Stay at high altitude for just one week ... you’re likely to have a more active lifestyle than you might in a city, which will also contribute to weight loss. Yes, you'll be a gassy, panting ...

Peru is home not only to the most voluminous river, the Amazon, and the world's highest lake, Titicaca, but also to the highest inhabited city on the planet.

Here is a classic scenario for developing a high altitude illness. You fly from New York City to a Denver at 5,000 feet (1,525 meters). That afternoon you rent a car and drive up to the trailhead at 8 ...