Although everyone wants to be fit, but there are very few people who are fit. I'll tell you one thing. Your physical health is so important because whatever work you do, you will do it with your brain. Eg :- Whenever I try to wake up in the morning. The alarm rings and I turn it off. I'm always thinking "what will I do when I wake up so early?"
It is only meant to say that if the body is lazy, then it will not allow your mind to do any work.