Grandma’s Marathon is coming up soon – June 20th. That means Duluth restaurants, including us, are gearing up for serving lots of pasta. Everyone knows that pasta is the go to food when it comes to carbohydrate loading. Did you ever wonder what exactly carbohydrates are and how and where they are loaded? The answers lie in the marvelous system that Nature has developed for energy storage and consumption in animals.
Sugar (specifically glucose) is a primary energy storage and utilization molecule in animals. It is easily oxidized to obtain the energy necessary for life and easily stored in close proximity to the tissues which require it. It is soluble in blood and easily transported throughout the body. As with everything in bodies, glucose metabolism is highly regulated in its molecular pathways by feedback. In other words, if something is not present and needs to be present, it is created. Conversely, if it is present and is not needed, its creation is inhibited.
Glucose is a molecule that looks a lot like a beach chair in repose. All of the glucose used by animals comes from plants. It is created by them using the energy from photosynthesis. We have to eat plants to get it – and that is where the pasta bit comes in.
Most pasta is made from flour which is the ground up seeds of wheat plants. As you can see in the picture on the left, much of that seed is starch. The starch is placed in the seed as food for the baby plant contained in the embryo. Plants use six water molecules and six carbon dioxide molecules to make a molecule of glucose – and they use glucose in several ways. Most notable, it is used as a food and to create structure.
Starch and cellulose are both made from glucose – so the food provided by the seeds and the stalk that the seeds are held upon are very similar. The difference is the way that the glucose molecules are linked together. When animals eat plants the glucose that is in the starchy parts is digested and broken down into glucose and (except in ruminants) the cellulose is excreted.
Animal bodies move the glucose to the liver and to muscle tissue to be made into glycogen:
That glycogen is stored there until it is needed by the body. Notice that glucose/glycogen contain plenty of oxygen. That is what makes glucose so much easier to use during exercise than fat. Fat has no oxygen and requires it in order to be digested. Because oxygen is at premium in a race and because glucose can be utilized without any extra oxygen, it is much easier to use.
In a marathon, the runner’s muscles go first to the stored glycogen for energy. When that energy runs out, it is known as “hitting the wall.” The muscles react the way that they do not because they are out of fuel – there is still plenty of fat around – but because they are out of oxygen.
So that is why runners need pasta – so that their muscles can store up plenty of glycogen for easy use during the race.