A group of people who love yoga or work-out, or subscribe to a healthy lifestyle. What are they called? Is there a single-word for this particular group that describes them in a positive light?
I'd also appreciate any equivalent popular/recognized expressions that haven't yet entered any standard dictionary but have been buzzing around for a few years.
Since you're potentially interested in slang terms, you could consider granola.
Its meaning is something between "hippie" and "health-nut." It derives from the stereotype that these sort of people eat lots of granola.
http://www.urbandictionary.com/define.php?term=granola
An adjective used to describe people who are environmentally aware, open-minded, left-winged, socially aware and active, queer or queer-positive, anti-oppressive/discriminatory (racial, sexual, gender, class, age, etc.) with an organic and natural emphasis on living, who will usually refrain from consuming or using anything containing animals and animal by-products (for health and/or environmental reasons), as well as limit consumption of what he or she does consume, as granola people are usually concerned about wasting resources. Usually buy only fair-trade goods and refrain from buying from large corporations, as most exploit the environment as well as their workers, which goes against granola core values. The choice of not removing body hair (see amazon) and drug use are not characteristics that define granola people, and people, regardless of granola status, may or may not partake in said activities. This definition is sometimes confused with hippy.
My one caveat is that I'm not sure this term refers to living an athletic lifestyle, which seems to be part of what you're seeking.
The answer I fear may be a little on the nose. A person who enjoys doing yoga is a Yogi.
Yogi- A person who is proficient in yoga.
