrates as my endurance carbohydrates, the ones that are going to give me sustained energy. I use the high glycemic index carbohydrates for recovery; I like those immediately post-run. And, what the science will say is that the faster I can get that carbohydrate into my system (ideally within the first fifteen minutes to twenty minutes), the better. I can increase my glycogen stores maybe twenty-five percent to thirty percent. That is a real performance benefit. I like the high glycemic index carbohydrates for recovery. I do have some athletes that the closer it gets to the run, they actually like to start adding some higher glycemic index carbohydrates. I've also had some endurance athletes who do that right before they run, but they become hypoglycemic and their blood sugar goes up and down too quickly; and they don't do well. So again, you take the science of sports nutrition and you tweak it to meet individual preferences, religious beliefs, tolerance, and all the other factors that fortunately make us not all identical twins. So, what would work for you, may not work for your training partner.
One of the guys that I work with here ended up drinking a smoothie an hour and a half before a training run. He was about twenty-five minutes into his run and he said "I was pale, I was clammy, I was cold, I knew I was hypoglycemic".
He said "I just felt awful", and so again I am not a real big fan of using really high glycemic index carbohydrates before runs, unless I know somebody well. Things like oatmeal and yogurt have a lower glycemic index and work well for most people. I even have a couple of my Rice University athletes who will eat lentils before they run--really low glycemic index, they've got enough GI tolerance that they don't gas, and they don't get diarrhea from it.
Now, I could recommend that to somebody else and they'd say ,"Are you crazy? I am not eating lentils and yogurt." But, they may eat something like oats, low-sugared yogurt, some egg whites, or maybe even some protein powder thrown into that oatmeal before they go run.
What about electrolytes in this whole picture, such as potassium and sodium?
Yes. That's actually a pretty tough call, and the reason it's a tough call is, sodium in the long run probably isn't really great for any of us. Americans tend to have a chronic sodium overload. The problem is for athletes; we are not really looking at the chronic effects of sodium, but the acute effects of sodium depletion. And, certainly dealing with professional football players in Houston Texas in July, I've got some real problems with sodium wasters.
They may become hyponatremic but, they also cramp like crazy. Hyponatremia to me means something a little bit different. And, what it means to me is that generally someone over-drank water. Doing that you can become sodium depleted and not really become fluid reloaded. And, drinking plain water probably isn't to your advantage.
You know this, you sweat salt, you drink water, you sweat salt, you drink water; and sooner or latter you can end up with the delusional hyponatremia. Not because you are really overdrinking but, because you drank the wrong product. One of the guys I work with is the Assistant Medical Director for the Houston Marathon. He found that the people who are most likely to become hyponatremic who were distant runners were women who were slow runners.
Now, again with my football players -- certainly Rice University, the Texans, and the high school kids here in Houston -- the dilemma becomes that salt is truly that four letter word where people say to me, "Why are you telling my son, or daughter to drink a sports drink?; Why are you telling them to salt their food?" And, the reason is I am trying to counterbalance the acute effects of sodium depletion; not the chronic effect of sodium overload, which probably affects more Americans.
So, I am trying to counterbalance that. Most of the time, the cramping that athletes experience has nothing to do with potassium; it's almost always sodium. It's dehydration and sodium depletion that's going to cause the cramping.
Interesting, because I thought that sodium was mainly associated with brain- related issues and potassium was associated with muscle related issues.
Well, potassium is an intracellular cation. And sodium's job is to get muscles and nerves to talk to one another. There are two major reasons why an athlete may cramp: (1) you are dehydrated and sodium depleted, or (2) you significantly increased your training volume. So, for example look at what happened in the Super Bowl this year. You had athletes cramping on the sidelines because they weren't used to playing in a dome. It was hotter in a dome than they were used to and their defense was on the field longer than they have been in a while.
Their training load increased; their physical work load increased. And, so the muscles, the muscle fibers aren't firing in a synchronized way, it's actually called asynchronous firing where the muscle fibers don't fire correctly because you've increased your training volume. So, if you and I were to go run together, and you are used to going out and doing twenty mile runs, and I attempted to keep up with you, I am going to cramp. Probably not because of dehydration, because I know how to hydrate, and I know how to salt my food. I am just not used to that training volume. The athletes who I see that cramp, that are potassium-related, are in general bodybuilders; and the reason is that the type of competitive diet that I see bodybuilders use is more of an Atkin's kind of a diet. The Atkin's diet is very low carbohydrate, and they are trying to cut maximum amounts of body fat.
So, they go on six small meals a day, egg whites, chicken breast, maybe a few small amounts of low glycemic index carbohydrates thrown in. And, what ends up happening is, because they don't have any carbohydrate, the potassium doesn't stay locked inside the muscle; the potassium ends up in the blood supply, they urinate it out, they end up potassium depleted, and they cramp. So it is not that potassium can't cause cramping. It's just rare.
So a lot of times the cramping results from the scaling of the level of effort?
Absolutely, I don't cramp when I do really aerobic exercise, but I cramp when I lift weights because I am trying to lift heavier amounts of weight every time I go into the weight room. At some point in time the load is more then I can handle, so I cramp. And, it's not necessarily the muscle that I am using; it could be another muscle. It's because I am trying to recruit enough muscle fibers to get those muscles to contract, and because the training volume is significantly greater than it was the last time. I am not conditioned to that level of activity.
Do you have any other dietary tips that you would recommend to amateur or even higher-level athletes who read this article?
Yes, I think the under-rated nutrient that often times is left out of the discussion is fat; and the key is, just like we talked about with carbohydrates -- not all carbohydrates are created equal, nor are all fats.
Many athletes are terrified of adding fat because, they think when you eat fat, you get fat; but it doesn't quite work that way. If I have someone who really needs to gain weight and they are underweight, they are too thin for their position, they are having performance-related issues. I will add some high quality fats to their diet in order to help them to meet their calorie needs. So, when we talk about protein building and all the beneficial things about protein, we forget that calories bodyguard protein. You need enough calories so that the proteins don't become your source of energy.
Obviously your body must meet its energy needs first, its protein needs second. So, I need to have enough calories and, often times high quality fat. I am not talking about bacon and sausage and animal fat products. I am talking about things like Trail Mix, nuts, or dried fruit; it's about six hundred calories a cup. So, if you are trying to loose weight, Trail Mix is probably not your friend. If you are trying to gain weight, or you always have trouble during your season with losing too much weight, I like Trail Mix. It doesn't spoil, it doesn't squash; you can pack up six bags on Sunday night and keep it in your locker and it's still going to be good to go all week long. You can't do that with a turkey sandwich; milk, and some other foods, but Trail Mix becomes a nice source of heart-healthy fats.
And Omega 3 and Omega 6 acids have anti-inflammatory properties as well?
Yes. I often recommend Omega 3 fatty acid supplement.
Something like flax-oil?
I would probably say fish-oil.
And, why is that?
Flax is an eighteen carbon fatty acid. It has eighteen carbons in its chain. Fish-oil has either twenty or twenty-two. There is one enzyme system responsible for getting that flax to the more beneficial forms which are the twenty and twenty-two carbon. Most of the anti-inflammatory properties come with the longer chain fatty acids. Very cool physiology--your body can take that flax under ideal circumstances and convert it into the more beneficial forms, the twenty and twenty-two carbon. If I eat a traditional American diet with corn oil and sunflower oil; they are filled with Omega 6 fatty acids. But, Omega 3's and Omega 6's are like fighting siblings.
They fight for the same enzyme system, and if I over-flood this system with Omega 6's, they win. And, that's the way the typical American diet is. So even if you eat enough Omega 3's you can still not get their benefits if you have too many Omega 6's.
But, my preference is actually fish-oil. It is not that flax isn't a great thing to add to oatmeal. It's a good source of fiber, good source of lignans, and a good source of antioxidants. It's a great food, but it's not the best anti-inflammatory. So, I recommend fish-oil instead.
Interesting. The argument that I've heard for flax is that it has more Omega 3 than Omega 6, in an appropriate balance; but what you're saying is that its Omega-3's are not in the optimum form?
Correct, what you are trying to do is modify the synthesis of prostaglandin, and prostaglandins are hormones like compounds that exert their effects in multiple systems throughout the body. I want to hedge my bet and say, yes flax is a great source of Omega 3. However, I am trying to get the most bang for the buck out of those Omega 3's that I can, and the further I get them along the chain (Editor: i.e., the higher carbon forms), probably the better they are for me.
So in a perfect world, I probably would tell you put a little flax (ground flax) on your oatmeal in the morning and then take a gram up to two grams of fish-oil per day.
Just a couple of grams?
Just a couple of grams. So that way, you get the best of both worlds.
Right, excellent. Thank you for speaking with us today.
Roberta Anding, MS, RD/LD, CDE, is an instructor in the adolescent and sports medicine, department of pediatrics, at Baylor College of Medicine (BCM) in Houston. Her research interests include risk factors for the female athlete triad, prevalence of eating disorders in health care professionals, and determinants of dietary supplement use in college athletes. In addition to being on faculty at BCM, Anding is an instructor in the department of kinesiology at Rice University. She also is currently the American Dietetic Association's Houston spokesperson and a nutrition consultant for the Houston Texans Football team.