The 2014 Winter Olympics are underway in Sochi, Russia, rife with controversy around the proximity to the Chechen insurgency and recently anti-LGBTQ laws in Russia. But food for Olympic level athletes is itself a weird mix of science, superstition, and sacrifice.
For a competitive athlete, the diet can be complicated to deal with. In contrast to the average person, the rigors of training puts enormous demands on the athlete's body. Coupled with the competitive nature of sport that seeks to find any advantage not explicitly outlawed by the rules, and it creates an atmosphere ripe for exploitation.
Not commenting on the superstitious nature of dietary supplements (that's fodder for another day), but one of the challenges for professional athletes is being able to feed themselves while traveling. It's difficult enough to find prescribed dishes in places like airports, but meat is a particular problem when going to another country. The culprit is contamination by clenbuterol (street name "bute"), which is a hormone-like drug that can be used to boost aerobic capacity (albeit with side effects). Athletes aiming for Olympic qualification are routinely tested for clenbuterol use, and the FDA has banned the use of clenbuterol in animals destined for human consumption. However, it doesn't mean that other countries comply with this rule.
In fact, clenbuterol is most often used as an anti-asthmatic in horses, and can be used to produce leaner pork. But eating meat from such animals can result in athletes testing positive for clenbuterol, and contesting such a finding is most charitably described as "complicated". So, to avoid this, very often US athletes traveling in countries like China may opt to not eat the local fare, a sad irony given that one of the great pleasures of travel is sharing food with the locals.