When I’m working with a client who is training for a marathon the first thing I notice is how restrictive they are with their food. This is a problem because when you don’t eat enough while training, you tend to be hungry all the time, which can lead to poor food choices. Over time, poor food choices can lead to nutrient deficiencies. Deficiencies in important nutrients can not only compromise a runner’s training efforts, but can also cause problems long after the race is over.