Schedule, or Inspiration?
Someone once asked the author William Faulkner whether he wrote on a daily schedule, or if he waited until he got inspired to sit and write. He replied, "Well of course, I only write when I get inspired. And fortunately for me, the inspiration strikes every morning at around 9am."
Of course, this outlook can also apply to working out, healthy eating, or really any activity that requires overcoming resistance--as nothing ignites the fire of inspiration like being consistent and scheduled.