By Mary Perry, Director of Clinical Trials:
Eating a giant bowl of spaghetti, three bagels and a couple of baked potatoes right before a big event is actually hurting your athletic performance. According to Dr. Sears, the idea that you should load up on carbohydrates the night before a race is a myth.
Mary Perry talks about what inspired her to train for three marathons and conveys training nutrition best practices, while sharing Dr. Sears’ expertise on the concept of carb loading for athletes.
My first job in Boston was located at about the 24-mile mark on the Boston Marathon route, not far from the Citgo sign at Fenway. In April, during the big race, my coworkers and I would take some time to go and stand on the sidelines looking for names on t-shirts, or something to identify individuals, so we could cheer them on as they went on to complete the last 2.2 miles.
Watching all of these runners with various levels of athleticism, spanning the ages of 20-70+, running either for charity or because they had qualifying times was absolutely inspiring. I saw that with the appropriate training, fueling, and determination that they didn’t have to be born runners to do this. This became my motivation to train and complete three marathons myself.
What I learned about performance nutrition during my training
It can be an individual journey involving a lot of trial and error to figure out what your body needs, when it needs it, and how to stay adequately hydrated, especially when Mother Nature is involved. I remember during my first marathon I was shocked to see that my weight was creeping up during my training instead of going down despite my activity level.
Looking back, it was a combination of not being as active on the days I trained due to soreness and fatigue, relying heavily on carbohydrates, and thinking I needed more calories than I actually did for all this activity. I began training for my second marathon shortly after starting my job at Zone Labs. Although at that point, I didn’t know what I know today, that even simple changes like decreasing carbohydrates and bumping up protein helped me to train smarter.
Despite having an injury and having to spend the last two months doing non-running activities, I was able to get through my second marathon without gaining weight and optimizing how I fueled. Although I’ll never see a qualifying time for the Boston Marathon, I was able to shave 27 minutes off my first marathon, which was my personal best.
With more and more individuals taking part in endurance events, whether they participate in marathons, triathlons, or the Ironman, there is a lot of advice out there from coaches, the internet, and apps on how people should train and fuel their bodies in order to successfully complete these races. Yet, an internet search may not be the best way to learn about good training nutrition.
Carbs are good, but must be balanced
According to Dr. Barry Sears, carbohydrates play an important role in athletic performance, but their over-consumption limits our body’s ability to use fat as an energy source. Fat should be considered “high-octane” fuel as you can generate far more energy (i.e. ATP production) from a gram of fat compared to a gram of carbohydrate. To maximize energy production, you want the enzymes in the mitochondria (the site in the cell that produces ATP) to have the maximum ability to burn both fat and carbohydrates. Being able to switch between carbohydrates and fats as an energy source is called “metabolic flexibility.” You can increase or decrease your metabolic flexibility with the composition of your diet.
Depending on the balance of carbohydrates and fat in the diet, the mitochondria will adapt their enzyme composition to maximize energy production based on which fuel it is able to access. If you are eating a high-carbohydrate diet, the mitochondria adapt by making more of the carbohydrate-metabolizing enzymes and less of the fat-metabolizing enzymes. The end result is that you are stuck using glucose, which is, for an athlete, the equivalent of putting low octane fuel into a Maserati. The results are much better using fat or high-octane fuel. So if you want the greatest metabolic flexibility your diet should consist of relatively equal intakes of both carbohydrates and fat.
Balancing your hormones play a role in sports nutrition
Dr. Sears further believes the balance of the hormones insulin and glucagon play a role in good sports nutrition. If you are eating a high-carbohydrate, low-protein diet, your blood sugar levels will constantly rise and fall. Carbohydrates stimulate insulin secretion which drives down blood sugar levels, whereas protein stimulates glucagon secretion which increases your blood sugar levels. You need a balance of the two so that blood sugar levels remain stable. This is why as an endurance athlete you have to work to balance your blood sugar levels at each and every meal as well as maintain metabolic flexibility. It may sound difficult, but it’s pretty easy.
How to get into the performance Zone
To maximize performance, a good diet leading up to race day is one that contains about equal levels of carbohydrate, protein, and fat on a caloric basis. The ideal diet is the Zone Diet™ because it is based upon your protein requirements, and from that knowledge you can automatically generate the amount of carbohydrate and fat you need for metabolic flexibility as well as maintain stable blood glucose levels.
Your diet should be comprised of colorful vegetables and fruits, adequate amounts of lean protein to maintain muscle mass, and enough good fats like those found in olive oil, nuts and seeds to displace omega-6 and saturated fats known to cause inflammation. Eating like this will give your body the metabolic flexibility it needs to convert whatever fuel you use on race day into the energy you need to compete at your highest level.
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