Thank you for the thorough response.

From what I have read, health benefits of exercise itself level off after about 300 calories burnt per day

For what it's worth, I was curious about this because I bicycle a minimum of about two hours per week, usually more, depending on how busy I am. I don't do it for exercise, I do it for transportation, so the question was less "is this a good idea?" than "should I be taking this into account when making dietary decisions, and if so, how?"