I saw this article linked on Twitter yesterday and read it on my commute home. I found the following points quite interesting:
Myth: If you train for a marathon or triathlon, surely your body fat will melt away.
Wishful thinking. If you are an endurance athlete who complains, “For all the exercise I do, I should be pencil-thin,” take a look at your 24-hour energy expenditure. Do you put most of your energy into exercising, but then tend to be quite sedentary the rest of the day as you recover from your tough workouts? Male endurance athletes who reported a seemingly low calorie intake did less spontaneous activity than their peers in the non-exercise parts of their day (4). You need to keep taking the stairs instead of the elevators, no matter how much you train. Again, you should eat according to your whole day's activity level, not according to how hard you trained that day.
I was thinking about this a lot as I was lying on the couch after my very challenging 60-min spin class last night. I know I've often used the excuse of, "Well, I just ran/biked X distance, I can just lie around the rest of the day." Or, "I have a tough workout coming up tomorrow, so I really should stay off my feet today."
And maybe those things are true from a pure training sense, but from a weight-loss perspective (for those of us who are trying to lose) it's really not a productive way of thinking.