Just love what you do, then you could experience what they call "flow" and, indeed, will need some self-discipline to remember to eat and sleep and exercise.) Self-control is mostly for struggling with boredom or fatigue.
I think it's a bit naive to think that the only reason for lack of focus on work is boredom or fatigue, and that it can be solved by loving your work.
I love my work, but wouldn't want to do it every waking moment. Also sometimes I hit a difficult bit of work and find it difficult to focus as I'm not progressing as quickly.
I love my work, but wouldn't want to do it every waking moment. Also sometimes I hit a difficult bit of work and find it difficult to focus as I'm not progressing as quickly.