During the 2010 Tour de France, the eventual winner Alberto Contador tested positive for a minute quantity of clenbuterol.

BBC: Ban on clenbuterol doping drug may be relaxed

What I do, then, is substitute quality for quantity and try to make at least 30 minutes in a 60-minute workout as hard as I can.

FORBES: In Praise Of (Mostly) Vegan Diets