Anyone that says you can't eat healthy in Vegas is either not looking hard enough or is not wanting to do so. Part of Canyon Ranch Spa, the cafe is a surprising oasis of organic, healthy, well-priced, delicious food. The cafe is located inside where else...the Venetian (sorry, it's the best property in Vegas). Seats about 50-70 people and is pretty no frills when it comes to the decor which suits its mission. After all, it's about the food not the flair.
Their breakfast is great and very well-priced. Organic eggs are a plus and as far as I know they're the only place on the strip that offers them. Portion size is not massive, but again, they are going for the healthy lifestyle so didn't be upset if you leave and your gut isn't busting. Organic teas and juices are also available and delicious.
I think more places like this in Vegas would do quite well. Not everyone that goes to Vegas wants to gorge themselves on prime rib and lobster...just 99% of them.