I'm sure you're thinking why apply all the effort? I'll answer that THOROUGHLY here.
I'll be straightforward with you, this challenge isn't easy. Or else it wouldn't be called a CHALLENGE. In order to complete it, you're going to have to dig deep and acquire the motivation to keep going.
Time to get in the gym, pump some iron, and get those fat-burning muscles growing. No excuses.
If you want a high quality machine, feed it high quality fuel. The efforts of working out are greatly waisted without the right diet.
In order to MAXIMIZE your progress during the 21 days, and really take your body to the next level, include these high quality supplements into your regiment.