All of this with the qualifier 'marathon runner' or 'endurance athlete', since explosive, short-duration, powerful sports require immediate energy reserves, whi

All of this with the qualifier 'marathon runner' or 'endurance athlete', since explosive, short-duration, powerful sports require immediate energy reserves, which they readily deplete when you do this type of exercise. Fat metabolism would be too slow for the quick, short types of activities. I also believe endurance or extreme endurance activities are more for your enjoyment than fitness. They take their toll on the body's joints, organs and regulatory systems. Moderation is good advice in lots of things.