How to Eat for a Better Race
The first rule of training for any endurance sport is simple: you need lots of carbohydrates. Your muscles run on a fuel called glycogen, which is stored in the liver and in the muscles. It is converted from glucose (sugar), a common carbohydrate.
When you are exercising a lot, your body is burning glycogen, which must be replenished. When a person “hits the wall,” a common problem for marathon runners, that means the body is out, or nearly out, of glycogen and the energy is gone. Extreme fatigue sets in and it becomes almost impossible to move.
One reason you feel extreme fatigue when glycogen supplies run low is that your brain runs on glucose, which is converted to glycogen for the muscles. When glucose supplies get low, the brain tells the body it's tired. That is the brain's way of saving for itself what glucose is left.
Hitting the wall, or “bonking,” should not be a problem in your daily training in any workout that lasts up to an hour long, although hot weather training will speed the onset of glycogen depletion and shorten that window. It will behoove you to get used to a high-carb diet because of all the calories you will be expending as you train.
At a certain point in your training sessions, your body will begin to burn fat as a fuel, but it won't do so without carbohydrates, a kind of starter to the process. An axiom of endurance training is that “fat burns in a carbohydrate flame.”
Don't Keep It Simple
When it comes to carbohydrates, complex is much better than simple. Simple carbs, such as sucrose (table sugar), break down quickly in the body and can cause a spike in your blood sugar level. These are the famous “empty calories” you may have heard about. Consuming simple sugar may result in a burst of energy, but just as quickly there will be a “crash” in your blood sugar level, leaving you fatigued and craving more sugar. Further, because the sugar is broken down so quickly, it is immediately stored as glycogen, but cells have a limit to the amount that can be stored. The excess is converted to fat.
It takes the body a lot longer to break down complex carbohydrates, so you have a steady stream of energy rather than a series of spikes and crashes. Good sources of complex carbohydrates are whole grains such as oatmeal and brown rice, pasta, bagels, potatoes, and fresh or canned fruit. Simple sugars to avoid are in candy, cakes, table sugar, soft drinks, jellies, jams, and canned fruit in heavy syrup.
The difference in carbs accounts for the fact that many energy gels — what you would use during a race, especially a long one — are rich in carbohydrates and low in simple sugars. Simple sugar is good as a readily available carbohydrate source. When you are working out or racing, a small amount of simple sugar will not cause a crash because it is used quickly.
The recommended diet for athletes includes lots of fruits and vegetables, which might seem to be a contradiction because many fruits contain fructose, a simple sugar. These are natural sources of carbohydrates, and are low in simple sugar, and they contain fiber, which slows down the absorption of the sugar. Foods with added sugar are the ones to avoid.
Lest you think that your diet during your triathlon training will be nothing but bagels, lentils, and brown rice, there is one very important ingredient in your nutrition needs not mentioned so far: protein. As mentioned previously, building stronger muscles involves breaking them down through training, with the muscles growing stronger as they rebuild. A key component of that process is available protein. High-quality protein breaks down into amino acids, which support muscle repair and growth. Carbs are good for energy, but they don't help build your muscles.
Good sources of protein are lean meat, fish, poultry, eggs, milk, tofu, and yogurt. The best sources of protein for your purposes are those without a lot of fat. Yes, there is protein available in a double cheeseburger or pepperoni pizza, but those foods are high in the kind of fat that will slow you down and threaten your health.
Fat is an important component to your diet. Many vitamins are “fat soluble,” that is, they need fat to be absorbed by your body. Fat also provides long-lasting energy and helps your body produce hormones. Take in fat, but make sure it's the right kind: monounsatured or polyunsaturated, the kind you get from olive oil, canola oil, and omega-3 fatty acids in fish and leafy green vegetables. Stay away from saturated fat and trans fats.