Honestly, you don't want to lose more than... I think like 2 poundsa a week. MOre than that and it's TOO much, too fast, and just not healthy.
But! I can say this much
You could try what I'm tryin'. I can't speak for the effectiveness for weight, but I do yoga and I CAN speak for how it will help with flexibility. Holy hell will it.
Also, look into a bike. They're better than walking (faster! XD And more effective for the weight thing). Seriously. If you bike for a bit every day, build that up more and more until you can go for awhile, and do yoga every couple days [twice a week, for example] it should, in theory, help you lose weight.
At least that's what I'mma be doing once I get a bike again. Lol