Difference between interest and commitment

"There's a difference between interest and commitment. When you're interested in doing something, you do it only when it's convenient. When you're committed to something, you accept no excuses; only results" - Kenneth Blanchard

The above quote appeared in my news feed this morning, as a post from a fellow 12WBT'er.
It's easy to say that I'm interested in losing weight, but am I committed to it? Before seeing this quote I hadn't really considered the difference. I guess it is much the same as the difference between wanting to do something and actually doing it.  How do I go from being someone who is interested in having a healthy lifestyle to one that actually has a healthy lifestyle? By accepting no excuses, only results!

Hmm, I think Mish's 12WBT first preseason task is designed precisely to help with this. . .