Duluth is starting to gear up for Grandma's Marathon, a time when athletes from all over the world come to our city to compete. While many of us are not elite athletes, proper nutrition is an important component to making everyone's body perform its best.When it comes to sports nutrition, make sure to consume a well balanced diet of protein, carbohydrate and fat. This diet would include fruits, vegetables, lean proteins, whole grains and dairy (if able). During short to moderate exercise, our muscles'…